Interfacesof HEIDENHAIN Encoders

12/2021

Interfaces

As the defined link between encoders anddownstream electronics, interfaces ensure
the reliable exchange of information.
HEIDENHAIN offers encoders withinterfaces for many common downstream
electronics. The specific interface that canbe used depends on the encoder’s methodof measurement and other factors.
Methods of measurement
In the incremental measuring method,
the position information is obtained bycounting the individual increments(measuring steps) starting from a selected
point of origin. An absolute reference pointis needed for determining the position, so
a reference-mark signal is output as well.
Incremental encoders generally output
incremental signals. Some incremental
encoders with integrated signal converters
have a counting function: once the referencemark is traversed, an absolute position
value is generated and transmitted via a
serial interface.
In the absolute measuring method, theabsolute position information is acquired
directly from the grating of the measuring
standard. The position value is available

Contents

Serial data transmission

Note:
Specialized encoders can have otherinterface characteristics (e.g., with regard
to shielding).

Serial interfaces

EnDat

Bidirectional interface

With incremental signals

4

Without incremental signals

from the encoder immediately uponswitch-on and can be requested at any
time by the downstream electronics.
Encoders that use the absolute measuring method output position values.
Some interfaces provide incremental
signals as well.

Signal converters
Signal converters from HEIDENHAIN let
you flexibly adapt your encoder signal
interfaces to the requirements of yourapplication. Depending on the application,
additional signals (such temperature-sensor
signals) may be processed and transmitted
to the downstream electronics.

Since absolute encoders do not requirea reference run, they are ideal for use
in concatenated manufacturing systems,
transfer lines, and multi-axis machines.
They are also highly immune to EMC
disturbances.

11

Siemens

Proprietary interface

Without incremental signals

Fanuc

Proprietary interface

Without incremental signals

Mitsubishi

Proprietary interface

Without incremental signals

Yaskawa

Proprietary interface

Without incremental signals

Panasonic

Proprietary interface

Without incremental signals

PROFIBUS DP

Fieldbus

Without incremental signals

12

PROFINET IO

Ethernet-based fieldbus

Without incremental signals

14

SSI

Synchronous serial interface

With incremental signals

16

1 VPP

Voltage signals, highly interpolatable

18

11 µAPPCurrent signals, interpolatable

21

TTL

RS-422, typically 5 V

22

HTL

Typically 10 V to 30 V

25

HTLs

Typically 10 V to 30 V, without inverted signals

Incremental signals
Sinusoidal signals

Square-wave signals

Other signals
Commutation signals

Limit/homing

Block commutation

27

Sinusoidal commutation

28

Limit switches

29

Position detection

30

Further information

Further information:• www.heidenhain.com/products/
signal-converters• Brochure: Cables and Connectors

2This brochure supersedes all previous
editions, which thereby become invalid.
The basis for ordering from
HEIDENHAIN is always the brochure
edition valid when the order is placed.
Standards (ISO, EN, etc.) apply only
where explicitly stated in the brochure.

Signal converters

32

Testing and inspection devices, and diagnostics

34

Measuring principles

38

General electrical information

39

Cable lengths

41				 Proven and continuously developed
interface technology

EnDat 3 carries forward the features andbenefits of EnDat into the future of digitalmanufacturing. To achieve this feat, EnDat 3
relies on a new architecture that builds
upon proven technology, ensuring optimal
continuity and compatibility with predecessor
interfaces.
EnDat 3 characteristics:• Hybrid cable transmission• Bus topologies• Sensors: versatile data contents andsensor box• Functional safety: black-channel
communication• Higher data bandwidth• Definable send lists• System installation: introduction ofaccess levels

Communication

Interface
ProtocolRequest-response procedures in half-duplex mode

Physical layer

RS-485: 4-wire or 2-wire

Data rate

12.5 Mbit/s (25 Mbit/s)

Cable length

For 12.5 Mbit/s: max. 100 m / for 25 Mbit/s: max. 40 m

HPF send time(position availability
in the master)

Typically 10 µs (the parameter XEL.timeHPFout indicates theduration between position value generation (stored via latch)and transmission of the complete HPF, without cable effects)

Cycle time

Typically > 25 µs

Bus operation

Daisy chain

Functional safety

Designed for up to SIL 3, black-channel communication

EnDat 3 requires two wires for communication. Two other wires are generally usedwith EnDat 3 for supplying power to theencoder. Thanks to the lack of a DC component, communication can be modulated
onto the supply wires, thereby reducing
the number of wires to a total of two forcertain applications (e.g., hybrid motor­cables). The EnDat 3 interface specifiation
follows an OSI-based layer model.
The encoder-end of the interface is called theslave, and the downstream electronics themaster. Communication occurs in half-duplex
mode. A communication cycle consists ofa request from the master followed by a
response from the slave. Communication
between the master and slave is subdivided
into foreground communication andbackground communication.

Functions

Ordering designations
The ordering designation defines key
communication characteristics

For condition monitoring and predictive maintenance

System information

Automated configuration and storage of operating status data

Access control

User authentication (e.g., for datum shift, OEM memory)

Supported
communication types

E30-R2

E30-R4

E30-RB

EnDat 3:
communication modulated
onto power supply wires



–

–

EnDat 3:–
communication + separate
power supply wires (4 wires)

EnDat 3: bus operation

–

–



Sensor box integration

–





Further information:www.endat.deD
Encoder
Encoder+

Cc

Block diagram: 2-wire4

UE

Subsequent
unit
Downstream

electronics

D

Housing
Housing

Angle

31Standardized position formats
Encoder profiles
Error handlingAccess levels....

0

16 Bit MT

32 Bit ST

BGD

Transport Layer

Foreground
Background (embedded in the Foreground)
Send lists (predefined communication)
Bus operation....

Wort 00
Word

ForegroundandBackground

Wort 11
Word
Wort 22
Word

Data Link Layer
and Network
Layer

BUS REQ

Request-response procedure
Defined data frames....

HPF LPH LPF LPF

RS-485, 2-wire / 4-wire
12.5 Mbit/s / 25 Mbit/s
Bus operation....

Physical Layer

EnDat 3 communication layer model

Diagnostics

Connection
Connection
designation
designation

47

Application
Layer

L

-

Ubat
GND

L

RS-485

P_SD+

C TR

R

P_SD-

Rs

R

Cm

Housing
Housing

Foreground communication
Foreground communication is for data thatmust be available in the communication
cycle (e.g., controller cycle).
Requests and responses are organized intoframes with a defined length. Each request
and response begins with a preamble (PRE)and ends with a postamble (POST). The REQ
request frame controls communication
with the encoder or triggers certain actions
within it (e.g., clearing of error messages),
thereby also determining the contents of
the response. Irrespective of the REQ frame
contents, the response frame is chrono­
logically divided into high-priority data andlow-priority data.
A response contains the following elements:• One HPF (High Priority Frame)
The HPF typically contains the encoder
position. Depending on the encoder,
other information can be specified fortransmission in the HPF as well.
• One LPH (Low Priority Header)
The LPH carries status information about
the subsequent data contents. It also
contains information about the send list
and the number of transmitted LPFs.
The send list specifies the chronologicalsequence of LPFs within the individual
communication cycles.
• Up to 15 optional LPFs (Low Priority
Frames)LPFs can carry additional data, such as
diagnostic values, sensor information, or
redundant information for functionalsafety.

The LPFs used in EnDat 3 build upon theconcept of additional data found in EnDat 2.2.
The switch between various LPFs isperformed in accordance with a send list
configured in the encoder’s memory. The
downstream electronics do not need tointervene in the controller cycle. The send
list can be configured either in the encoder’svolatile memory after each restart orpermanently in its non-volatile memory.
During operation, the send list specifies
which LPFs are to be included in the
response from cycle to cycle. Up to eight
different send lists can be stored in thememory. The type of request determines
which send list is active, thereby allowing
the downstream electronics to respondwith speed and flexibility to various
operating statuses.
A sample communication cycle is shown
below. A complete communication cycle
always contains the white fields, as well as
up to 15 optional LPFs (in gray). A CRC(Cyclic Redundancy Check) safeguards the
REQ, HPF, and LPH protocol contents andeach LPF.

Background communication
Some tasks, such as reading from andwriting to the encoder memory, have low
timing demands. For these kinds of tasks,
EnDat 3 defines a background channel.
Background communication is embeddedin the foreground communication and uses
its frames as transport carriers (REQ, LPH,
LPF). The background channel thus makes
it possible to read from and write to theencoder memory in the controller cycle.
However, the background channel cannot
handle real-time demands.
Bus operation
Along with point-to-point mode, EnDat 3 alsooffers bus operation for special applications.
In bus operation, a Bus Request Frame isadded in front of the Request Frame, thus
allowing multiple participants to send
responses in a single communication cycle.

RequestPRE

REQ
4 ByteResponse
POST

PRE

HPF

LPH

LPF

8 Byte4 Byte8 BytePOST

Communication cycle

Further information:• EnDat 3 Interface Specification• www.endat.de5Connection technology

Functional safety
EnDat supports the use of encoders insafety-related applications in accordance withthe following standards: DIN EN ISO 13849-1(successor to EN 954-1), as well as EN 61508
and EN 61800-5-2. In these standards,
safety-related systems are assessed basedon the failure probabilities of integrated
components and subsystems, along withother criteria. This modular approach helps
manufacturers implement their complete
systems by allowing them to build uponpreviously qualified subsystems.
The functional safety provided with
EnDat 3 encoders for applications up to
SIL 3 is based on the following factors:• Position value– Two independent position values:
Pos1 (high resolution) and Pos2
(low resolution, if applicable)– Comparison of Pos1 and Pos2 by
the safe control unit
• Forced dynamic sampling– Cyclic testing of the monitoring
function in the encoder• Error messages– Monitoring of error bits F1 and F2• Due to the black channel, a safe EnDat
master is not required and is thus notpart of the safety chain• Separation of communication to the
motion controller and safe control unit
(e.g., separate error messages)

Diagnostics
EnDat enables extensive encoder monitoringand diagnostics without an additional line.
Its diagnostics generate valuation numbers,
error messages, and warnings, and are a
key ingredient in attaining high availability inthe complete system.
The important factors:• Machine utilization planning• Support for the on-site service technician• Easy evaluation of the encoder’s function
reserve• Simplified troubleshooting for repairs• Creation of informative quality statistics
For an analysis of encoder functionality,
valuation numbers can be read cyclicallyfrom the encoder. Valuation numbers provide
information about the current status of
the encoder and its function reserve.
Their identical scaling for all HEIDENHAIN
encoders enables consistent analysis. The
function reserves, combined with othersensor data, serve as the basis for condition
monitoring and predictive maintenance inthe higher-level downstream electronics.

In summary:
Convenient implementation is possible
thanks to the black-channel approachcombined with standardized position data
formats and the option of moving forced
dynamic sampling to the encoder.

System information
EnDat provides information about theencoder and the system in the form of anelectronic ID label:• Encoder parameters, which are all of theparameters needed for initial encoder
configuration, are stored in the encoder.
• System parameters can be stored in theencoder’s memory by the OEM or plantbuilder, and accessible areas can be
password-protected.
• System or process status data, referred
to as operating status data, can be stored
in the encoder during normal operation;
the encoder can even collect operating
status data on its own.
Access control
Memory areas can be protected by various
levels of user authentication. The available
access levels are OEM1, OEM2, and User.
Authentication is performed with a 32-bit
password. As shipped, the encoder’s OEM1,
OEM2, and User areas are vacant andprotectable by separate passwords.
Singleturn and multiturn information canalso be separately configured and protected.
Typical implementation:• OEM1 (motor manufacturer): singleturnis set, and OEM1 memory is written to.
A password is defined; the OEM1 area
is protected.
• OEM2 (machine manufacturer): multiturnis set, and OEM2 memory is written to.
A separate password is defined;
the OEM2 area is protected.
• User (customer): the User memory
can be written to. A separate password
is defined; the User area is protected.

