DBK43A and DBK43B

8-Channel Strain Gage Modules

Overview …… 1
Hardware Connection …… 3
Power Connection …… 3
Signal Connection …… 3

Hardware Configuration …… 4
Bridge Applications …… 5
AC Coupling and Low-Pass Filter Options …… 11
P1 Output Channel and Card Address Selection …… 12
DaqBook/100 Series & /200 Series and DaqBoard [ISA type] Configuration …… 12
DaqBook/2000 Series and DaqBoard/2000 Series Configuration …… 13

Hardware Adjustment …… 13
Trimpots …… 13
CAL/NORM, CAL1/RUN, and CAL2/RUN Switches …… 13

Software-Controlled Setup …… 14
Selecting Channel Types in DaqView, or <odes in LogView ……14
A Typical Setup Procedure with Embedded Examples ……16

GageCal, Calibration Program for DBK16, DBK43A, & DBK43B in Daq Applications ……21
Calibrating DBK16, DBK43A, & DBK43B for LogBook Applications ……25
Overview …… 25
Calibration Methods …… 26
Procedures Common to All Calibration Steps (Required) …… 27
Nameplate Calibration and Manual Calibration …… 30
Channel Calibration Procedure …… 33
2-Point Calibration …… 36
Shunt Calibration …… 38
Creating a Units Conversion Transfer Function …… 40
Periodic Calibration Without Trimpots …… 41

Specifications …… 42
Reference Notes:
o In regard to calculating system power requirements, refer to the section Power
Requirements in the DBK Basics section located at the beginning of the manual.
o Chapter 2, System Connections and Pinouts, includes pinouts for P1, P2, P3, andP4. Refer to the pinouts that are applicable to your system, as needed.
Note: Due to flexibility in configuration, please review the entire section before attempting setup andoperation.

Overview
The DBK43A and DBK43B will condition signals from most bridge-circuit transducers that have a signal
output of less than 50 mV. Strain gages and load cells are common types. We will use the terms:
module(s), gage module(s), and strain gage module(s) to refer to both units, except when a feature orfunction is exclusive to a specific module.
Primary Differences between the DBK43A and DBK43B
•
•
•
•
•

Time Stamping – Can be used with DBK43B; Stamping should not be used for DBK43A*
Event Marking – Can be used with DBK43B; Marking should not be used for DBK43A*
Input Signal Connectors – DBK43A uses a mini-DIN6 connector for each channel.
DBK43B uses a removable screw terminal block for each channel.
Calibration Switches – DBK43B has a two calibration slide switches (CAL1 and CAL2). The
DBK43A has one CAL/NORM switch.
Power LED – The DBK43A and DBK43B have different locations for the Power LED.

*In DBK43A – Time Stamping and Event Marking result in erroneous readings at the time of the stamping or marking.

DBK Option Cards and Module

899892

DBK43A & DBK43B, pg. 1

For half-bridge and quarter-bridge strain gages, the modules can accommodate usersupplied BCRs (bridge-completion resistors) that complete the bridge circuit. The bridge
circuit must be complete for the strain gage module to operate correctly.
Each channel of the strain gage module offers a selectable 3-pole, low-pass filter with a user-set cut-off
frequency. Remote-sense terminals are provided to make 6-wire Kelvin connections. Up to two modules
can be connected to each of 16 analog base channels for up to 256 input signals.

DBK43A and DBK43B Block Diagram
Note A: DBK43A uses Mini DIN-6 connectors for signal inputs. DBK43B uses removable screw-terminal blocks.
Note B: Channels 0 through 7 correspond with circuit board channels 100 to 800, as discussed in the Hardware
Configuration section.

Both strain gage modules provide an amplifier gain range of ×100 to ×1250 for use with strain gages having
0.4 to 10 mV/V sensitivities. Most strain gages are specified for a full-scale value of weight, force, tension,pressure, or deflection with an output of mV/V of excitation. For example, a strain gage with a full-scale rating of1000 lb of tension might output 2 mV/V of excitation at full load. With an excitation of 10 VDC, 1000 pounds ofload would produce an output of 20 mV.
The module’s 0 to 5 VDC offset and output-scaling permit nulling of large quiescent (inactive or motionless) loads
and expansion of the dynamic range for maximum resolution. Typically, the quiescent output is non-zero. Prior toa force being applied, a mounted strain gage can be in a state of partial deflection resulting in an output. In the caseof a tension gage, this output may be due to the weight of a hook or empty container.
The modules include an internal excitation voltage source. The wide-range excitation regulator is adjustable from
1.5 to 10.5 VDC with a current limit of 50 mA.

DBK43A & DBK43B, pg. 2899892

DBK Option Cards and Modules

Hardware Connection
Power Connection
The strain gage modules each require an input
voltage between +9 and +18 VDC. The DC
source should be filtered but not necessarily
regulated — a DBK30A Rechargeable
Battery/Excitation Module is recommended for
portable use. The DBK43A and DBK43B strain
gage modules have an isolated DC/DC converterbased power supply which provides all excitation
voltages and biasing for the amplifier circuits.
For both modules, each of eight on-board
excitation regulators can be adjusted from 1.5 to10.5 VDC. These outputs have remote sensing terminals and feature 50 mA current limiting to prevent
damage from short-circuit or overload. The regulators’ wide voltage range can accommodate any resistive
or semi-conductive gage type.
The DBK43A and DBK43B can be powered with an AC adapter or from any isolated 9-18 VDC source of
16 W (see figure). Before plugging unit in, make sure the power switch is in the “0” (OFF) position.
If using an AC power adapter, plug it into an AC outlet and attach the low voltage end to the jackon the DBK43A or DBK43B, as applicable.
If using a different 9 VDC to 18 VDC source, make sure the leads are connected to the proper
DIN terminals. Power connections for DBK43A and DBK43B are the same.

CAUTION
POWER IN : The power connectors are rated at 5 amps maximum DC current. The
power supply provided with the module can power the unit but not any auxiliary
devices. If using the unit’s power supply, do not use the POWER OUT terminal.
If using another power supply to power auxiliary devices from the POWER OUT
terminal, make sure that power supply is current-rated for the units connected(up to 5 amps DC).
POWER OUT : Maximum output current is 3 amps DC. Use a power supply capable ofsupplying 5 amps DC at POWER IN.

Signal Connection
CAUTION
The maximum channel signal input from plus Voltage (+V) to minus Voltage (-V) is
50 mV. There is no common-mode isolation between inputs (common-mode voltage
between inputs must be 0 V).
The following two figures (next page) each represent one of the 6-pin signal connectors located on theback of a DBK43A (left figure) and DBK43B (right figure). Both configurations are for a full-bridge withremote sensing.