Encoders with the purely serial EnDatinterface predominantly use 8-pin M12 and9-pin M23 connecting elements. Thiswidespread connector technology offers
the following benefits:• Cost-effective connection technology• Smaller connector dimensions andthinner connecting cables

CablesHigh transmission frequencies over longcable lengths place rigorous technologicaldemands on the cable. Specifically designed
for this purpose, HEIDENHAIN cables are
qualified to handle this type of application.
We therefore recommend using
HEIDENHAIN cables.

Through its lower number of wires, EnDat 3
offers further options for miniaturizing theconnection technology and adapting it to
the application requirements.

4-wire technology
In the 4-wire variant, the master powers
the encoder with one wire pair and uses a
second wire pair to communicate with theencoder.

Connection
Connection
designation
designation
Encoder
Encoder

UE

Up
0V

SD+
SD-

Housing
Housing

Subsequent unit
Downstream
electronics

GND
RS-485R

Cm

R

2-wire technology (HMC 2)
Unlike the 4-wire option, the 2-wire variant
requires additional hardware. In thisconfiguration, the downstream electronics
power and communicate with the encoder
on the same wire pair. For this purpose,the encoder power supply and data stream
are separated by frequency dividing
networks (one on the master and one on
the slave).
4-wire bus in daisy-chain modeThis variant allows encoders to be operated
on a daisy-chain bus. Unlike the 4-wire variant,the 4-wire daisy-chain bus variant requires
an additional transceiver branch inside theencoder. This additional transceiver branchestablishes the data connection to the next
encoder on the bus. The 4-wire daisy-chain
bus variant also supports the 4-wire variant.
Sensor box
With the 4-wire variant, a sensor box canbe inserted.
Power supply
The supply voltage and power consumption
are stated in each encoder’s specifications.
For encoders with the EnDat 3 interface,a supply voltage of 12 V (±5%) is
recommended.

Housing
Housing

4-wire block diagram

Further information:• EnDat 3 Application Conditions for
Functional Safety• www.endat.de

Further information:• EnDat 3 Hardware Specification• Brochure: Cables and Connectors• Product Information doc.: HMC 6• Product Information doc.: HMC 2• www.endat.de
Sample display of the function reserve
HMC 2 single-cable solution:
standard components for a reliable connection

6

7

The EnDat interface is a digital bidirectional
interface for encoders. It can output position
values, read and update information stored
in the encoder, and store new information in
the encoder. Thanks to the interface’s serialtransmission method, only four signallines are required. The data are transmitted
synchronously to the clock signal provided
by the downstream electronics. The typeof transmission (position values, parameters,
diagnostics, etc.) is selected via mode
commands sent to the encoder by thedownstream electronics. Some functions
are available only in conjunction with
EnDat 2.2 mode commands.
History and compatibility
The EnDat 2.1 interface, which has been
available since the mid-1990s, has since
been upgraded to EnDat 2.2 (recommended
for new applications). In terms of its
communication, command sets, and time
conditions, EnDat 2.2 is compatible with
EnDat 2.1 but also offers significant
advantages. For example, EnDat 2.2 permits
the transfer of additional data (sensor
values, diagnostic data, etc.), along withthe position value, without initiating aseparate request. This allows the interface
to support additional types of encoders(e.g., encoders with buffer battery backup,
incremental encoders). The interface
protocol has also been expanded, andtiming factors (clock frequency, calculation
time, recovery time) have been optimized.
Supported encoder types
The following encoder types are currently
supported with the EnDat 2.2 interface(readable from the memory area of theencoder):• Incremental linear encoders• Absolute linear encoders• Incremental, singleturn rotational
encoders• Absolute, singleturn rotational encoders• Multiturn rotary encoders• Multiturn rotary encoders with buffer
battery backup
For the various encoder types, someparameters must be interpreted differently(see the EnDat specifications), or EnDat
additional data must be processed (e.g.,incremental encoders or encoders withbuffer battery backup).

Interface

EnDat serial bidirectional

Data transmitted

Position values, parameters, and additional data

Data input

Differential line receiver in compliance with EIA standard RS-485
for the CLOCK, CLOCK, DATA, and DATA signals

Data output

Differential line driver in compliance with EIA standard RS-485
for the DATA and DATA signals

Position values

Ascending during movement in the direction of the arrow(see mating dimensions of the encoders)

Incremental signals

Depends on the encoder» 1 VPP, TTL, HTL (see each type under Incremental signals)

Ordering designations
The ordering designations define the key
specifications and provide the following
information:• Typical power supply range• Command set• Availability of incremental signals• Maximum clock frequency
The second position in the ordering designation identifies the interface generation.
For current-generation encoders, the ordering
designation can be read from the encoder
memory.
Incremental signals
Some encoders also provide incremental
signals. These signals are primarily used forincreasing the resolution of the position
value or for providing data to a second
downstream device. Current generationsof encoders have a high internal resolution
and therefore no longer need to provide
incremental signals. The ordering designation
indicates whether an encoder outputs
incremental signals:• EnDat01 With 1 VPP incremental signals• EnDatH With HTL incremental signals• EnDatT With TTL incremental signals• EnDat21 Without incremental signals• EnDat02 With 1 VPP incremental signals• EnDat22 Without incremental signals
With regard to EnDat01/02:
The signal period is stored in the encoder
memoryWith regard to EnDatH/EnDatT:The interpolation factor with which theinternal incremental signals are output isindicated by a single letter added to theordering designation:• a 2-fold interpolation• b Without interpolation• c	0.5-fold interpolation (incremental
signals/2)

8Supply voltage
The typical supply voltage of the encoders
depends on the interface:
EnDat01
EnDat215 V ±0.25 V

EnDat02
EnDat22

3.6 V to 5.25 V or 14 V

EnDatH

10 V to 30 V

EnDatT

4.75 V to 30 V

Exceptions are documented in thespecifications.
Command set
The command set describes the available
mode commands, which define theinformation exchange between theencoder and the downstream electronics.
The EnDat 2.2 command set includes all
EnDat 2.1 mode commands. In addition,
EnDat 2.2 permits further mode commands
for the selection of additional data andenables memory accesses even in a closed
control loop. When a mode command fromthe EnDat 2.2 command set is sent to an
encoder that supports only the EnDat 2.1
command set, an error message is triggered.
The supported command set is stored in
the encoder’s memory area:• EnDat01/21/H/T	Command set 2.1
or 2.2• EnDat02/22		
Command set 2.2

Clock frequency
The clock frequency is variable between
100 kHz and 2 MHz depending on thecable length (maximum: 150 m). Withpropagation-time compensation in thedownstream electronics, clock frequenciesof up to 16 MHz or cable lengths of up to
100 m are possible. In the case of EnDat
encoders with the ordering designation
EnDatx2, the maximum clock frequency isstored in the encoder memory. For all otherencoders, the maximum clock frequency is
2 MHz. Propagation-time compensation isprovided only for the ordering designations
EnDat21 and EnDat22; for EnDat02, see
the note below.
EnDat01
EnDatT
EnDatH≤ 2 MHz (see “without
propagation-timecompensation” in the
diagram)

EnDat21≤ 2 MHz

EnDat02≤ 2 MHz or≤ 8 MHz or 16 MHz(see note)

EnDat22≤ 8 MHz or 16 MHz

In conjunction with long cable lengths,transmission frequencies of up to 16 MHz
place high technological demands on thecable. For reasons concerning the transmission technology, the adapter cable­connected directly to the encoder must not
be longer than 20 m. Longer cable lengths
can be realized with an adapter cable nolonger than 6 m and an extension cable.
As a rule, the entire transmission path must
be designed for the given clock frequency.
Note on EnDat02
EnDat02 encoders may have a pluggable
cable assembly. In choosing the version of
the adapter cable, the customer decides
whether the encoder will be operated
with or without incremental signals. This
also influences the maximum possible
clock frequency. For adapter cables withincremental signals, the clock frequency islimited to 2 MHz; see also EnDat01. For
adapter cables without incremental signals,
the clock frequency can be up to 16 MHz.
The exact values are stored in the encoder
memory.

Cable length in m 				 The bidirectional interface

Clock frequency in kHzEnDat 2.1; EnDat 2.2 without propagation-time compensation
EnDat 2.2 with propagation-time compensation (by the EnDat master)
Under certain conditions, cable lengths of up to 300 m are possible after consultation with
HEIDENHAIN

Position values
The position value can be transmitted withor without additional data. At the earliest,
the position value is transmitted to thedownstream electronics after the calculation
time tcal has elapsed, or after 14.5 clock
pulses. The calculation time is determined
for the encoder’s highest permitted clock
frequency, but for no more than 8 MHz.
For the position value, only the required
number of bits is transferred. The numberof bits thus depends on the given encoder
and can be read from the encoder for
automatic parameterization.
Typical operating modes
Operating mode EnDat 2.1: This modeis for encoders that provide additional
incremental signals. For generation of
the position value, the absolute position
is read once simultaneously with theincremental position, and both are usedin the calculation of the position value.
The subsequent generation of the position
value in the control loop is based on theincremental signals. Only EnDat 2.1 mode
commands are used.
Operating mode EnDat 2.2: This mode isfor purely serial encoders. For position
value generation, the position value is readfrom the encoder during each control cycle.
EnDat 2.2 mode commands are typicallyused to read the position value. EnDat 2.1
mode commands are typically used to read
and write parameters after switch-on.
In the closed control loop, the EnDat 2.2
interface allows additional data to berequested along with the position, and it
permits the execution of functions (e.g.,
read/write parameters, reset error
messages).

Additional data
Depending on the type of transmission(selection via MRS code), one or two itemsof additional data can be appended to theposition value. The types of additional data
supported by the respective encoder are
saved in the encoder’s parameters.
Additional data encompasses the following:
Status information, addresses, and data
• WRN: warnings• RM: reference mark• Busy: parameter request
Additional data 1• Diagnostics• Position value 2• Memory parameters• MRS-code acknowledgment• Test values• Temperature• Additional sensors
Additional data 2• Commutation• Acceleration• Limit position signals• Asynchronous position value• Operating status error sources• Timestamp

9Company-specific serial interfaces

Parameters are stored in various memoryareas, e.g.:• Encoder-specific information• Information from the OEM (e.g.,
electronic ID label of the motor)• Operating parameters (datum shift,
instruction, etc.)• Operating status (alarms or warnings)
Monitoring and diagnostic functionsof the EnDat interface enable a detailed
inspection of the encoder. These include
the following:• Error messages• Warnings• Online diagnostics based on valuation
numbers for easily determining thefunction reserves of an encoder• Parameters for mounting the encoder

Absolute encoder

Downstream electronics
Incremental
signals *)Absolute
position value

Operatingparameters

Operatingstatus» 1 VPP A*)
EnDat interface

Memory areas
The encoder provides multiple memoryareas for parameters. These memory areas
can be read by the downstream electronics,
and some areas can be written to by theencoder manufacturer, the OEM, or theend user. The parameter data are stored inpermanent memory. This memory allows
only a limited number of write accesses
and is not designed for the cyclic storageof data. Certain storage areas can be writeprotected (resettable only by the encoder
manufacturer).

Parameters of the encoder
Parameters manufacturer forof the OEM
EnDat 2.1
EnDat 2.2

System information
EnDat provides information about theencoder and the system in the form of anelectronic ID label:• Encoder parameters, which are all of theparameters needed for initial encoder
configuration, are stored in the encoder.
• System parameters can be stored in theencoder’s memory by the OEM or plantbuilder.
• System or process status data, referred
to as operating status data, can be
stored in the encoder during closed loop
operation.

» 1 VPP B*)

Interface

Designation inbrochure

Ordering
designation

Code letter

Siemens

Siemens
DRIVE CLiQ

DRIVE-CLiQ

DQ01

S

Fanuc

Fanuc SerialInterface a

Fanuc aFanuc02

F

Fanuc SerialInterface ai

Fanuc ai

Fanuc05

High-speed, one-pair transmission
includes the a interface (normal andhigh speed, two-pair transmission)

Fanuc06

High-speed, one-pair transmission*) D epends on thedeviceBasics of functional safety
EnDat 2.2 strictly supports the use of
encoders in safety-related applications.
The basis for these are the standards
DIN EN ISO 13849-1 (successor to EN 954-1),
as well as EN 61508 and EN 61800-5-2.
In these standards, safety-related systems
are assessed based on criteria such as thefailure probabilities of integrated components
and subsystems. This modular approachhelps manufacturers implement theircomplete systems by allowing them tobuild upon previously qualified subsystems.

2)

Control
manufacturer1)

Comment

Normal and high speed, two-pairtransmission

Mitsubishi

Mitsubishi
high speed
interface

Mitsubishi

Mitsu01
Mit02-4
Mit02-2
Mit03-4
Mit03-2

M

Two-pair transmission
Generation 1, two-pair transmission
Generation 1, one-pair transmission
Generation 2, two-pair transmission
Generation 2, one-pair transmission

Yaskawa

Yaskawa
serial interface

Yaskawa

YEC02

Y

–

Panasonic SerialInterface

Panasonic

Panasonic

1)
2)

YEC07
Pana01
Pana02Compatible with YEC02
P–
Compatible with Pana01

For more information on the combination of an encoder and control, please contact the control manufacturer
The code letter is an add-on to the model designation of HEIDENHAIN encoders, such as in “LC 495 S.”

Further information:
See Functional Safety at
www.endat.de

Input circuit design of thedownstream electronics

Data transmission

Encoder

Downstream electronics

Dimensioning
IC1 = RS-485 differential line receiverand driver
Z0 = 120 

Incremental signals
Depends on the encoder(e.g., 1 VPP)

Further information:

1 VPP

FAQ: RS-485 transceiver atwww.endat.de10

11Position values
PROFIBUS DP serial interface

PROFIBUS DPPROFIBUS is a non-proprietary, open
fieldbus that conforms with the international
standard EN 50170. Using fieldbus systems
to connect sensors minimizes cabling andreduces the number of lines between theencoder and the downstream electronics.
Topology and bus assignment
PROFIBUS DP exhibits a linear structure
permitting transfer rates up to 12 Mbit/s.
Both mono-master and multi-mastersystems are possible. Each master canserve only its own slaves (polling). The
slaves are polled cyclically by the master.
Slaves can be sensors such as absoluterotary encoders and linear encoders, orthey can also be control devices such as
variable-frequency drives.
Physical-layer characteristics
The electrical characteristics of PROFIBUS
DP comply with the RS-485 standard. The
bus connection is a shielded, twisted-paircable with active bus terminations at bothends.

e.g., LC 115 absolute linear encoder

e.g., ROQ 437 multiturn rotary encoder
e.g., ROC 425 singleturnrotary encoder

PROFIBUS DP

e.g., variablefrequency drivewith motore.g., RCN 8001 absolute angle encoder
Bus structure of PROFIBUS DPPROFIBUS DP profile
The PNO (PROFIBUS user organization)
has defined standard, non-proprietary
profiles for the connection of absolute
encoders to PROFIBUS DP. High flexibility
and simple configuration are thereby
ensured for all equipment using thesestandardized profiles.

Functions of the DP-V0 classes

DP-V0 profile
This profile can be requested from the PNO
in Karlsruhe, Germany (ordering number:
3.062). There are two classes defined inthis profile: Class 1 is equivalent to theminimum range of functions, and Class 2
contains additional functions, some ofwhich are optional.
DP-V1 and DP-V2 profiles
The profiles can be requested from the
PNO in Karlsruhe, Germany (ordering
number: 3.162). These profiles likewise
distinguish between two device classes:• Class 3, with the basic functions, and• Class 4, with the full scaling and presetfunctionality.
In addition to the mandatory functions ofclasses 3 and 4, optional functions aredefined as well.

Characteristic
Data word width

Class

Rotational encoders
Linear encoders
1) 16 bits
 31 bits
 31 bits1)

Pos. value in pure binary code

1, 2







Data word length

1, 2

16

32

32

Scaling function  Measuring steps/rev.
   Total resolution

2
2







–
–

Reversal of counting direction 1, 2





–

Preset (output data: 16 bits
or 32 bits)

2







Diagnostic functions   Warnings and alarms

2







Operating time recording

2







Speed

2

 2)

 2)

–

Profile version

2







Serial number

2







1)

Initial setup
The data of the connectable HEIDENHAIN
encoders required for system configuration
are available for each encoder in the formof electronic device data sheets, commonlyreferred to as general station description
files (GSD). These general station description
files completely and unambiguously
describe the characteristics of a device in a
precisely defined format, thereby enabling
the convenient and application-friendly
integration of the devices into the bus
system.
Configuration
PROFIBUS DP devices can be configured
and the parameters assigned to fit therequirements of the user. These settings
are saved in the master once they havebeen selected in the configuration toolwith the help of the GSD file. As a result,
PROFIBUS devices are configured during
every network start-up. This simplifies
device replacement by eliminating the needfor editing or re-entry of the configuration
data.

Supported functions
Of particular importance in decentralized
fieldbus systems are diagnostic functions(e.g., warnings and alarms) and the electronic ID label, which contains information
about the encoder model, resolution, andmeasuring range. Also possible are programming functions, such as reversal ofcounting direction, preset/datum shift,and changing the resolution (scaling).
The operating time and the speed of theencoder can also be recorded.
PLC

Encoders with PROFIBUS DP
Absolute encoders with an integrated
PROFIBUS DP interface are connected
directly to the PROFIBUS fieldbus. The rearside of these encoders is equipped with
LEDs for indicating the operating status,
supply voltage, and bus status.
The coding switches for addressing (0 to 99)
and for activating the terminating resistor
are easily accessible under the bus cover.
The terminating resistor must be activated
if the rotary encoder is the final participanton the PROFIBUS DP fieldbus and if theexternal terminating resistor is not in use.

* With the EnDat interface2)

Functions of the DP-V1 and DP-V2 classes
Characteristic
Data word width

Class

Rotational encoders
 32 bits> 32 bits

Linear encoders

Telegram

3, 4

81-84

84

81-84

Scaling function

4





–

Reversal of counting direction 4





–

Preset / datum shift

4







Acyclic parameters

3, 4







Channel-dependent
diagnosis via alarm channel

3, 4







Operating time recording

3, 4



1)

 1)

 1)

Speed

3, 4



1)

 1)

–

Profile version

3, 4







Serial number

3, 4







1)

There are two GSD files to choose from:• GSD file for the DP-V0 profile• GSD file for the DP-V1 and DP-V2 profiles

12With a data word width > 31 bits, only the upper 31 bits are transferredRequires a 32-bit configuration of the output data and a 32 +16-bit configuration of the
input data

Not supported by DP-V2

13

PROFINET IO serial interface

PROFINET IO
PROFINET IO is the open Industrial Ethernet
standard for industrial communication. It
builds on the field-proven functional modelof PROFIBUS DP but uses fast Ethernet
technology as its physical transmission
medium, making it well adapted to the fasttransmission of I/O data. This standard also
provides the option of transmitting demanddata, parameters, and IT functions.

RCN 8000

IO device

PROFINET IO follows the provider-consumer
model, which supports communication
between Ethernet peers. One advantage isthat the provider transmits its data without
any prompting by the communication
partner.
Physical-layer characteristics
HEIDENHAIN encoders are connected to
PROFINET in accordance with 100BASE‑TX(IEEE 802.3, Clause 25) over one shielded,
twisted wire pair in each direction. The datatransfer rate is 100 Mbit/s (fast Ethernet).
PROFINET profile
HEIDENHAIN encoders generally satisfy thedefinitions as per Profile 3.162, Version 4.2.
This device profile describes the functionality of the rotary encoder. Class 4functions are supported (full scaling andpreset functionality). More information
about PROFINET can be obtained from the
PROFIBUS user organization (PNO).

14

IO device
Further fielddevices

Configuration
Profiles are predefined configurationsof the functions and performance
characteristics available from PROFINET
for use in certain devices or applications,such as in rotary encoders. They aredefined and published by the workgroups of
PROFIBUS & PROFINET International (PI).

PROFINET enables the connection ofdecentralized field devices to a controller.
It also describes parameterization,
diagnostics, and the exchange of data
between the controller and field devices.
The PROFINET design is modular.
Cascading functions can be selected by
the user himself. In order for the highspeed requirements to be met, thesefunctions primarily differ in terms of theirdata exchange type.
Topology and bus assignment
A PROFINET IO system consists of:• IO controller (control/PLC; controls
the automation task)• IO device (decentralized field device
such as a rotary encoder)• IO supervisor (development or
diagnostic tool such as a PC or
programming device)

IO device

Initial setup
In order for an encoder with the PROFINET
interface to be put into operation, a general
station description (GSD) file must be
downloaded and imported into the con­figuration software. The GSD file contains
the execution parameters required for a
PROFINET IO device.

PLC
IO controller

IO supervisor

LC 115

Supported functions

Class

Rotary encoders
Singleturn

MultiturnLinearencoders

Position value

3, 4







Isochronous mode

4







Functions of Class 4
Scaling function
Measuring units per revolution
Total measuring range	Cyclic operation (binary
scaling)
Acyclic operation
PresetCode sequence
Preset control G1_XIST1

4
4
4
4
4














–
–
–
–

4
4
4
4











–




Compatibility mode(encoder profile V.3.1)

3, 4







Operating time

3, 4







Speed

3, 4







Profile version

3, 4







Permanent storageof the offset value

4







Identification & maintenance(I & M)

External firmware upgrade







Profiles are important for openness,interoperability, and exchangeability,
assuring the end user that similar devices
from different manufacturers operate ina standardized manner.
Encoders or gateway with PROFINET
The encoders with integrated PROFINET
interface or the gateway are incorporated
directly into the network. Addresses areautomatically assigned via a protocol
integrated into PROFINET. A PROFINET IO
field device is addressed within a network
via its physical device MAC address. The
encoders feature two dual-color LEDs forbus and device diagnostics.
A terminating resistor for the final
participant is not needed.

15

SSI serial interface

The following functions can be activated
via the programming inputs of the interface
through application of the supply voltage UP:• Direction of rotation
The continuous application of a HIGH
level on PIN 2 (tmin > 1 ms) reverses the
direction of rotation for ascending
position values.
• Zeroing (setting to zero)
Application of a positive edge (tmin > 12 ms)
to PIN 5 sets the current position value
to zero (encoder must be at a standstill).
Warning: The programming inputs must
always be terminated with a resistor (seeInput circuit design of the downstream
electronics).

Control cycle for a complete data format
When not transmitting, the clock and datalines are held at HIGH level. The internallyand cyclically generated position value isstored on the first falling clock edge. The
data are transmitted on the first rising clockedge.
After transmission of a complete data
word, the data output line remains at
LOW level until the encoder is ready for a
new measured-value request (t2). Encoders
with the SSI 39r1 or SSI 41r1 interfaces
additionally require a subsequent clock
pause (tR). If another data-output request(CLOCK) is received within this time (t2 or
t2+tR), then the same data will be output
again.
If the data output is interrupted(CLOCK = HIGH for t  t2), then a newposition value will be stored on the next
falling clock edge. The downstream
electronics read the data at the next risingclock edge.

16

Interface

SSI serial

Ordering
designation

Singleturn: SSI 39r1
Multiturn: SSI 41r1

Data transmitted

Absolute position values

Data input

Differential line receiver in compliance with EIA standard RS-485
for CLOCK and CLOCK signals

Data output

Differential line driver in compliance with EIA standard RS-485
for DATA and DATA signals

Code

Gray code

Ascending position
valuesWith clockwise rotation as viewed from the flange side
(switchable via interface)

Incremental signals

Depends on the encoder» 1 VPP, TTL, HTL (see each type under Incremental signals)

Programming
inputsInactive
ActiveDirection of rotation and zeroing; for availability, see encoder
documentation
LOW < 0.25 · UP
HIGH > 0.6 · UP

Connecting cable

HEIDENHAIN shielded cables;e.g., PUR [(4 x 0.14 mm2) + 4(2 x 0.14 mm2) + (4 x 0.5 mm2)]
Max. 100 m
6 ns/mCable length
Signal propagationtime

T = 1 µs to 10 µs
tcal	See thespecifications
t1 	0.4 µs(without cable)
t2 =	17 µs to 20 µs
tR  5 µs
n =	Data word length
13 bits for ECN/ROC
25 bits for EQN/ROQ

Input circuit design of thedownstream electronics

Data transmission

Encoder

Downstream electronics

Dimensioning
IC1 = Differential line receiverand drivere.g., SN 65 LBC 176
LT 485Z0 = 120 
C3 = 330 pF (for improved noise immunity)

Programming via
connecting element(for availability, see theencoder documentation)

CLOCK and DATA not
shown

Permissible clock
frequency as afunction of cable
lengthIncremental signals
Some encoders also provide incremental
signals. These signals are primarily used forincreasing the resolution of the position
value or for providing data to a second
downstream device. They are almost always
1 VPP incremental signals. Exceptions are
identifiable based on the ordering
designation:• SSI41H With HTL incremental signals• SSI41T With TTL incremental signals

Incremental signals
e.g., 1 VPP

Data transmission

Clock frequency in kHz 

Starting with the Most Significant Bit (MSB),
the absolute position value is transmitted
over the data lines (DATA) at a clock speed
provided by the control (CLOCK). The SSIstandard data word length for singleturn
encoders is 13 bits, and for multiturnencoders, 25 bits. In addition to the absolute
position values, incremental signals canbe transmitted. For a signal description,
see Incremental signals.