DBK Option Cards and Module

899892

DBK43A & DBK43B, pg. 3

DBK43A uses a mini-DIN6 connector with pre-defined wire color coding based on a CA-132 cable. Colorcoding of wires for DBK43B is user-defined.
Pin 1

Pin 2

Pin 3

Pin 4

Pin 5

Pin 6

DBK43A- Sense- Exc.

-V+V+ Exc.

+ SenseDBK43B+ Sense- Sense+V-V+ Exc.

- Exc.

DBK43A Connection Example
Full-Bridge with Remote Sensing*Colors in this schematic are determined by the Mini-DIN6
connector pin and the color code of the CA-132 cable.

DBK43B Connection Example
Full-Bridge with Remote Sensing
Colors in this schematic are arbitrary.
Actual wiring color is user defined.

The connectivity aspect of DBK43A and DBK43B differs, as indicated in the two wiring
diagrams. Be sure to use the correct diagram for your specific hardware.
The DBK43B pinout and diagram above supersede the one found in the DBK Option Cards
and Modules User’s Manual rev 8.2.

Hardware Configuration
Factory Defaults:
Bridge configuration: Full
Coupling: DC
Low pass filter: Disabled (bypassed)
Unless special arrangements have been made, the cutoff frequency is disabled (bypassed) when
the strain gage module is shipped from the factory. If the low pass filter is enabled it will have adefault value of 3.7 Hz.* You can enable the low pass filter [on an individual channel basis] byorienting the associated channel’s Filter Jumper (JP104 for channel 0 through JP804 for channel
7) to the vertical position. Refer to the following board layout in regard to jumper location andorientation.
*DBK43A and DBK43B are shipped with a 100 kΩ resistor in each of eight channel filter locations. The
resistors are installed in locations R105-106-107 through R805-806-807 (for channels 0 through 7
respectively). Refer to the following board layouts.

Configuration options:
Bridge Applications using various bridge-completion resistors and jumpers
AC Coupling and Low-Pass Filter Options
P1 Output Channel and Card Address Selection
The following board layout can be referred to for jumper, switch, and resistor locations.

DBK43A & DBK43B, pg. 4899892

DBK Option Cards and Modules

CH7
Power
LED

CAL1 CAL2

CH6

CH5

CH4

CH3

CH2

CH1

CH0

DBK43B Board (Rear Panel Section)**

DBK43B (Rear Panel)**** With exception of the rear panel area, the DBK43B has the same board layout as the DBK43A. On the DBK43B the PowerLED is located between the Power switch and the Power In connector. Another difference is that the DBK43B has a two
calibration slide switches (CAL1 and CAL2). The DBK43A has one CAL/NORM switch. In regard to channel connectors,
DBK43B employs removable screw terminal blocks; DBK43A uses mini-DIN6 connectors.
DBK Option Cards and Module

899892

DBK43A & DBK43B, pg. 5

Bridge Applications
There are several ways to hook-up strain gages—all are configured into a 4-element bridge (the 4 legs in a
bridge circuit). The quarter-, half- or full- designation for a strain gage refers to how many elements in thebridge are strain-variable.
quarter bridges - have 1 strain-variable element
half bridges - have 2 strain-variable elements
full bridges - have 4 strain-variable elements
DBK43A and DBK43B boards include a silkscreen pictorial aid, as indicated in the following figure. On
the boards, the image appears between the channel inputs and Headers H100 through H400.

FULL BRIDGEDEFAULT

FULL BRIDGEWITH REMOTE
EXCITATION SENSING

3 WIRE QUARTER
BRIDGE

3 WIRE QUARTER
BRIDGEFULL BRIDGEWITH REMOTESHUNT CAL RESISTOR

On-Board Silkscreen Aid for Configuring Jumper Headers H100 through H800.
Each channel of the strain gage module has locations for bridge-completion resistors when using quarterand half-bridge strain gages. These resistors are fixed values necessary to fill out the 4-element bridge
configuration.
The following is a standard symbol for a 4-element bridge type strain gage. The figure makes use ofbridge-completion resistor designations for a module’s channel.
Any or all of the 4 resistive elements may be strainvariable. Where an element is a fixed resistor, thefixed resistor may be installed in the internal location
provided. Note that n is the channel number +1.
For an internal resistor on channel 7, the location is
R800E.
If R1-R4 is a fixed resistor it may be placed internally in the Rnlocations on the resistor plug. “n” is the channel number + 1.
R1 = Rn00F; R2 = Rn00C; R3 = Rn00E; R4 = Rn00B.
Example: R3 in channel 7 = R800E location.

Bridge Completion Resistors

Connections are provided for Kelvin-type excitation.
The excitation regulators stabilize the voltage at the
points connected to the on-board sampling dividers.
Unless you run separate sense leads to the excitation
terminals of the strain gage, the voltage regulation ismost accurate at the terminal blocks on the DBK43A
or DBK43B. In a Kelvin-type connection, six wires
run to a 4-element strain gage, and the excitation
regulation is optimized at the strain gage rather than at
the terminal blocks. This connection works with aslittle as 10 feet of 22 gauge lead wire if accuracy is
critical. (See Full-Bridge with Remote Excitation
Sensing Configuration in full-page figure.)
Kelvin-type Excitation Leads

DBK43A & DBK43B, pg. 6899892

DBK Option Cards and Modules

The Kelvin connection using the remote sensing lines performs best when the entire bridge is localized(no bridge-completion resistors inside the DBK43A or DBK43B) and all leads are contained in a multiconductor cable. If individual wire leads are used, the two sense wires should be tightly twisted to form apair. Likewise, the two excitation wires and the two bridge-output wires should be twisted together).
The internal excitation source is attached to a voltage regulator in the strain gage module’s circuitry. The
regulator provides the excitation to the actual transducer (there is a separate regulator for each transducer,
hence 8 regulators per strain gage module). Each regulator has a maximum current of 50 mA. The
maximum excitation voltage that can be provided by the module’s excitation regulator is:
VMAX[EXC] = 0.05 × R(where R = the resistance in ohms of 1 element in the bridge circuit).

CAUTION
Setting the excitation voltage above the maximum voltage allowed can cause theDBK43A or DBK43B to fail. The maximum allowable excitation voltage is determinedby the following equation.
VMAX[EXC] = 0.05 x R
R is the resistance in ohms of 1 element in the bridge circuit.
The following full-page figure shows various strain-gage configurations.