Zeroing
Direction ofrotation

Cable length in m 

17The sinusoidal incremental signals A and
B are phase-shifted by 90° elec. and haveamplitudes of typically 1 VPP. The illustrated
sequence of output signals, with B lagging
A, applies to the direction of motion shownin the dimension drawing.
The reference mark signal R has a usable
component G of approx. 0.5 V. Next to thereference mark, the output signal can be
reduced by up to 1.7 V to a quiescent value
H. The downstream electronics must not
be allowed to overdrive on account of this.
Even at the low quiescent level, signal
peaks with amplitude G can appear.
The signal amplitude is valid when the
supply voltage stated in the specifications isapplied at the encoder. The signal amplitude
is based on a differential measurement
between the associated outputs at the
120 ohm terminating resistor. The signal
amplitude decreases when the frequency
increases. The cutoff frequency is thefrequency up to which a certain percentageof the original signal amplitude is maintained:• –3 dB  70% of the signal amplitude• –6 dB  50% of the signal amplitude

Interface» 1 VPP sinusoidal voltage signals

Incremental signals

Two nearly sinusoidal signals A and B
Signal amplitude M:			
0.6 to 1.2 VPP; typ. 1 VPP
Asymmetry |P – N|/2M:		
 0.065 (equivalent to 15°)
Amplitude ratio MA/MB:		
0.8 to 1.25
Phase angle |j1 + j2|/2:		
90° ±10° elec.

Reference marksignalConnecting cable
Cable length
Signal propagationtime

One or more signal peaks R
Usable component G:			
Quiescent value H:			
Signal-to-noise ratio E, F:		Zero crossovers K, L:			 0.2 V 1.7 V
0.04 V to 0.68 V
180° ±90° elec.

Measuring steps for position measurement
are recommended in the specifications.
Other resolutions are also possible for
special applications.

Short circuit at

20 °C

125 °COne output< 3 min< 1 minAll outputs< 20 s<5s

Cutoff frequency
Typical signal amplitude
curve as a function of
the output frequency(may vary depending on
the encoder)

Output frequency
–3 dB cutoff frequency–6 dB cutoff frequency

HEIDENHAIN shielded cables;e.g., PUR [4(2 x 0.14 mm2) + (4 x 0.5 mm2)]
Max. 150 m
6 ns/mThese values can be used for the dimensioning of the downstream electronics. Encoder
tolerances that are subject to constraints are listed in the specifications. For encoders
without an integral bearing, reduced tolerances are recommended for initial setup (seemounting instructions).
Signal period
360° elec.

The parameters in the signal description
apply to motion at up to 20% of the–3 dB cutoff frequency.
Interpolation/resolution/measuring step
The output signals of the 1 VPP interface
are usually interpolated in the downstream
electronics in order to attain sufficiently
high resolutions. For speed control,interpolation factors of greater than 1000
are normally used in order to provide
usable data even at low shaft speeds ortraversing speeds.

Short-circuit stability
The shorting of outputs is not a permissible
operating condition. Excepted from thisare encoders with a supply voltage of
DC 5 V ±5%, which do not fail if an output
briefly shorts to 0 V or UP.

Monitoring of the incremental signals
The following sensitivity levels arerecommended for monitoring the signal
amplitude M:
Lower threshold:0.30 VPP
Upper threshold:1.35 VPP

Incremental signal A

The amplitude of the incremenal signals
can be monitored based on the length ofthe position indicator arrow: the A and B
output singals are shown as a Lissajous
figure in the XY representation of theoscilloscope. Ideal sinusoidal signals
produce a circle with a diameter M. In thiscase, the position indicator r (shown) is
equivalent to ½M. The following formulaapplies:r = (A2+B2)Time 
Time HEIDENHAIN encoders with » 1 VPP
interface provide voltage signals that canbe highly interpolated.

Signal amplitude

Incremental signals» 1 VPP sinusoidal signals

Incremental signal B

Where: 0.3 V < 2r < 1.35 V(rated value)

A, B, R measured with oscilloscope in differential mode

Alternative
signal shape

Input circuit design of thedownstream electronics
Dimensioning
Operational amplifier (e.g., MC 34074)
Z0 = 120 
R1 = 10 k and C1 = 100 pF
R2 = 34.8 k and C2 = 10 pF
UB = ±15 V
U1 ≈ U0

Incremental signals
Reference mark signal

Encoder

Downstream electronics

Ra < 100 , typ. 24 
Ca < 50 pF
SIa < 1 mA
U0 = 2.5 V ±0.5 V(referenced to 0 V ofthe power supply)–3 dB cutoff frequency of the circuit≈ 450 kHz≈ 50 kHz with C1 = 1000 pF
			and C2 =	   82 pF
The circuit variant for 50 kHz does reducethe bandwidth of the circuit but also
improves its immunity to interference.
Output signals of the circuit
Ua = typ. 3.48 VPP
Gain: 3.48-fold18

19

 11 µASS sinusoidal signals

Input circuit design of thedownstream electronics forhigh signal frequencies
For high-accuracy encoders with a highsignal frequency, a special input circuit isnecessary.

Incremental signals
Reference mark signal

Encoder (e.g., LIP 281)

HEIDENHAIN encoders with » 11 µAPP
interface provide current signals. These
encoders are intended for connection to
ND digital readouts or EXE signal convertersfrom HEIDENHAIN.

Downstream electronics

Ra < 100 , typ. 24 
Ca < 50 pF
SIa < 1 mA
U0 = 2.5 V ±0.5 V(referenced to 0 Vof the power supply)

C0

RZ

R0

–3 dB cutoff frequency of the circuit
Various circuit variants are possible for the
input circuit, thereby allowing various cutoff
frequencies to be implemented. Dependingon the application and the encoder being
used, the receiver circuit may need to beadapted in order to achieve maximum
performance from the overall system.

UP

The sinusoidal incremental signals I1
and I2 are phase-shifted by 90° elec. andhave signal levels of typically 11 µAPP.
The illustrated sequence of output
signals—with I2 lagging I1—applies tothe direction of motion indicated in thedimension drawing (or to plunger retractionin the case of length gauges).

_
OP1
+

R0

Un
C0

RZ

The reference mark signal I0 has a usable
component G of approx. 5.5 µA.

Output signals of the circuit
The input circuit has been optimized for adownstream A/D converter with an input
range of 2 VPP. This yields a signal gain
factor of 1.21, resulting in an output voltage
Ua = 1.21 VPP for the A and B signals. The
signal gain factor for the R signal is 0.58.
Cutoff frequency –3 dB
500 kHz

2.5 MHz
R

A, B

5 MHz
R

A, B

10 MHzSignal

A, B

R

A, B

R

Ua

0V

0V

0V

0V

UP

+5 V

+5 V

+5 V

+5 V

Un

0V

0V

0V

0 V or –5 V

Z0*

127 

59.0 

133 

59.0 

133 

59.0 

133 

59.0 

R00

31.6 

0

31.6 

0

31.6 

0

31.6 

R1

1.21 k

681 

681 

681 

R2

1.47 k

825 

825 

825 

R3

1.82 k

464 

464 

464 

C0

220 pF100 pF

47 pF

22 pF

C1

68 pF

47 pF

22 pF

10 pF

OP1

e.g., THS452x

The signal amplitude is valid when the
supply voltage stated in the specifications
is applied at the encoder. It is based on adifferential measurement between theassociated outputs. The signal amplitudedecreases when the frequency increases.
The cutoff frequency is the frequency up towhich a certain percentage of the original
signal amplitude is maintained:• –3 dB cutoff frequency:
70% of the signal amplitude• –6 dB cutoff frequency:
50% of the signal amplitude

Interface» 11 µAPP sinusoidal current signals

Incremental signals

Two approximately sinusoidal signals I1 and I2
Signal amplitude M:			
7 to 16 µAPP; typ. 11 µAPP
Asymmetry |P – N|/2M:		
 0.065 (equivalent to 15°)
Amplitude ratio MA/MB:		
0.8 to 1.25
Phase angle |j1 + j2|/2:		
90° ±10° elec.

Reference marksignalOne or more signal peaks I0
Usable component G:			
Signal-to-noise ratio E, F:		Zero crossovers K, L:			

Connecting cable

HEIDENHAIN shielded cable
PUR [3(2 × 0.14 mm2) + (2 × 1 mm2)]
Max. 30 m
6 ns/mCable length
Signal propagationtime

2 µA to 8.5 µA
 0.4 µA
180° ±90° elec.

Signal period
360° elec.

Interpolation/resolution/measuring step
The output signals of the 11 µAPP interface
are usually interpolated in the downstream
electronics (ND digital readouts or EXE
signal converters from HEIDENHAIN) in
order to attain sufficiently high resolutions.

(rated value)e.g., AD8138* The resulting effective terminating resistance of the circuit is  120  for A, B, and R.

20

21 TTL square-wave signals

HEIDENHAIN encoders with the « TTL
interface contain electronics that digitize
sinusoidal scanning signals either with orwithout interpolation.

Interface« TTL square-wave signals

Incremental signals

Two TTL square-wave signals Ua1, Ua2 and their inverted
signals ¢, £The incremental signals are transmitted as
the square-wave pulse trains Ua1 and Ua2,phase-shifted by 90° elec. The referencemark signal consists of one or morereference pulses Ua0, which are gated with
the incremental signals. In addition, theintegrated electronics produce their inverted
signals ¢, £, and ¤ for noise-prooftransmission. The illustrated sequence of
output signals—with Ua2 lagging Ua1—
applies to the direction of motion shownin the dimension drawing.

Reference marksignalPulse width
Delay time

One or more TTL square-wave pulses Ua0 and their inverse
pulses ¤90° elec. (other widths upon request)|td|  50 ns

Fault-detection
signalPulse width

One TTL square-wave pulse ¥Fault detection: LOW (upon request: high-impedance Ua1/Ua2)
Proper functioning: HIGHtS  20 ms

Signal amplitude

Differential line driver as per EIA standard RS-422

Permissible load

Between associated outputs
Z0  100 		
|IL|  20 mA		Max. load per output
Cload  1000 pF
To 0 V
Outputs are protected against a short to 0 V

Switching times(10% to 90%)t+/t–  30 ns (typ. 10 ns)
with 1 m cable and specified input circuit

Connecting cable

HEIDENHAIN shielded cables;e.g., PUR [4(2 × 0.14 mm2) + (4 × 0.5 mm2)]
Max. 100 m (¥ max. 50 m)
Typ. 6 ns/m

The fault-detection signal ¥ indicatesmalfunctions such as breakage of thepower lines or failure of the light source.
In automated manufacturing, for example,
it can be used for machine switch-off.
The distance between two successive
edges of the incremental signals Ua1and Ua2 through 1-fold, 2-fold, or 4-foldevaluation is one measuring step.
The downstream electronics must be
designed to detect each edge of thesquare-wave pulse. The minimum edge
separation a stated in the specifications
is valid for the input circuit shown, in
conjunction with a cable length of 1 m,
and is based on a measurement at theoutput of the differential line receiver.
For the evaluation of the reference marksignal, the level of the reference marksignal is usually checked when signals Ua1and Ua2 are at HIGH level and are gatedwith the edge change at Ua1 or Ua2.

Note:
Not all encoders output a reference-marksignal, fault-detection signal, and inverted
signals. Please see the pin layout for this.

Cable length
Signal propagationtime

Signal period 360° elec.

Measuring step after
4-fold evaluation

The inverted signals ¢, £, and ¤ are not shown

Fault

Clocked output signals are typical of­encoders and signal converters with 5-foldinterpolation (or higher). The edge separation a of these signals is derived from an­internal clock source. At the same time, theclock frequency determines the permissible
input frequency of the incremental signals(1 VPP or 11 µAPP) and thus the resulting
maximum permissible shaft speed or­traversing speed:
anom =

1
4 · IPF · fenom

anom Nominal edge separation
IPF
Interpolation factor
fenom Nominal input frequency
The tolerances of the internal clock source
have an influence on the edge separation a of the output signal and the input
frequency fe, thereby influencing thetraversing speed or shaft speed.
For the stated edge separation, thesetolerances are already taken into account
at 5%; in each case, it is not the nominaledge separation that is stated, but rather
the minimum edge separation amin.
For the maximum permissible input frequency, however, a tolerance of at least 5%
must be taken into account. This meansthat the maximum permissible traversing
speed or shaft speed is also reduced­accordingly.
As a rule, encoders and signal converters
without interpolation have unclocked
output signals. The minimum edge
separation amin occuring at the maximum
permissible input frequency is stated in
the specifications. If the input frequency
is reduced, then the edge separation
correspondingly increases.
Cable-dependent differences in the
propagation time additionally reduce theedge separation by 0.2 ns per meter ofcable. In order to avoid counting errors, asafety margin of 10% must be taken into
account. The downstream electronics aredesigned such that they can still process
90% of the resulting edge separation.
Please note:
The maximum permissible shaft speed
or traversing speed must not be
exceeded—even temporarily—because
this will cause irreversible counting
errors.

22

Example calculation 1
LIDA 400 linear encoder
Requirements: display step: 0.5 µm; traversing speed: 1 m/s;
output signals: TTL; cable length to downstream electronics: 25 m.
What is the minimum edge separation that the downstream electronics must be able
to process?
Selection of the interpolation factor
20 µm grating period : 0.5 µm display step =				
40-fold subdivision
Evaluation of the downstream electronics				
4-foldInterpolation				 				 10-fold
Selection of the edge separation
Traversing speed 		
60 m/min (equivalent to 1 m/s)
+ tolerance value: 5%
63 m/minSelect in the specifications:
Next LIDA 400 version
120 m/min (from the specifications)
Minimum edge separation 0.22 µs (from the specifications)
Determining the edge separation that the downstream electronics must process
Subtract cable-dependent differences in the propagation time
0.2 ns per meter
For cable length of 25 m 						
5 nsResulting edge separation						0.215 µs
Subtract 10% safety margin						0.022 µs
Minimum edge separation for the downstream electronics 0.193 µs
Example calculation 2
ERA 4000 angle encoder with 32 768 lines
Requirements: measuring step of 0.1”; TTL output signals (IBV external signal
converter required); cable length from IBV to downstream electronics: 20 m;
minimum edge separation that the downstream electronics can process: 0.5 µs(input frequency: 2 MHz).
What shaft speed is possible?
Selection of the interpolation factor
32 768 lines corresponds to						Signal period of 40”: measuring step of 0.1” =			Evaluation of the downstream electronics				Interpolation in the IBV						Calculation of the edge separation
Permissible edge separation of the downstream electronics
This corresponds to 90% of the resulting edge separation
Therefore: resulting edge separation 				Subtract cable-dependent differences in the propagation time
For cable length of 20 m 						Minimum edge separation IBV 102 				a signal period of 40”
400-fold subdivision
4-fold100-fold
0.5 µs
0.556 µs
0.2 ns per meter4 ns
 0.56 µs

Selecting the input frequency
With the IBV 102, the input frequencies and thus the edge separation a are adjustable
as per the Product Information document.
Next suitable edge separation					0.585 µs
Input frequency at 100-fold interpolation 				4 kHzCalculating the permissible shaft speed
Subtract 5% tolerance 						This is 3800 signals per second, or 228 000 signals per minute.
With the 32 768 lines of the ERA 4000, the following applies:
Maximum permissible shaft speed 				3.8 kHz6.95 rpm

23

The permissible cable length for thetransmission of the TTL square-wave
signals to the downstream electronics
depends on the edge separation a. The
maximum cable length is 100 m or 50 m
for the fault detection signal. The required
supply voltage must be applied at theencoder (see the specifications). Over thesense lines, the voltage at the encoder
can be monitored and adjusted as neededby a suitable regulating device (remotesense power supply).

Permissible cable
lengthas a function of theedge separation

Cable length  HTL square-wave signals

HEIDENHAIN encoders with the « HTL
interface incorporate electronics that
digitize sinusoidal scanning signals with orwithout interpolation.

Without ¥With ¥

Edge separation

The incremental signals are transmitted
as the square-wave pulse trains Ua1 and Ua2,phase-shifted by 90° elec. The referencemark signal consists of one or morereference pulses Ua0, which are gated with
the incremental signals. In addition, theintegrated electronics generate the inverted
signals ¢, £, and ¤ for noise-immune
transmission (not with HTLs). The illustrated
sequence of output signals—with Ua2
lagging Ua1—applies to the direction of
motion shown in the dimension drawing.
The fault-detection signal ¥ indicatesmalfunctions such as a failure of the lightsource. In automated manufacturing, forexample, it can be used for machine
switch-off.

Input circuit design of thedownstream electronics
Dimensioning
IC1 = Recommended differential line
reciever:		 DS 26 C 32 AT
		 Only for a > 0.1 µs:
		 AM 26 LS 32
		 MC 3486
		 SN 75 ALS 193
R1 = 4.7 k
R2 = 1.8 k
Z0 = 120 
C1 = 220 pF (serves to improve noise
immunity)

Incremental signals
Reference mark signal

Fault-detection signal

Encoder

Downstream electronics

The distance between two successive
edges of the incremental signals Ua1 andUa2 through 1-fold, 2-fold, or 4-foldevaluation is one measuring step.
The downstream electronics must be
designed to detect each edge of thesquare-wave pulse. The minimum edge
separation a stated in the specifications
refers to a measurement at the output of
the stated differential input circuit. To prevent
counting errors, the downstream electronics
should be designed to still be able toprocess 90% of the edge separation a.

Interface« HTL, « HTLs
square-wave signals

Incremental signals

Two HTL square-wave signals Ua1, Ua2 and their inverted
signals ¢, £ (HTLs without ¢, £)Reference marksignalPulse width
Delay time

One or more HTL square-wave pulses Ua0 and their inverse
pulses ¤ (HTLs without ¤)90° elec. (other widths upon request)|td|  50 ns

Fault-detection signal One HTL square-wave pulse ¥Malfunction: LOW
Pulse width
Proper functioning: HIGHtS  20 ms
Signal levelUH  21 V at –IH = 20 mA
UL  2.8 V at   IL = 20 mA

With supply voltage
UP = 24 V, without cable

Permissible
loadMax. load per output, (except ¥)|IL|  100 mA		
Cload  10 nF		With respect to 0 V
Outputs can tolerate a short to 0 V and UP for a maximumof 1 min (except ¥)Switching times(10% to 90%)t+/t–  200 ns (except ¥)with 1 m cable and specified input circuit

HEIDENHAIN shielded cables;
22e.g., PUR [4(2 × 0.14 mm ) + (4 × 0.5 mm )]Cable lengthMax. 300 m (HTLs max. 100 m)
Signal propagation time 6 ns/m
Connecting cable

Fault

Signal period 360° elec.

The maximum permissible shaft speed
or traversing speed must never be
exceeded.

Measuring step after
4-fold evaluation

The inverted signals ¢, £, and ¤ are not shown

HTL

HTLs

Cable length 

The permissible cable length for incremental
encoders with HTL signals is dependent on
the output frequency, the supply voltage
being applied, and the operating temperatureof the encoder.

The current consumption of encoders
with HTL output signals depends on the
output frequency and the cable length tothe downstream electronics.
Output frequency 24

25

Other signals
Commutation signals for block commutation

Input circuit design of thedownstream electronics
HTL

Incremental signals
Reference mark signal

Encoder

Downstream electronics

The block commutation signals U, V,
and W are derived from three separate
tracks. They are transmitted as square-wave
signals in TTL levels.

Incremental signals
Reference mark signal« TTL square-wave signals

Commutation
signals
Width
Signal level

Three square-wave signals U, V, W and their inverted signals U, V, W

Incremental signals

See Incremental signals « TTL

Connecting cable

HEIDENHAIN shielded cables;
22e.g., PUR [6(2 x 0.14 mm ) + (4 x 0.5 mm )]Max. 100 m
6 ns/mCable length
Signal propagation
time

Fault-detection signal

HTLs

Interface

Encoder

Downstream electronics

2x180° mech., 3x120° mech., or 4x90° mech. (others upon request)
See Incremental signals « TTL

Commutation signals(values in mechanical degrees)

Fault-detection signal

26

27

Commutation signals for sine commutation

Limit switches

The commutation signals C and D are
obtained from the Z1 track and are equivalent
to one sine or cosine period per revolution.
They have a signal amplitude of typically
1 VPP at 1 k. The input circuit design ofthe downstream electronics is the same as
for the » 1 VPP interface. The required
terminating resistance Z0, however, is 1 k
instead of 120 .

Encoders with limit switches, such as
LIDA 400, are equipped with two limit
switches that make limit-position detection
and the formation of homing tracks
possible. The limit switches are activatedby differing adhesive magnets, thereby
permitting precise switching of the right orleft limit switches. The magnets can be
configured in series for the creation of
homing tracks.

Interface» 1 VPP sinusoidal voltage signals

Commutation
signals

Two nearly sinusoidal signals C and D
For the signal level, see Incremental signals » 1 VPP

Incremental signals

See Incremental signals » 1 VPP

Connecting cable

HEIDENHAIN shielded cables;e.g., PUR [4(2 x 0.14 mm2) + (4 x 0.14 mm2) + (4 x 0.5 mm2)]
Max. 150 m
6 ns/mCable length
Signal propagationtime

The signals from the limit switches are
output over separate lines and are thus
directly available.

LIDA 4xx
Output signals

HIGH/LOW level for each 1 TTL square-wave pulse forlimit switches L1 and L2

Signal amplitude

Collector stage with load resistance of 10 k against 5 V

Permissible load

IaL  4 mA
IaH  4 mA

Switching
Rise time
times
Fall time(10% to 90%)t+  10 µs
t–  3 µs
Measured with 3 m cable and recommended input
circuit design

Permissible cable lengthMax. 20 m

Electronic commutation with Z1 track
Output ofposition value
Analog switch

2

A/D converter

One revolution

Absolute position value
Coarse commutation

EEPROM andcounter

Z1 track

L1/L2 =	Output signals of
limit switches 1 and 2
Tolerance of the switching edge: ±2 mm

2Ⓢ = Beginning of measuring length ML
1 = Magnet N for limit switch 1
2 = Magnet S for limit switch 2

Incremental signals

Incremental signals

2Multiplexer

Reference mark signal

Subdivision electronics

Absolute position reference
Exact commutation

Input circuit design of the downstream
electronics

LIDA 400 limit
switches

Dimensioning
IC3 (e.g., 74AC14)
R3 = 1.5 k

+ 5V

+ 5V

10 k

LS

28

29

Position detection

In addition to having an incremental
graduation, encoders with position
detection, such as the LIF 4x1/LIP 60x1,
feature a homing track and limit switches
for limit position detection.
The signals are output in TTL levels overthe separate lines H and L, and are
therefore directly available.
With the LIP 60x1, fine adjustment of
the limit/homing position can also be
performed with the PWM 21.