DBK Option Cards and Module

899892

DBK43A & DBK43B, pg. 7

Bridge Configuration Settings for DBK43A and DBK43B

DBK43A & DBK43B, pg. 8899892

DBK Option Cards and Modules

Input Configuration Headers
Eight 2×6 pin-headers with pin numbers 1 to 12 are on the board, 1 for each channel designated H100 (channel 0) to
H800 (channel 7). The user can position jumpers on this header to configure inputs from a variety of bridge types.
Jumping header pins 1-to-2 and 3-to-4 connects the +Vin and -Vin to the calibration MUX for different
bridge configurations.
Jumping pins 5-to-7 and 9-to-11 allows internal sense regulation of the excitation regulator.
Jumping pins 5-to-6 and 11-to-12 allows for remote excitation sensing.
Jumping pin 10-to-12 allows the use of a remote shunt-calibration resistor.
See previous figure for header configurations that correspond with different bridge-wiring schemes.

Resistor Sockets and Adapter Plugs
Eight 2×8 resistor sockets with rows numbered A to H are on the board; 1 socket for each channel and designatedR100 (channel 0) to R800 (channel 7). An adapter plug for soldering resistors is included for each channel; usersoldered plugs facilitate changing configurations as needed.
Bridge-completion resistors include: Rn00B, Rn00C, Rn00E, and Rn00F. Resistors Rn00A and Rn00G areused to complete 3-wire strain-gage configurations.
Rn00D and Rn00H are internal shunt resistors from +V in and -V in respectively to -excitation.
Match the proper row as shown in the figure, Bridge-Configuration Settings
for DBK43A and DBK43B (previous page).
DO NOT just insert resistors into sockets. Such connections are unreliable.
To achieve a reliable connection, solder resistors to the adapter plug
Soldering should be done with the plug inserted into the resistor socket;
otherwise, heat from soldering can distort the shape of the plug.
After soldering, the resistor leads should be snipped off close to the support
to prevent contact with other components.
Handle the adaptor plugs with care to prevent pin damage.

Shunt-Calibration Resistors
DBK43A and DBK43B provide physical locations for internal shunt-calibration resistors. Each channel has resistor
locations that can be shunted across one or the other of the lower bridge arms by a hardware and software-accessible
solid state switch (FET transistor) to create a repeatable bridge imbalance with a precision resistor.
For any balanced bridge, a resistance value can be applied in parallel with one of the four bridge elements to createa predictable imbalance and output voltage. For example, a 350Ω 2mV/V strain gage will deliver full output if one
arm drops by 0.8% (about 2.80Ω) to 347.2Ω. A 43.4 KΩ resistance shunted across one or the other lower bridge
elements will result in full-positive (Rn00H) or full-negative (Rn00D) output. For best results, Rn00H and Rn00D
should be across the strain element when it is switched in.

DBK Option Cards and Module

899892

DBK43A & DBK43B, pg. 9

A formula used to calculate the shunt-cal resistance value is:

RShunt = [RGage / FG(ε) ] - RGage
Where:

RShunt = the shunt calibration resistor value
RGage = the resistance of the gage
FG = the gage factor
ε = the strain value of the gage
Example:An engineer wants to know the shunt calibration resistor value for a strain gage with the following
parameters.
resistance: 120 Ω
gage factor: 2.0
strain: 5000 micro-strain, i.e., 5000 x 10-6
Plugging the values into the equation, we get:

RShunt = [RGage / FG(ε) ] - RGage= [120 / 2.0(5000 x 10-6)] - 120= [120 / .01] – 120= 12000 – 120= 11,880 Ω
In all cases, the resistance of the solid-state switch will be negligible when compared to the shunt
resistance. Changing the CAL/NORM switch (on the rear panel) to the CAL position while reading thebridge will activate the shunt-calibration resistors. After reading the offset, return the switch to the NORM
position for normal bridge readings.

DBK43A & DBK43B, pg. 10899892

DBK Option Cards and Modules

AC Coupling and Low-Pass Filter Options
Per channel, the strain gage modules each accommodate coupling and low-pass filter options including:•

AC-coupling or DC-coupling•

Using or bypassing the filter•

Choice of the filter’s corner frequency via a SIP resistor network•

Filter gain (default of ×2 can be changed to ×1).

The AC-coupling or DC-coupling choice on each channel is set by the presence orabsence of shunt jumpers on 2-pin headers. If the shunt jumper is in place, thecoupling is DC. If the shunt jumper is absent, the coupling is AC. See table forchannels and corresponding headers.

Channel
0
1
2
3
4
5
6
7

Header
JP103
JP203
JP303
JP403
JP503
JP603
JP703
JP803

The choice of using or bypassing the low-pass filter for each channel is made by theorientation of two shunt jumpers on a 2×2 pin header. When the shunt jumpers areoriented horizontally (like the “bypass” symbol on the circuit board) the filter is
bypassed. When the shunt jumpers are oriented vertically (like the “filter” symbol),the filter is in the signal path.

Channel
0
1
2
3
4
5
6
7

Header
JP104
JP204
JP304
JP404
JP504
JP604
JP704
JP804

Channel
0
1
2
3
4
5
6
7

Resistors
R105-R106-R107
R205-R206-R207
R305-R306-R307
R405-R406-R407
R505-R506-R507
R605-R606-R607
R705-R706-R707
R805-R806-R807

Resistance (Ω)
10
20
50
100
200
500
1K
2K
5K
10K
20K
50K
100K

Bourns P/N
4606X-102-100
4606X-102-200
4606X-102-500
4606X-102-101
4606X-102-201
4606X-102-501
4606X-102-102
4606X-102-202
4606X-102-502
4606X-102-103
4606X-102-203
4606X-102-503
4606X-102-104

The corner frequency of a low-pass filter is determined by three resistor
values in each filter circuit. The resistors are listed in the following table.
These resistor locations have been physically arranged to allow the use of a
6-pin SIP network as a convenient means of changing all 3 resistors. The
machined-pin socket will also allow you to insert individual resistors.

The next table is a list of some common frequencies, thenominal resistance value, and a Bourns part number for asuitable network.

Frequency
133kHz66.7kHz
26.6kHz
13.3kHz
6.67kHz2.66kHz
1.33kHz
667Hz
266Hz
133Hz
66.7Hz26.6Hz13.3HzThe active low-pass filters have a gain of ×2. This gain can be factored into the setup
calculations, or the filter gain can be changed to ×1. To change the gain to ×1 (unity)
for the corresponding channels, de-solder (or snip leads) and remove the resistors
shown in the table.
Note: The default ×2 gain option meets the needs of most applications.

DBK Option Cards and Module

899892Channel
0
1
2
3
4
5
6
7

R (10K)
R144
R244
R344
R444
R544
R644
R744
R844

DBK43A & DBK43B, pg. 11

P1 Output Channel and Card Address Selection
All 8 channels on the strain gage module are multiplexed into 1 of the LogBook or Daq Device basechannels (0 to 15). The base channel (that the DBK43A or DBK43B is multiplexed into) is set by theshunt jumper on the 16×2 header designated JP1.
Each base channel can have up to 16 expansion channels multiplexed into it. Since the strain gage module
represents 8 expansion channels, two modules can be multiplexed into each LogBook base channel. To
distinguish channels, there is a 3-pole header (designated J2) with a shunt jumper that can be placed in oneof two positions for either LOWER (0 to 7) or UPPER (8 to 15) expansion channels.
With the LogBook or Daq device’s 16 base channels, up to 32
DBK43A [or DBK43B] modules can be used for a maximum of 256
channels. These channels are identified differently in the API for
custom programming and in DaqView and GageCal.
For the API, the base channels are designated 0 to 15; and expansion
channels are designated 16 to 271. Channel 16 is the first channelon the first expansion board (for DBK43A and DBK43B channel 0
on lower module with JP1 set to CH0) and channel 271 is the lastchannel on the last expansion board (for DBK43A [and DBK43B],
channel 7 on upper module with JP1 set to CH15). The table shows
the base channel and the first expansion channel number (N)associated with that particular base channel. To calculate the actual
input channel, add “N” to “n”. (If J2 is set to LOWER, the n-values
for input channels 0 to 7 range from n = 0 to n = 7; if J2 is set to
UPPER, the n-values range from n = 8 to n = 15.) This expansion
channel number is also needed when writing a program to read fromthat particular channel.

Daq Device
Base
Channel
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15

First Expansion
Channel Number (N)
16
32
48
64
80
96
112
128
144
160
176
192
208
224
240
256

For DaqView , LogView and GageCal, these same 256 channels are identified from ch0-0-0 to ch15-2-7.
The first field (0 to 15) is the base channel; the second field is the lower (1) or upper (2) sub-channel
selected on J2; and the third field (0 to 7) is the 8 channels on a single DBK43A or DBK43B module.
Reference Note:
For more information on channel multiplexing, refer to Chapter 1, Signal Management.

DaqBook/100 Series & /200 Series and DaqBoard [ISA type] Configuration
Use of the DBK43A or DBK43B requires setting jumpers in DaqBooks/100 Series & /200 Series devices

and ISA-type DaqBoards.
1.

If not using auxiliary power, place the JP1 jumper in the expanded analog mode.

Note: This default position is necessary to power the interface circuitry of the DBK43A [or DBK43B]
via the internal ±15 VDC power supply. If using auxiliary power (DBK32A or DBK33), youmust remove both JP1 jumpers. Refer to Power Management in the DBK Basics section [at thefront of the manual] and to the DBK32A and DBK33 document modules as needed.

DBK43A & DBK43B, pg. 12899892

DBK Option Cards and Modules

2.

For DaqBook/100, DaqBook/112 and DaqBook/120, place the JP4 jumper in single-ended mode

Note: To use a DBK43A [or DBK43B] with a Daq PC-Card, you must an appropriate power module must
be used.

DaqBook/2000 Series and DaqBoard/2000 Series Configuration
No Jumper configurations are required for these /2000 series devices.

Hardware Adjustment
Bridge circuit transducers are used for many different applications, and the DBK43A and DBK43B
modules are flexible enough to support most of them. Each channel circuit has an excitation regulator, ahigh gain (100-1250) input amplifier with offset adjustment, a low-pass filter, a scaling (1-10) amplifier,and a calibration multiplexer.

Trimpots
The front of the strain gage modules have a slot to allow access to 4 potentiometers to trim (adjust) the
accuracy for each channel circuit. The trimpots are labeled to represent the following adjustments:
EXC
for adjusting the excitation voltage to the transducer
GAIN

for setting the gain of the input amplifier

OFFSET for adjusting the circuit offset for quiescent loads or bridge imbalance
SCALE

for setting the gain of the scaling amplifier
Channel Number

Trimpot
CH0

CH1

CH2

CH3

CH4

CH5

CH6

CH7

EXC

TP101

TP201

TP301

TP401

TP501

TP601

TP701

TP801

GAIN

TP104

TP204

TP304

TP404

TP504

TP604

TP704

TP804

OFFSET

TP103

TP203

TP303

TP403

TP503

TP603

TP703

TP803

SCALE

TP105

TP205

TP305

TP405

TP505

TP605

TP705

TP805

The following figure shows trimpot locations for both the DBK43A and DBK43B.

Trim Pot Locations

CAL/NORM, CAL1/RUN, and CAL2/RUN Switches
DBK43A has a single CAL/NORM switch. DBK43B has two switches, CAL1/RUN and CAL2/RUN.
The switches are easy to see on the rear panel of the associated DBK module.
•

The NORM and RUN positions are for normal running operations, as indicated in the following
tables.

•In the CAL position, the shunt calibration offset and the excitation voltage can be read depending on
the software function control. This is discussed in the next section.

DBK Option Cards and Module

899892

DBK43A & DBK43B, pg. 13

Software-Controlled Setup
Proper setup includes the use of software to control the calibration multiplexer in each circuit. The calibration
multiplexer is used to switch the bridge circuit out and apply internal reference voltages to the input for use in
the DBK43A or DBK43B setup. The calibration multiplexer also allows the recording of the individualadjustments.
The next two tables identify functions available through DaqView and LogView, respectively. Note that
DaqView uses the term “Channel Type;” and LogView uses the term “Mode.” The tables include equations
in which “VOUT” (voltage out) represents the voltage recorded by the primary data acquisition device, i.e., a
LogBook, DaqBook, DaqBoard, or other Daq device.

Selecting Channel Types in DaqView, or Modes in LogView
Reference Notes:
Typical setup steps with embedded examples begin on page 16 of this DBK43 document.
The steps can be used for both LogBook and Daq device applications.

Selecting Channel Type for DBK43A
In DaqView

Selecting Channel Mode for DBK43A
In LogView

DBK43A Channel Types and Modes - Switch Positions
Channel Type
1(Mode)

1

CAL/NORM
SwitchFunction and Associated VOUT Equation

NORM

Sets the channel to read the value of the bridge circuit with all gains and offsets in effect. This is the normal
operation.

Offset(SetOffset)

NORM

Applies a grounded input to the channel. Sets the channel to read the circuit offset voltage multiplied by the
input amplifier and the low-pass filter gain.

Input Gain
(SetInputGain)

NORM

Applies 5 mV to the input channel. Sets the channel to read the voltage out of the circuit through the input
gain amplifier and the low-pass filter [if enabled].