LIF 4x1

LIF 4x1/LIP 60x1
Output signals

One TTL pulse each for homing track H and limit switch L

Signal amplitude

TTL
UH  3.8 V at –IH = 8 mA
UL  0.45 V at IL = 8 mA

Permissible loadR  680 
IILI  8 mA

Permissible cable lengthMax. 10 m; for LIP 60x1 during adjustment with PWM 21,
max. 3 m

LIP 60x1

 (ML + 10) 
ML
4

0.1
0.2 F



12
10

Ho 1.3
HomingLI

LI10.5*30

Limit switches
Homing track
LIF 400
LIP 6000r+5Ⓡ = Reference mark positionⓈ = Beginning of measuring length ML
LI = Limit mark, adjustableⒽ = Switch for homing track
Ho = Trigger point for homing

Input circuit design of thedownstream electronics
Dimensioning
IC3 (e.g., 74AC14)
R3 = 4.7 k

16.1

10

Ⓡ = Reference mark positionⓈ = Beginning of measuring length ML
LI = Limit mark, adjustableⒽ = Switch for homing track
Ho = Trigger point for homing

LI

Limit

LI20.5*

31

Further information
Signal converters

Signal converters from HEIDENHAIN enable
the flexible adaptation of interfaces forencoder signals to the requirements of yourapplication. Depending on the application,
additional signals (such as temperaturesensor signals) may be processed andtransmitted to the downstream electronics.

Input signals of the signal converters
HEIDENHAIN signal converters can beconnected to encoders with 1 VPP
sinusoidal signals (voltage signals) or
11 µAPP sinusoidal signals (current signals).
Encoders with the EnDat or SSI serialinterface can be connected to various
signal converters as well.
Output signals of the signal converters
The signal converters are available with thefollowing interfaces to the downstream
electronics:• TTL square-wave pulse trains• EnDat 2.2• DRIVE-CLiQ• Fanuc Serial Interface• Mitsubishi high speed interface• Yaskawa Serial Interface• PROFIBUS
Interpolation of the sinusoidal
input signals
In addition to performing signal conversion,
the signal converter also interpolates thesinusoidal encoder signals. This permits
finer measuring steps, resulting in higher
control quality and superior positioning
behavior.

Box design

Outputs

Interpolation1) or
subdivisionModel

Box design – IP65

5/10-foldIBV 101

20/25/50/100-fold

IBV 102

Without interpolation

IBV 600

25/50/100/200/400-fold

IBV 660 B

5/10-foldIBV 317120/25/50/100-fold

IBV 3271

5/10-fold

EXE 101

20/25/50/100-fold

EXE 1022-foldIBV 6072

5/10-foldIBV 6172

5/10-fold and20/25/50/100-fold

IBV 6272

Box design – IP65

 16 384-fold subdivision

EIB 192

Plug design – IP40

 16 384-fold subdivision

EIB 392

2

Box design – IP65

 16 384-fold subdivision

EIB 15121

Box design – IP65–

EIB 2391 S

Cable design – IP65–

EIB 3392 S

Box design – IP65

 16 384-fold subdivision

EIB 192 F

Plug design – IP40

 16 384-fold subdivision

EIB 392 F

2

Box design – IP65

 16 384-fold subdivision

EIB 1592 F

1

Box design – IP65

 16 384-fold subdivision

EIB 192 M

Plug design – IP40

 16 384-fold subdivision

EIB 392 M

2

Box design – IP65

 16 384-fold subdivision

EIB 1592 M

Interface

Quantity Interface

Quantity

« TTL

1

1

» 1 VPPPlug design

Plug design – IP40

» 11 µAPP« TTL/» 1 VPP(adjustable)

Cable design

Generation of a position value
Various signal converters feature an
integrated counter function. Starting fromthe last set reference point, an absolute
position value is generated and output tothe downstream electronics when thereference mark is crossed.

EnDat 2.2

DRIVE-CLiQ

Fanuc SerialInterfaceTop-hat rail design

Mitsubishi
high speed
interface

2

1

1

1

1

» 1 VPP» 1 VPPEnDat 2.2

» 1 VPP» 1 VPP

1

1

1

1

Box design – IP65

Box design – IP65

Yaskawa Serial 1
Interface

EnDat 2.2

1

Plug design – IP40–

EIB 3391Y

PROFIBUS DP 1

EnDat 2.2

1Top-hat rail design–

PROFIBUS
gateway

PROFINET IO

EnDat 2.2

1Top-hat rail design–

PROFINET
gateway

1)

32

Design – IP rating

Inputs1

Switchable

33

Testing and inspection devices, and diagnostics

HEIDENHAIN encoders provide all of theinformation needed for initial setup,monitoring, and diagnostics. The type of
information available depends on whether
the encoder is incremental or absoluteand on which interface is being used.

Overview

Incremental encoders have 1 VPP, TTL, or
HTL interfaces. TTL and HTL encoders
monitor their signal amplitudes internally andgenerate a simple fault detection signal.
With 1 VPP signals, an analysis of the output
signals is possible only with external testing
devices or through the use of computation
resources in the downstream electronics(analog diagnostics interface).
Absolute encoders use serial data transmission. Depending on the interface,­additional 1 VPP incremental signals can be
output. The signals are extensively monitored
within the encoder. The monitoring results(particularly valuation numbers) can betransmitted to the downstream electronics
along with the position values via the serialinterface (digital diagnostics interface).
The following information is available:• Error message: position value is not reliable• Warning: an internal functional limit of
the encoder has been reached• Valuation numbers:– Detailed information about the encoder’sfunction reserve– Identical scaling for all HEIDENHAIN
encoders– Cyclic reading capability
This enables the downstream electronics
to evaluate the current status of theencoder with little effort, even in closed
loop mode.
For the analysis of these encoders,
HEIDENHAIN offers the appropriate
PWM inspection devices and PWT testing
devices. Based on how these devices areintegrated, a distinction is made between
two types of diagnostics:• Encoder diagnostics: the encoder isconnected directly to the testing or
inspection device, thereby enabling adetailed analysis of encoder functions.
• Monitoring mode: the PWM inspection
device is inserted into the closed control
loop (via suitable testing adapters asneeded). This enables real-time diagnosisof the machine or equipment during
operation. The available functions dependon the interface.

34

PWT 101

Interface

Output signals(selection)

Encoderdiagnostics

Monitoring mode

Encoderdiagnostics

EnDat 2.1
(with incremental signals)

Position value
Incremental signals

Yes
Yes

No
Yes

Yes
Yes

EnDat 2.2
(without incremental signals)

Position value
Valuation numbers

Yes
Yes

Yes
1)
Yes

Yes
Yes

DRIVE-CLiQ

Position value
Valuation numbers

Yes
Yes

No
No

No
No7)

Fanuc

Position value
Valuation numbers

Yes
Yes

Yes
Yes

Yes
Yes8)

Mitsubishi

Position value
Valuation numbers

Yes
5)
Yes

Yes
Yes1) 5)

Yes8)
Yes8)

Panasonic

Position value
Valuation numbers

Yes
Yes

Yes
1)
Yes

Yes8)
Yes8)

Yaskawa

Position value
Valuation numbers

Yes
6)
Yes

No7)
No7)

Yes8)
Yes8)

SSI

Position value
Incremental signals

Yes
Yes

No
Yes

No
No

1 VPP

Incremental signals

Yes

Yes

Yes

11 µAPP

Incremental signals

Yes

Yes

Yes

TTL

Incremental signals
Scanning signals

Yes
4)
Yes

Yes
No

Yes
Yes4)

HTL

Incremental signals

Yes

2)

No

No7)

Commutation

Block commutation
Sinusoidal commutation

Yes
Yes

2)

No
Yes

Yes
Yes

Diagnostics with the PWM 21 and ATS software

Initial setup with the PWM 21 and ATS software

PWM 21

7)

8)

3)

1)

Information must be requested and transferred by the control
Via the appropriate signal adapter
3)
Only for encoders with block commutation (see encoder documentation)
4)
If supported by the encoder (PWT function)
5)
Not available for encoders with the ordering designation Mitsu01
6)
Not available for the EIB 3391Y
7)
Function not yet available
8)
Two-pair transmission is required (for more information, see the documentation for the PWT 100/PWT 101)
2)

35

PWT 101
The PWT 101 is a testing device for thefunctional testing and adjustment of
incremental and absolute HEIDENHAIN
encoders. Thanks to its compact andrugged design, the PWT 101 is ideal for
portable use.

PWT 101
Encoder input
only for HEIDENHAIN
encoders• EnDat 2.1 or EnDat 2.2(with or without incremental signals)• Fanuc Serial Interface• Mitsubishi high speed interface• Panasonic Serial Interface• Yaskawa Serial Interface• 1 VPP• 11 µAPP• TTL

Display

4.3-inch touchscreen

Supply voltage

DC 24 VPower consumption: max. 15 W

Operating temperature

0 °C to 40 °C

Protection EN 60529

IP20

Dimensions

Approx. 145 mm x 85 mm x 35 mm

Level display

PWT display

PWM 21The PWM 21 phase angle measuring unit,
in conjunction with the included ATS
adjustment and testing software, provides
an adjustment and testing package for the
diagnosis and adjustment of HEIDENHAIN
encoders.

PWM 21
Encoder input• EnDat 2.1 or EnDat 2.2(with or without incremental signals)• EnDat 3 (signal adapter may be needed)• DRIVE-CLiQ• Fanuc Serial Interface• Mitsubishi high speed interface• Yaskawa Serial Interface• Panasonic serial interface• SSI• 1 VPP/TTL/11 µAPP
• HTL (via signal adapter)

InterfaceUSB 2.0

Supply voltage

AC 100 V to 240 V or DC 24 V

Dimensions

258 mm × 154 mm × 55 mm

For more information, see the PWM 21,
ATS Software Product Information
document.

ATS
Languages

German, English, French, Italian, Spanish, Korean,Chinese (simplified), Chinese (traditional)

Functions• Position display• Connection dialog• Diagnostics• Mounting wizard for EBI/ECI/EQI, LIP 200, LIC 4000
and others• Additional functions (if supported by the encoder)• Memory contents

System requirements
and recommendations

PC (dual-core processor > 2 GHz)
RAM > 2 GB
Operating system: Windows 7, 8, and 10 (32-bit/64-bit)
500 MB of free hard drive space

DRIVE-CLiQ is a registered trademark of Siemens AG.

Mounting wizard
The PWM 21, together with the adjusting
and testing software (ATS), is recommended
for the mounting of exposed or multi-section
linear encoders or modular angle encoders.
If supported by the encoder interface, thePWT 101 can be used as well to a limited
extent.

Encoders*

Suitability of PWT 101

LIC 21xx, LIC 31xx, LIF 4xx, LIF 1xx,
LIDA 4xx, LIDA 2xx, ERM 2xxx



LIC 41xx, LIP 3xx, LB 3xx, LC 2xx,
PP 281, ECA 4xxx, ECM 24xx,
ERA 4xxx, ERA 7xxx, ERA 8xxx, ERP 880

Limited suitability: for optimal mounting
quality, please use the PWM 21 with the
ATS adjusting and testing software

LIP 2xx, LIP 6xxx, ERP 1xxx, ERO 2xxx

PWM 21 and ATS adjusting and testing
software required*Please read the notes in the encoder documentation

36

37

Measuring principles

Incremental measuring method
With the incremental measuring method,
the graduation consists of a periodic grating
structure. The position information is obtainedby counting the individual increments(measuring steps) from a chosen datum.
The shaft speed or traversing speed ismathematically derived based on the change
in position over time. Since an absolute
position is needed in order to deterine theabsolute reference, the measuring standards
feature an additional track that bears one
or more reference marks. The measuring
standard’s absolute position, as defined by
the reference mark, is assigned to exactly
one measuring step or signal period. As aresult, the reference mark must be scannedin order to establish an absolute reference or
in order to find the most recently selected
datum. In suboptimal cases, this may require
machine movements over large sections of
the measuring range. To make this easier,

General electrical information

many HEIDENHAIN encoders feature
distance-coded reference marks: thereference mark track contains multiplereference marks at different defined
distances. After two neighboring referencemarks have been crossed without achange in direction, the downstream
electronics can determine the absolutereference in less distance travelled. Scale
drums or encoders with distance-codedreference marks are designated withthe letter “C” at the end of the model
designation (e.g., for the TTR ERM 2200 C
and ERA 4200 C angle encoders, and the
LS 487 C linear encoder). With distancecoded reference marks, the absolutereference is calculated by counting theincrements between two reference marks
and using the formulas shown below.