Scaling Gain
(SetScalingGain)

NORM

Applies 5 mV to the input channel. Sets the channel to read the voltage out of the circuit through the input
gain amplifier, the low-pass filter [if enabled], and the scaling gain amplifier.

Excitation

CAL

BridgeVout = (Scaling Gain)(Filter Gain*)[(InputGain)(bridge circuit voltage) - offset voltage]

Vout = (Filter Gain*)(Input Gain) - offset voltage

Vout = (Filter Gain*)(Input Gain)(5 mV) - offset voltage

Vout = Filter Gain*(Scaling Gain[(Input Gain)(5 mV) - offset voltage])
Sets excitation.
Vout = (Excitation Voltage)

Shunt Cal

CAL

Activates shunt-cal resistors.
Vout = (Scaling Gain)(Filter Gain*)[(Input Gain)( bridge circuit voltage with shunt) - offset voltage]

DBK43A has one CAL/NORM switch. The “Up” position puts the switch in the “calibration” state. The “Down” position puts theswitch in the “Run” (Normal) state. DBK43B has two switches; for that module refer to the following table.
*In the equations, the asterisk indicates the conditional clause, “if the filter is enabled.”
1

DaqView uses the term “Channel Type.” LogView uses the term “Mode.” In the first column the “type” and “mode” names areoften the same for DaqView and LogView. When there are differences the LogView “Mode” name appears in parenthesis, forexample (SetInputGain) is LogView’s mode equivalent of DaqView’s “Input Gain.”

DBK43A & DBK43B, pg. 14

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DBK Option Cards and Modules

DBK43B Channel Types and Modes - Switch Positions
Channel Type
1(Mode)1

CAL1
SwitchCAL2
SwitchRUN(Down)

RUN(Down)

BridgeFunction and Associated VOUT Equation
Sets the channel to read the value of the bridge circuit with all gains and offsets ineffect. This is the normal operation.
Vout = (Scaling Gain)(Filter Gain*)[(InputGain)(bridge circuit voltage) - offset voltage]

Offset(SetOffset)

RUN(Down)

Input Gain
(SetInputGain)

RUN(Down)

Scaling Gain
(SetScalingGain)

Applies a grounded input to the channel. Sets the channel to read the circuit offset
voltage multiplied by the input amplifier and the low-pass filter gain.

CL2
(Up)

Vout = (Filter Gain*)(Input Gain) - offset voltage
Applies 5 mV to the input channel. Sets the channel to read the voltage out of thecircuit through the input gain amplifier and the low-pass filter [if enabled].

CAL2
(Up)

Vout = (Filter Gain*)(Input Gain)(5 mV) - offset voltage
RUN(Down)

Applies 5 mV to the input channel. Sets the channel to read the voltage out of thecircuit through the input gain amplifier, the low-pass filter [if enabled], and the scaling
gain amplifier.

CAL2
(Up)

Vout = Filter Gain*(Scaling Gain[(Input Gain)(5 mV) - offset voltage])
Excitation

Shunt Cal

CAL1
(Up)

CAL2
(Up)

CAL1
(Up)

CAL2
(Up)

Sets excitation.
Vout = (Excitation Voltage)
Activates shunt-cal resistors.
Vout = (Scaling Gain)(Filter Gain*)[(Input Gain)( bridge circuit voltage with shunt) offset voltage]

DBK43B has two switches: CAL1/RUN and CAL2/RUN. DBK43A only has one switch; for that module refer to the previous
table.
* In the equations, the asterisk indicates the conditional clause, “if the filter is enabled.”
1

DaqView uses the term “Channel Type.” LogView uses the term “Mode.” In the first column the “type” and “mode” names
are often the same for DaqView and LogView. When there are differences the LogView “Mode” name appears inparenthesis, for example (SetInputGain) is LogView’s mode equivalent of DaqView’s “Input Gain.”

DBK43B - Notes regarding CAL1 and CAL2
Mode

CAL1

CAL2

Comments

RUN &SET BRIDGE

RUN(Down)

RUN(Down)

Unlike the DBK43A, this run mode for the DBK43B allows for timestamping and event marking without signal error. Both switches“down” adds a grounded input to the channel and sets the channel
to read the circuit offset voltage multiplied by the input amplifier
and the low-pass filter gain.

CAL1
(Up)

RUN
(Down)SET INPUT GAIN,SET OFFSET, &SET SCALING GAIN

RUN
(Down)CAL2(Up)

SET EXCITATION &SET SHUNT CAL

CAL1
(Up)

CAL2
(Up)

DBK Option Cards and Module

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Not used. An invalid switch position.
Would simulate a DBK43A run mode. Used for setting input gain,
scaling gain, or offset.
With both switches up, the calibration mode is enabled. The
mode is identical to that of the DBK43A when its single
CAL/NORM switch is positioned to “CAL.”DBK43A & DBK43B, pg. 15

A Typical Setup Procedure, with Embedded Examples
Reference Notes:
Prior to using DBK43A or DBK43B with DaqView, you must select the module from
DaqView’s Configure Hardware Settings screen. If needed, refer to Chapter 3, DBK
Setup in DaqView.
Prior to using DBK43A or DBK43B with LogView, you must select the module from
LogView’s Hardware Configuration screen. If needed, refer to Chapter 4, DBK Setup in
LogView.
The board layouts in this DBK section can be referred to for jumper locations, jumper
setting orientations, and trimpot locations.
For Calibration – DaqView users should refer to the GageCal segment beginning on page
21 of this section. LogView users should refer to the section titled Calibrating DBK16,
DBK43A, and DBK43B for LogBook Applications, beginning on page 25.
1.

Verify that the low-pass filters are set to BYPASS. The filters are set via jumpers JPn04 where n is
the channel number (1 through 8); for example, JP104 sets the filter for channel 1, and JP804 sets thefilter for channel 8.
Note:

2.

If you plan to use filters during your acquisition, you should still select BYPASS at thispoint. Enabling the filters comes into play later in the procedure. However, if you do plan
to enable filters, note the gain in the filter stage (default ×2, or ×1 with resistor removed)
and allow for it in your setup.

Coupling is set via jumpers JPn03 where n is the channel number (1 through 8). Verify that the“Coupling” jumpers are installed. When installed, the channels are set for DC coupling.
Note:

If you plan to use AC Coupling during your acquisition, you should still select DC
Coupling at this point. Selecting AC Coupling comes into play later in the procedure.

3.

Determine the excitation for the transducer. This is based on the transducer specifications and fromthe current limitations of the DBK43 module’s excitation regulator.

4.

Determine the maximum voltage that can result from the transducer for a strain gage or for a loadcell. The values can be calculated as follows:
Strain Gage Example
Most strain gages come with Gage Factors (GF). To calculate the approximate output of the bridge
circuit with a typical strain value, use the formula:( Excitation Voltage)(Gage Factor)(Strain in strain units)= *Bridge circuit output voltage
4

In this strain gage example, lets assume the following:• We have a 120 ohm strain gage.
• The gage factor is 2.1.
• The excitation voltage is 5 V. This is due to the current limitation of the excitation regulator
on the DBK43 module [note that the excitation voltage must be less than 6 V]
• We are measuring 4000 micro-strain
By applying these values to the preceding equation we find that the bridge output voltage is 10.5 mV.
-6Bridge output voltage for 4000 microstrain =(5)(2.1)(4000 × 10 )4

= 10.5 mV*linear estimate (some strain gages are not linear); refer to strain-gage theory for more information.

DBK43A & DBK43B, pg. 16

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Load Cell Example

Load cells come with a mV/V specification; for each volt of excitation at maximum load, the loadcell will output a specific millivolt level. The following equation applies:
Load Cell Output Voltage = (LoadApplied/LoadRated)(Excitation Voltage)(Load Cell Rating)

For this example, lets assume the following:• We have a 350 ohm, 3000 pound load cell.
• The load cell is rated at 2.05 mV/V
• We are using an excitation of 10 V
By applying these values to the preceding equation we find that the Load Cell Output Voltage
is 20.5 mV.
Load Cell Output Voltage = (3000/3000)(10)(2.05×10-3) = 20.5 mVFor 1000 pounds applied load, the Load Cell Output Voltage would be one third of the 20.5 mVvalue, i.e., 20.5 mV/3 = 6.833 mV. If we used the entire equation we would see:
Load Cell Output Voltage = (1000/3000)(10)(2.05×10-3) = 6.833 mV

Now that we know our sensor’s full-scale voltage, we can calculate the DBK43 module’s voltage
gain. The proper voltage gain allows the full-scale sensor output to correspond to the full-scale inputof the data acquisition device. Full-scale device inputs are:-5 to +5 V for DaqBook and DaqBoard [ISA type] in bipolar mode
0 to +10 V for DaqBook, DaqBoard [ISA type], and DaqBoard/2000 Series
in unipolar mode
-10 to +10 V for DaqBoard/2000 Series in bipolar mode and for Daq PC-Card-10 to +10V for LogBooks in bipolar mode
0 to +20 V for LogBooks in unipolar mode5.

Calculate the channel total gain based on the full-scale LogBook or Daq device.
The following equation is used to calculate DBK43 total gain.
GainTOTAL = (Sensor Output VoltageFULL-SCALE – VoltageOFFSET) / Strain or Load VoltageOUTPUT

In this example we will use:
• a full-scale sensor output voltage of +5 V [for a DaqBook in bipolar mode].
• a 0.5 V offset (from full-scale) to prevent saturation• the 10.5 mV Bridge Output Voltage [for 4000 microstrain] from Example 1.
Using the gain equation we get:
GainTOTAL = (5.0 V – 0.5 V) / 10.5 mV = 4.5 V / 0.0105 V = 428.6
6.

Determine how the total gain will be distributed between the input amplifier gain, filter gain, andscaling amplifier gain.
An Example of Total Gain Distribution: If we round the gain of x428.6 [calculated in the previousstep] down to ×420, then the gain distributions indicated by the following table are possible.
Gain Distribution Options for a Total Gain of x420
Gain Stage &Associated Range

Possible Gain Distributions

Option A

Option B

Option C

Option D

×420

×100

×240

×300

Filter Gainx1 or x2

Disabled

×2

×1

Disabled

Scaling Gainx1 to x10

×1

×2.1

×1.75

×1.4

×420

×420

×420

×420

Input Gainx100 to x1250

Total Gain

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DBK43A & DBK43B, pg. 17

After we decide on a distribution option, the sensor can be hooked up to the DBK43 module, thebridge completion resistors can be installed, the excitation voltage set, followed by setting the gains.
In this example we will be using DaqView. Steps for other programs will be similar.
7.

Connect the transducer to the DBK43 module according to the figures in the Signal Connection(page 3) and Bridge Applications (page 5). Install the appropriate bridge-completion resistors if
applicable.

8.

Adjust the Excitation voltage.
Note: For DaqView versions 5.05 and higher the reading will already be correctly scaled.
(a) DBK43A users: Place CAL/NORM switch to “CAL.”DBK43B users: Place CAL1 and CAL2 “Up.”(b) DBK43A users:LogView users set the software CAL/NORM switch, in Hardware
Configuration, to “CAL.”DBK43B users: LogView users set the software switch parameter to 1’CAL+2’CAL.
(c) Select “Excitation” for the Channel Type.
(d) With the Reading column enabled, set the excitation voltage for the transducer by adjusting
the trimpot labeled EXC. Note that each of the eight channels has a channel-specifictrimpot for excitation.
(e) After the excitation voltage is set, stop the Readings.
(f) DBK43A users: Return the CAL/NORM switch to the NORM position.
DBK43B users: Return CAL1 to RUN “Down” and CAL2 “Up” (CAL).
(g) DBK43A users: LogView users set the software CAL/NORM switch to “NORM.”DBK43B users: LogView users set the software switch parameter to 1’RUN+2’CAL.
9. Adjust the Offset.
(a) DBK43A users: Place CAL/NORM switch in the NORM position.
DBK43B users: Place CAL1 “Down” (RUN) and CAL2 “Up (CAL.).
(b) DBK43A users: LogView users verify that the software CAL/NORM switch is selected to“NORM.”DBK43B users: LogView users verify the software switch parameter is set to
1’RUN+2’CAL.
(c) DaqView user’s: select “Offset” for the Channel Type.
LogView users: select “SetOffset” for the Mode.
(d) With the Reading column enabled, adjust the OFFSET trimpot (OFST) to obtain a channel
reading of 0.00 volts. This removes all offset from the DBK43 module’s channel circuit.
Note that each of the eight channels has a designated, channel-specific, trimpot for offset.
(e) After the Offset is adjusted to 0.00, stop the Readings.
10. Adjust the Input Gain.
(a) DBK43A users: CAL/NORM switch remains in the NORM position.
DBK43B users: Position CAL1 “Down” (Run) and position CAL2 “Up.”(b) DaqView users: select “Input Gain” for the Channel Type.
LogView users: select “SetInputGain” for the Mode.
(c) With the Reading column enabled, adjust the GAIN trimpot to obtain a voltage reading
equal to 0.005 x GI, where “GI” is the desired input amplifier gain. Note that each of theeight channels has a channel-specific trimpot for Input Gain.
(d) Stop the Readings.
For very high system gains you may need to first, set the Input Gain low, then set the Scaling
Gain, and then reset the Input Gain.