Absolute measuring method
In the absolute measuring method, theposition value is available immediately upon
encoder switch-on and can be requestedby the downstream electronics at any time.
There is therefore no need to search forthe reference position by jogging the axes.
This absolute position information is readfrom the measuring standard, whichfeatures a serial code structure. To obtain
the position value, a separate incremental
track is interpolated.

Scope
The General electrical information applies to
HEIDENHAIN encoders, signal converters,
and cables. For any deviating information,
see the specifications. Throughout theGeneral electrical information chapter, theterm “encoders” refers to HEIDENHAIN
encoders and HEIDENHAIN signal
converters.

Power supply
Connect HEIDENHAIN encoders only todownstream electronics whose supply
voltage comes from PELV systems (for adefinition of terminology, see EN 60204-1).
Encoders meet the requirements of theIEC 61010-1 standard if power is supplied
from a secondary circuit with limited
energy (low voltage, limited energy) as per
IEC 61010-13rd Ed., Section 9.4, or from a
Class 2 secondary circuit as per UL1310.1)
When indicated in the certificate, encoders
that are certified for functional safety also
meet the requirements of the IEC 61800-5-3
standard if power if supplied from asecondary circuit with the relevant DVC A
voltag class.

Zeroposition

Linear encoders:Þ1 = (abs A–sgn A–1) x N + (sgn A–sgn D) x abs MRR
2
2

P1 = (abs R–sgn R–1) x N + (sgn R–sgn D) x abs MRR
2
2

and:

and:

A = 2 x abs MRR–N
GP

R = 2 x MRR–N

Definitions:Þ1 =	Absolute angular position of the first reference marktraversed relative to the zero position in degrees
abs = Absolute value
sgn =	Algebraic sign function (= “+1” or “–1”)MRR =	Measured value between the traversed reference marks
in degrees
N =	Nominal increment between two fixed reference marks(see tables)
360° )
GP = Graduation period (Line countD =	Direction of rotation (+1 or –1)
The rotation as per mating dimensions result in “+1”

Definitions:
P1 =	Position of the first traversed reference mark insignal periods
abs = Absolute value
sgn =	Algebraic sign function (“+1” or “–1”)MRR =	Number of signal periods between the traversed
reference marks
N =	Nominal increment between two fixed reference marks
in signal periods (see table below)
D =	Direction of travel (+1 or –1). Traverse of scanning unit
to the right (when properly installed) equals +1

38

However, the limits of the supply voltage
must not be violated by the ripple content.

The required supply voltage depends onthe encoder interface. A distinction is madebetween encoders without an extended
supply voltage range (e.g., DC 5.0 V ±0.25 V)
and those with an extended supply voltage
range (e.g., DC 3.6 V to 14 V).

The voltage values must be complied with at
the encoder. For encoders with an integrated
cable assembly, the voltage drop in thiscable assembly must be taken into account.
Further information (e.g., the cross sectionof the supply wires) must be taken fromthe encoder documentation as needed.
The voltage applied to the encoder can bemonitored and adjusted via the senselines, if present. If a variable power supply
unit is not available, then the voltage drop
can be reduced by connecting the senselines in parallel with the corresponding
supply wires.
When designing the power supply, use themaximum current or power consumption
according to the specifications.
For the sake of comparison and for inspection
purposes, the typical current consumption
and power consumption at typical ambientand operating conditions without load (onlysupply voltage connected) are specified forthe typical supply voltage or rated voltage.
This information is non-binding and subject
to change without notice.

Encoders with an extended supply
voltage range
For encoders with an extended supply
voltage range, the relationship between
the current consumption and the supply
voltage is non-linear. However, the power
consumption of the encoder exhibits anearly linear curve (see power consumption
and current consumption graph).
1) In place of IEC 61010-13rd Ed,
Section 9.4, the corresponding sectionsof the standards DIN EN 61010-1,
EN 61010-1, UL 61010-1, and
CAN/CSA-C22.2 No. 61010-1, can beused as well.

Current consumption and power consumption as a function of the
supply voltage (example)

Influence of the cable length on the power output of thedownstream electronics (example)

Power output of thedownstream electronics(normalized)

Angle encoders:

The voltage UP actually applied at the encoder
is to be considered when calculating thecurrent consumption and power
consumption of the encoder. This voltage
consists of the supply voltage UE provided
by the downstream electronics minus thevoltage drop U on the supply wires.

Power consumption and current
consumption (normalized)

A stabilized DC voltage UP is required for
powering the encoders. Information on
voltage and current consumption or power
consumption can be obtained from therespective specifications. Regarding theripple voltage of the DC power, the following
parameters apply:• High-frequency interference signal
UPP < 250 mV with dU/dt > 5 V/μs
• Low-frequency fundamental ripple
UPP < 100 mV

Supply voltage in V
Supply voltage in V

Encoder cable/adapter cable

Connecting cable

Total

Power consumption of encoder(normalized to value at 5 V)
Current consumption of the encoder(normalized to value at 5 V)

39

For this reason, the specifications provide
the maximum power consumption at theminimum and maximum supply voltage.
The maximum power consumption takes
the following factors into account:• The recommended receiver circuit• A cable length of 1 m• Age and temperature influences• Proper use of the encoder with respect
to the clock frequency and cycle time

If the value for the voltage drop U isknown, then the following parameters
can be calculated for the encoder anddownstream electronics: voltage at theencoder, current consumption of theenocder, power consumption of theenocder, and the power to be provided
by the downstream electronics.

For encoders with an extended supply
voltage range, the calculation of thevoltage drop U on the supply wires musttake the non-linear current consumption
into account. This occurs in three steps:

Current consumption of the encoder:
¹U
IM =
RL

Step 1: Resistance of the supply wires
The resistance of the supply wires (adapter
cable and connecting cable) can becalculated with the following formula:Power output of the downstream
electronics:
PE = UE · IM

Power consumption of the encoder:
PM = UP · IM

PMmax – PMmin+ UE
UPmax – UPminc = PMmin · RL +(UE – UPmin)

PMmax – PMmin· RL ·
UPmax – UPmin

Step 3: Voltage drop based on thecoefficients b and c¹U = 0.5 · (b – b2 – 4 · c)
Encoders without an extended supply
voltage range
For encoders without an extended supply
voltage range (typical supply voltage:
DC 5 V), the voltage drop U on the supply
wires is calculated as follows:

Definitions:
UP
Voltage at the encoder in V
IM	Current consumption of the encoder
in mA
PM	Power consumption of the encoder
in W
UE	Supply voltage at the downstream
electronics in VPE	Power output of the downstream
electronics in W
∆U	Voltage drop over the cable in V
LC
Cable length in metersAP 	Cross section of the supply wires
in mm2 (see cables)2		
Outgoing and incoming lines

Compliance with the supply voltage
at the encoder
The voltage drop may cause the supply
voltage to fall below its minimum permissiblelevel, particularly in the case of long cable
lengths and encoders with high current
requirements, such as absolute linear andangle encoders. The highest possible supply
voltage UP should therefore be selected in
the downstream electronics. The voltage
drop can be mitigated through the following
measures:• Keep thin cables with small wire crosssections as short as possible• For large cable lengths, select a wider
wire cross section• For downstream electronics without avariable power supply unit, connect thesense lines in parallel with the supply lines.
This doubles the available cross-section

The maximum overall length of the preassembled cables is provided in the tablebelow.
1.05	Length factor due to twisted wires
56
Electrical conductivity of copper
RL 	Resistance of the supply wires (forboth directions) in ohms
PMmin,
PMmax 	Maximum power consumptionin W at the minimum or maximum
supply voltage
UPmin,
UPmax 	Minimum or maximum supply
voltage in V of the encoder

EnDat 3
HMC 2
EnDat 2.2
HMC 6
DRIVE-CLiQ
Fanuc, Panasonic
Mitsubishi, Yaskawa
EnDat 2.1
SSI
1 VPP
11 µAPPTTL
1)

Encoder M to the downstream electronics E:

1.05 · LC∆U = 2 ∙     ∙IM ∙ 10–3
56 · AP

Data transfer technology
The transmission characteristics of the
pre-assembled cables, protocol propertiesof the interfaces, and other specifications
impose limitations on the design of thecable lengths.
Purely serial interfaces with transmission
frequencies of up to 16 MHz, in combination
with large cable lengths, place high technological demands on the cable. Thanks to a
design that is specially adapted to these­applications, HEIDENHAIN cables are highly
suitable for meeting these requirements.
For this reason, HEIDENHAIN recommends
using original HEIDENHAIN cables.
An adapter cable connected directly to theencoder is limited in terms of its length.
To implement larger cable lengths, anadapter cable and an additional connecting
cable with a larger cross section can be
used.

100 m
100 m
100 m
100 m
100 m
30 m1)
30 m
150 m
100 m
150 m
30 m
100 m

 engths of up to 50 m are possibleLdepending on the encoder

Please consider the specifications of thegiven encoder.

Signal converter between encoder M and downstream electronics E:

40

Maximum cable lengths
The cable lengths in the specifications
apply only to HEIDENHAIN cables and therecommended input circuit designs for thedownstream electronics. The maximum
attainable cable length is limited by thefollowing key factors:• Compliance with the supply voltage atthe encoder• Restrictions arising from thetransmission technology (e.g., protocol
design for purely serial interfaces andmanufacturer specifications for
proprietary interfaces)
Please note: These restrictions must be
checked independently from each otherand complied with.

1.05 · LC
56 · AP

Step 2: Coefficients for calculation of
the voltage dropb = RL ·Depending on the signal converter, acompensation factor for the efficiency of
the interface signal converter’s switching
power supply may have to be taken into
account (see the respective Product
Information document).

Cable lengths

Encoders

RL = 2 ·Voltage at the encoder:
UP = UE – ¹U

If a HEIDENHAIN encoder is operated ona downstream device via a HEIDENHAIN
signal converter, then the power
consumption of the encoder and thepower consumption of the signal converter
must be added to determine the resulting
power consumption.

Cable lengths for purely serial interfaces

41Additional connecting cable
Encoder
LC/RCN/ROC

Power consumption at
UP = 3.6 V or 14 V

Adapter cable  4.5 mm
AP = 2 x 0.16 mm2Pre-assembled cable  6 mm Pre-assembled cable  8 mm
AP = 2 x 0.16 mm2
AP = 2 x 0.35 mm2

3.6 V  1100 mW
14 V  1300 mW

20 m
6m
1m

15 m
29 m
34 m

ECN 1325

3.6 V  600 mW
14 V  700 mW

0.3 m

EQN 1337

3.6 V  700 mW
14 V  800 mW

0.3 m

3.6 V  950 mW
14 V  1050 mW

3m
1m

AK LIC 41x

Output cableinside themotor housing

35 m
66 m
77 m

65 m

99 m

55 m

99 m

Interface

Switch-on Maximum
time
voltage

1 VPP

1.3 s

Output cableon the encoder

37 m
39 m

85 m
89 m

Remarks:• These values apply to the supply voltage
UP = 4.9 V of the downstream electronics• Cable lengths may be limited dependingon the interface version of the encoder(see encoder data in the respective
brochure; maximum value = 100 m)• The stated power consumption values
apply only to the current edition of theInterfaces of HEIDENHAIN Encoders
brochure. For the currently valid power
consumption values, please refer to thespecifications in the relevant productbrochure.
• Please also consider the information of
the downstream electronics manufaturer
regarding the supply voltage for theencoder and the maximum permissible
cable lengths.

Transient response of supply voltage and switch-on/off behavior

UPmax
UPmin

UPP

0

5.5 V
Output signals invalid

11μAPP

Maximum cable length for purely serial interfaces (determined based on a supply voltage of DC 4.9 V)
A major factor influencing the attainablemaximum cable length is the supply voltageof the downstream electronics. At a supply
voltage of DC 12 V (±10%), overall lengthsof 100 m can be realized with HEIDENHAIN
connecting calbes for the encoders in thetable. The value selected for the table, 4.9 V,
represents the lower limit of the supply
voltage of commercially available downstream electronics. The table shows examples of adapter cable length combinations( 4.5 mm) for various encoders and theresulting maximum cable lengths of theconnecting cable. The values in the tableapply to a parallel connection of the senselines and the supply lines. The attainable
overall length is the sum of the lengths of
the adapter cable and connecting cable.

Switch-on/off behavior of the encoders
Valid output signals are available after theswitch-on time tSOT. During the time tSOT,
the output signals reach the maximum
voltage values stated in the table. The
duration of the switch-on time tSOT depends
on the interface.

Valid

Invalid

TTL
HTL

UPmax

EnDat

5.5 V

SSI

UPmax

PROFIBUS DP 2 s

5.5 V

PROFINET

UPmax

10 s

If the power supply is switched off, or if the
supply voltage falls below UPmin, then the
output signals are invalid as well. Furthermore,
the interface-specific switch-on/off characteristics must be taken into account. If the
HEIDENHAIN encoder is operated throughan interposing HEIDENHAIN signal converter,
then the signal converter’s switch-on andswitch-off conditions must also be taken
into consideration.

Other proprietary interfaces supported by
HEIDENHAIN are not dealt with here.

Power output of the downstream
electronics
For encoders with an extended supply
voltage range, the maximum power
consumption stated in the specifications
must be taken into account. Particularly inthe case of encoders with a supply voltage
of DC 5 V, be sure to note that the power
for the current consumption is indicatedwithout load. Therefore, keep in mind thatthe current consumption values will behigher depending on the design of thereceiver circuit. Losses in the adapter andconnecting cables must also be taken into
account.

Maximum current consumption at the
moment of switch-on
The increased current consumption must be
considered for the dimensioning of the power
pack. HEIDENHAIN therefore recommends
that the power pack be equipped with acurrent limit. The recommended value for thelimit is 400 mA, but at least 1.2 times thevalue of the maximum current consumptionof the encoder in steady state.

Design information regarding
the power pack of thedownstream electronics
Selecting the power supply of thedownstream electronics
Select a power supply that is as close as
possible to the upper tolerance limit.
Consider the voltage drop ¹U resulting
from the cable length. The power supply
should lie within the upper tolerance range,
particularly in the case of encoders with asupply voltage of DC 5 V ±0.25 V and
DC 5 V ±0.5 V. For encoders with a supply
voltage of DC 3.6 V to 14 V and functionalsafety, a supply voltage of DC 12 V isrecommended.

When dimensioning the current monitor
with switch-off (especially trigger threshold
and trigger speed), ensure that the increased
current consumption can be tolerated at
the moment of switch-on.

Note:
Depending on the encoder, other length
limitations may apply. For more information,
see the brochure and Product Information
document of the encoder in question.

42

43

The sum of the different signal propagation
times is referred to as the data age. It causes
a speed-dependent deviation of the determined position from the current physicalposition of the encoder.
Data age is determined by the signal
propagation times in the analog and digital
singal processing path of the encoder andthe downstream electronics, as well as the
propagation times in the transmission path.
Due to the characteristics of the interface,
the data age can be positive or negative.
For more information, refer to the encoder’sspecifications as needed (please consult
with HEIDENHAIN as needed).

Electrically permissible shaft
speed or traversing speed
The maximum permissible shaft speed or
traversing speed of an encoder is derived
from:• the mechanically permissible shaft speed
or traversing speed and• the electrically permissible shaft speed
or traversing speed.
In the case of incremental encoders withsinusoidal output singals, the electricallypermissible shaft speed or traversing speed
is limited by the –3dB/–6dB cutoff frequency
or the permissible input frequeny of thedownstream electronics.
For incremental encoders with square-wave
signals, the electrically permissible shaft
speed or traversing speed is limited by:– the maximum permissible scanning/
output frequency fmax of the encoderand– the minimum permissible edge separation a for the downstream electronics.

Scope
For angle or rotary encoders
nmax =

fmax∙ 60 ∙ 103z

As a supplement to the General electricalinformation, the following sections apply to
HEIDENHAIN encoders with a proprietaryinterface. For any deviating information,
see the specifications.

Operation Switchoff

For linear encoders–3

vmax= fmax ∙ SP ∙60 ∙ 10

Definitions:
nmax	Electrically permissible shaft speedin rpmvmax	Electrically permissible traversing
speed in m/min
fmax	Maximum scanning frequency /output frequency of the encoder
or the input frequency of thedownstream electronics in kHzz		Signal periods of the angle encoder
or rotary encoder per 360°
SP	Signal periods of the linear encoder
in μm

Encoders with the
DRIVE-CLiQ interface
Power supply
Encoders with the DRIVE-CLiQ interface aredesigned for a nominal voltage of DC 24 V.
The manufacturer of the downstream
electronics specifies DC 20.4 V to 28.8 V as
the tolerance for the supply voltage.
Encoders with the DRIVE-CLiQ interface
permit a larger voltage range (see the specifications). Operation at up to DC 36.0 V isbriefly permissible. In the range of DC 28.8 V
to 36.0 V, higher power consumption is to
be expected.
Switch-on/off behavior
Encoders with the DRIVE-CLiQ interface
are designed for the switch-on/switch-off
behavior shown in the upper-right diagram.
Cable lengths
The cable lengths indicated in the specifications apply only in the case of HEIDENHAIN
cables and the recommended input circuitdesigns for the downstream electronics.
The DRIVE-CLiQ interface permits amaximum cable length of 100 m, but thisvalue is reduced by a number of factors:• Number of dividng points with
DRIVE-CLiQ couplings• Length factor of the adapter orconnecting cable• Pluggable adapter cable at the encoder• Length of the HEIDENHAIN adapter
cable with compensation factor
The maximum permissible cable length for
DRIVE-CLiQ is determined as follows:Off

SwitchonStart-up

Ready for
operation
36 V (without limiting
functional safety)UP

Due to signal propagation times, deviations
from the current physical position of theencoder may arise• in the encoder(for serial interfaces)and• in the downstream electronics(for incremental interfaces).

Typ. 15 s(at the encoder)

Data age

28.8 VUP min.

tdU > 50 VdtsdU <−50 Vsdt> 100 ms
Uoff < 2 V

Switch-on/switch-off conditions for HEIDENHAIN encoders with the DRIVE-CLiQ interface

Definitions:nMG:	Influence of the encoder via aconnectable adapter cable, forexample; nMG = 1
4/3: 	Length compensation factor for
HEIDENHAIN adapter cables
LAC: 	Length of the HEIDENHAIN adapter
cable in m
ki: 	Length compensation factor1) of
the signal line i (4/3: for cables from
HEIDENHAIN)
Li:	Overall length1) of the signal line i
in mnC:
Number of dividing points
Encoders with the DRIVE-CLiQ interface
that are connected via an output cable(AGK) have an additional length limitation.
Due to the transmission characteristics ofthe output cables, a 40 m limit applies tothe formula for calculating the maximum
permissible cable length. This limit applies
to all output cables that have the designation“DQ01” in the “Use with” column of thecable overview list.

1) ee the specifications of the manufacturerSof the downstream electronics

Note:
Depending on the encoder, further
length restrictions may apply. For more
information, see the brochure or
Product Information document of thegiven encoder.
DRIVE-CLiQ is a registered trademark of
Siemens AG.

nMG · 5 m + 4 · LAC + Σ ki · Li + nC · 5 m  100 m
3
i

44

45

Electrical safety

Electromagnetic compatibility

HEIDENHAIN encoders must be supplied
from PELV systems (for an explanation ofterminology, see EN 60204-1); they arecertified in accordance with IEC 61010-1,
UL 61010-1, and CAN/CSA-C22.2
No. 61010-1.

Sources of electrical interferenceElectrical interference is primarily caused bycapacitive or inductive couplings. Inductive
couplings can arise on lines, as well as at
device inputs and outputs.
Typical sources of electrical interference
include the following:• Strong magnetic fields from transformers,
brakes, and electric motors• Relays, contactors, and solenoid valves• High-frequency equipment, pulse devices,and stray magnetic fields from switching
power supplies• Power cables and supply lines to theabovementioned devices

When indicated in the certificate, encoders
that are certified for functional safety also
meet the requirements of the IEC 61800-5-3
standard if power is supplied from asecondary circuit with the relevant DVC A
voltag class.
The housing of the encoders does notexhibit an electrical connection to internal
electric circuits. Encoders with exposed
electronics must be protected from damage
and the ingress of outside contaminationand liquids by means of a cover.

Conformity
If the measures listed below are complied
with, then HEIDENHAIN encoders fulfill
EMC Directive 2014/30/EU with regard to
the generic standards for the given area of
application:• Immunity
Specifically, the following standards:– ESD				EN 61000-4-2–	Electromagnetic fields
EN 61000-4-3– Burst			EN 61000-4-4– Surge			
EN 61000-4-5–	Conducted disturbances EN 61000-4-6–	Power frequency
magnetic fields		
EN 61000-4-8–	Voltage dips,
short interruptions		
EN 61000-4-11• Emission

Measures
The EMC Directive requires the attainmentof interference-free operation without theneed for EMC expertise. The following
measures serve to ensure this level ofinterference-free operation (please consult
with HEIDENHAIN as needed):• Properly install or mount encoders inaccordance with the mounting instructions.
• Use only original HEIDENHAIN cables.
Comply with the maximum permissible
cable lengths for the respective interface.
For usage that deviates from standard
usage (assignment of signals andconnectors), the manufacturer of thecomplete system must ensure conformity.
• Do not install cables in the immediate
vicinity of interference sources (inductive
consumers such as contactors, motors,
frequency inverters, solenoid valves, etc.)–S ufficient decoupling frominterference-signal-conducting cables
can usually be achieved by an air
clearance of 100 mm or, when cables
are in metal ducts, by a groundedpartition.
– A minimum clearance of 200 mm fromstorage reactors in switching power
supplies is required.
• Prevent accidental contact between theshield (e.g., connector) and other metalparts.

• For cables with an internal shield andexternal shield, connect the internal shield
to 0 V on the downstream electronics(exception: the hybrid motor cable from
HEIDENHAIN; see the documentationon the hybrid motor cable). Do not connect
the internal shield with the external shield.
• Use connecting elements (e.g., connectors
or terminal boxes) with metal housings.
These connecting elements may be used
only for the signals and supply voltage ofthe connected encoder (exception: thehybrid motor cable from HEIDENHAIN).
• Connect the encoder housing, connecting
elements, and downstream electronics
with each other by means of the cableshield. Connect the shield over a large area
along the complete circumference (360°).
For encoders with more than one electricalconnection, refer to the documentationof the respective product.
• Install encoders with exposed electronics
or a plastic housing in an enclosed metal
housing. If other signals and sources ofinterference will pass through the housing,then EMC expertise is required, and the
manufacturer of the complete system
must ensure conformity.
• Connect the (external) shield withfunctional earth in accordance with themounting instructions.

• For devices and cable assemblies withplastic connectors or connectors withouta large-area shield connection, connect
the (external) shield with functional earth
over a large area just a short distance
before the connector (shield clamp; seefigure). There must be no source ofinterference in the immediate vicinity.
• For encoders that optionally enable theconnection of an external sensor (e.g., atemperature sensor), conformity with the
EMC Directive applies only to operation
without an external sensor.
For operation with an external sensor(e.g., temperature sensor) strong EMC
expertise is required for interference-free
operation, and the manufaturer of theoverall system must ensure confromity:– Interference-free operation is possible
in most applications because thedisturbances acting on the sensor arelow.
– In addition, the requirements for theelectrical insulation of the sensor must
be considered because electricalhazards can arise from such systems.
• If compensating currents are to be
expected within the complete system,
then a separate equipotential bonding
conductor must be provided. The shield
is not meant to serve as an equipotential
bonding conductor.
• For encoders, provide high-frequency,
low-resistance grounding (see the
EMC chapter in EN 60204-01).

Minimum clearance from sources of interference

Shield clamp as substitute 0.3 m46

47

Mastering nanometer accuracy

DR. JOHANNES HEIDENHAIN GmbH
Dr.-Johannes-Heidenhain-Straße 583301 Traunreut, Germany +49 8669 31-0
 +49 8669 32-5061
info@heidenhain.dewww.heidenhain.com
1078628-23 · 1 · 12/2021 · CD · Printed in Germany

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