DBK43A & DBK43B, pg. 18

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DBK Option Cards and Modules

Typical input gain settings are shown in the following table.
Input Gains and Typical Readings
Input Gain

Readingx100

0.5 volts

x200

1.0 volts

x300

1.5 volts

x400

2.0 volts

x500

2.5 volts

x600

3.0 volts

x700

3.5 volts

x750

3.75 voltsx800

4.0 volts

x900

4.5 volts

x1000

5.0 volts

x1200

6 volts ** requires primary acquisition device to be in unipolar mode.
11. Adjust the Scaling Gain.
(a) DBK43A users: CAL/NORM switch remains in the NORM position.
DBK43B users: CAL1 remains “Down” (Run) and CAL2 remains “Up.”(b) DaqView users: select “Scaling Gain” for the Channel Type.
LogView users: select “SetScalingGain” for the Mode.
(c) With the Reading column enabled, adjust the SCALE trimpot (SCA) for a voltage reading
equal to .005 x GI x GS, where “GI” is the desired input amplifier gain and “GS” is thedesired scaling amplifier gain. Note that each of the eight channels has a channel-specific,
trimpot for Scaling Gain.
(d) Stop the Readings.
Scaling Gains Typical with an Input Gain of x200
Scaling Gain
x2
x4
x6
x8
x10

Reading
2.0 volts
4.0 volts
6.0 volts*
8.0 volts*
10.0 volts** requires primary acquisition device to be in unipolar mode.
12. Adjust the Offset while the bridge circuit is being read.
(a) DBK43A users: CAL/NORM switch remains in the NORM position.
DBK43B users: CAL1 remains “Down” (Run). Position CAL2 “Down” (Run).
(b) Select “Bridge.”(c) With the Reading column enabled, and with the quiescent (normal or inactive) load or strain
applied, adjust the OFFSET trimpot for a reading of 0.00 volts. This adds offset to thecircuit to compensate for the quiescent load and allows maximum resolution for themeasurement.
(d) After adjusting the Offset to 0.00, stop the Readings.
The Offset adjustment is unipolar 0 to 5 V on the input amplifier output. If the Offset can
not be adjusted to 0.00 V at the end of the setup procedure, swap the Vin+ (4) and Vin- (3)wire connections, or reduce the Input Gain and increase the Scaling Gain.
13. If required for your application, enable the low-pass filters. The filters are set via jumpers JPn04
where n is the channel number (1 through 8); for example, JP104 sets the filter for channel 1, andJP804 sets the filter for channel 8.
14. If required for your application, set AC Coupling. Coupling is set via jumpers JPn03 where n is thechannel number (1 through 8). To set AC Coupling, remove the JPn03 jumpers.
DBK Option Cards and Module

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DBK43A & DBK43B, pg. 19

15. Calculate the LogBook or Daq device voltage/transducer units. Do this using the transducer
specifications and the total gain of the DBK43 module’s channel. Apply the units to your readings.
16. Verify the software settings by using a known load or strain and comparing the value to thatobserved in DaqView’s Reading column.
Note:

Gain adjustments can be made by activating a shunt-cal resistor that is calculated to be at
maximum load.
To enable shunt-cal resistors:(a)Select “Shunt Cal” as the Channel Type.
(b)DBK43A users: Set CAL/NORM switch to CAL.
DBK43B users: Place CAL1 and CAL2 “Up.”(c)DBK43A users: LogView users: set the software CAL/NORM switch, in Hardware
Configuration, to “CAL.”DBK43B users: : LogView users verify the software switch parameter is set to
1’CAL+2’CAL.
Settings can be verified via shunt-calibration.
After the final offset is made, the gain readings will be incorrect unless the circuit
offset is removed.

DBK43A & DBK43B, pg. 20

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GageCal, Calibration Program for DBK16, DBK43A, and DBK43B in Daq Applications
GageCal is intended for DBK16, DBK43, DBK43A, and DBK43B load cell applications inconjunction with Daq devices.
GageCal is not used for LogBook applications.

GageCal is a calibration aid for use with DBK16, DBK43, DBK43A, and DBK43B devices that are being
used in Daq device data acquisition systems. The program, which is independent of DaqView, provides anon-screen walk-through for setting jumpers, switches and adjusting trimpots.
With GageCal you can:
• Use a graphic representation of a strain-gage board as a guide to configure switches, jumpers,
and other hardware settings.
• Enter all the parameters pertaining to your strain gage application.
• Follow step by step prompting to adjust trimpots for scale gain, input gain, and offset to ensure
the channel provides the desired input range.
GageCal is installed from the Master Setup screen of the data-acquisition CD-ROM as part of the
DaqBook/DaqBoard Support option. After your DaqBook/DaqBoard support has been installed you canaccess and use GageCal as follows.
1.

Access GageCal from a desktop shortcut, or by navigating from the desktop as follows:
Start ⇒ Programs ⇒ IOtech DaqXSoftware [or Omega DaqXSoftware] ⇒ GageCal
A Select Device window will appear, similar to that shown in the following figure.

GageCal – Select Device

2.

From the Select Device window, highlight the applicable DaqBook or DaqBoard, thin clickthe <OK> button. The Strain Gage Calibration window will appear.

GageCal’s Strain Gage Calibration Window

3.

DBK Option Cards and Module

Click the <AddCard> button. Then select one of the following, as applicable:
DBK16, DBK43, DBK43A, or DBK43B. See following figure.

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DBK43A & DBK43B, pg. 21

Selecting DBK43A

4.

Click the <OK> button. The Strain Gage Calibration window will provide 3 digit channel
numbers in the form of “n1-n2-n3;” where n1 is the card number, n2- is the bank number on thecard, and n3 is the channel number. See following figure.

Strain Gage Calibration Window after Adding a Card

5.

Click the <Calibrate> button. An Applications Parameter box appears. See following figure.

Application Parameters for Channel 0-0-0

DBK43A & DBK43B, pg. 22

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DBK Option Cards and Modules

6.

7.

Select the type of calibration to be performed, i.e., Nameplate, Two-Point, or Shunt. Then
edit the Application Parameters, if applicable. A brief description of the three calibration
methods follows. When done, click the <Continue> button.
•

Nameplate calibration provides a way to enter parameters for your strain gage
and its application. The final step of the procedure includes attaching the strain
gage (load cell).

•

Two-Point calibration provides a way to calibrate a DBK16, DBK43,
DBK43A, or DBK43B that is using a strain gage with unknown specifications.
In this method, the user enters two points of transducer output [milli-volts] vs.
engineering units, e.g., pounds. GageCal provides set up instructions based on
the parameters entered. The final step of the procedure includes attaching thestrain gage (load cell).

•Shunt calibration provides a means calibrating channels with use of usersupplied shunts to simulate a physical load. With this method, 1 or 2 shunt
resistors (Rn00D and Rn00H) are added for each of the 8 channels to becalibrated. You must set J3 to the position closest to TP9 for the shuntcalibration to work correctly. Shunt calibration is performed with the load-cellattached.

Follow GageCal’s screen prompts to complete the calibration.

Example Screen Shot from GageCal
Note: You can use GageCal’s “Diagnostics” feature to view a graphic representationof the strain gage and the card’s gain stages.

GageCal Diagnostics

8.

DBK Option Cards and Module

After completion, go to DaqView and convert ±5 V to engineering units using mx+b.

899892

DBK43A & DBK43B, pg. 23

DBK43A & DBK43B, pg. 24

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DBK Option Cards and Modules

Calibrating DBK16, DBK43A, or DBK43B for LogBook Applications
Overview …… 25
Calibration Methods …… 26
Procedures Common to All Calibration
Steps (Required) ……27
Nameplate Calibration and
Manual Calibration ……30

Channel Calibration Procedure ……33
2-Point Calibration ……36
Shunt Calibration ……38
Creating a Units Conversion Transfer Function ……40
Periodic Calibration Without Trimpots ……41

Overview
Calibrating a strain gage channel includes:
One-time adjusting of the bridge excitation.
One-time tuning of the electronic gains and offset via trimpots to maximize performance anddynamic range.
Applying a transfer function to the voltage output to convert it to engineering units, e.g., pounds,
kilograms.
Executing a software scale and offset adjustment periodically to maintain accuracy.

Example of a Unit Conversion from Voltage to Pounds

The trimpots provide course tuning so large quiescent offsets can be nulled and the bridge signal can beamplified to match the A/D input range. Once these adjustments are made, the operator can periodicallyfine-tune the calibration via software using LogView’s 2-Point calibration feature. LogView’s scale andoffset features provide a simple means to apply a transfer function that converts the voltage to user units,
for example, pounds, as in the above block diagram.
Bridge circuit transducers are used for many different applications, and the strain gage signal conditioning
modules are flexible enough to support most of them. Each channel circuit has an excitation regulator, ahigh gain (x100 to x1250) input amplifier with offset adjustment, a low-pass filter, a scaling (x1 to x10)
amplifier, and a calibration multiplexer.
By using software-controlled multiplexers, on-board reference voltages can be read by the data acquisition
system so that precise gains and offsets can be set. LogView provides a means of easily controlling thecalibration multiplexers so that the reference voltages can be displayed while the trimpots are being
adjusted.

DBK Option Cards and Module

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DBK43A & DBK43B, pg. 25

There are four trimpots to set up each channel circuit. The trimpots are labeled to represent the following
adjustments:•

EXC - for adjusting the excitation voltage to the transducer•

GAIN - for setting the gain of the input amplifier•

OFFSET - for adjusting the circuit offset for quiescent loads or bridge imbalance•

SCALE - for setting the gain of the scaling amplifier

Signal-FlowRelationship of Software Controlled Multiplexers and On-Board Reference Voltages

This calibration procedure can only be executed while LogBook is attached to a PC thatis running LogView.
To adjust trimpots, use one of the following calibration methods, as appropriate.

Calibration Methods
Several different calibration techniques are supported by strain gage signal conditioning modules.
Calibration methods include; Nameplate, 2-Point, Shunt, and Manual. From the following discussion,
select the calibration method that is best for your application.

Nameplate – Used to setup the channel using the transducer’s published specs.
Nameplate calibration is typically used with packaged load cells with millivolt-per-volt (mV/V) transfer
functions. Using the mV/V spec of the load cell or a strain gage’s Gage Factor (GF), the necessary system
gain can be calculated and applied to a channel.

2-Point – Used to setup the channel using 2 known loads, one of which might be “no load.”
The 2-Point calibration method requires the operator to apply two known loads to the load cell or strain
gage, one at a time, while the data acquisition system takes measurements. Typically, the first point is withno load applied and the second point is close to the maximum load capacity of the gage. While measuring
the first point the offset is nulled, and while measuring the second point the gain is adjusted to span the
majority of the input range of the A/D. No gain calculations are required to perform this calibration
method.

DBK43A & DBK43B, pg. 26

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DBK Option Cards and Modules

Shunt – Used to setup the channel using a shunt resistor applied to the bridge to simulate a load.
Shunt calibration is identical to 2-Point calibration except that the second point is simulated so that
applying a load near the gage’s maximum load is unnecessary. To simulate a bridge imbalance, a shunt
resistor is placed across one leg of the bridge. Once the shunt resistor value has been calculated, it isapplied to the bridge to provide the desired simulated load. No gain calculations are required to perform
this calibration method.

Manual – Used to assign specific gains and offsets.
If a particular gain and offset are already known, these values can be used to setup a strain gage channel.

Procedures Common to All Calibration Steps (Required)
Set the Selected Channel(s) to DC Coupling
Since the applied calibration-signals are DC, set DC coupling for all the channels that are being adjusted.
If your application requires AC coupling, don’t forget to remove the jumpers when the adjustment
procedure has been completed.

Determine Channel Parameters
Before adjusting the trimpots, the excitation needs to be determined. Typically, the supplier of the gage ofload cell will recommend a suitable value, but make sure that the maximum output current of the excitation
regulator is not exceeded.

Initialize LogView
Launch LogView and use the LogBook Hardware Configuration window (hardware tree) to configure allof the DBK options that are to be used in the system. If needed, refer to the LogView chapter of the
LogBook User’s Manual (p/n 461-0901).

LogBook Hardware Configuration, Button and Screen

Open the Analog Input Channel Configuration Window. Click the User Scaling Tab and verify that all of
the strain gage channels that are to be adjusted have scale and offset values of 1 and 0, respectively.

Analog Input Channel Configuration Window, Button and Screen … “User Scaling” Tab Selected

DBK Option Cards and Module

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DBK43A & DBK43B, pg. 27

For all of the strain gage channels that are to be adjusted, set their ranges to +5V.
Click the DBK Parameters tab to expose the strain gage signal conditioning programmable settings.
Click the Attach button to substantiate a connection between the PC and the LogBook.

Adjust the Excitation - DBK16

For DBK16, set the excitation voltage for the transducer by adjusting the trimpot labeled EXC andmeasuring the voltage with a voltmeter across the +EXC and -EXC on the bridge or at the terminals of thesignal conditioning module.
Adjust the Excitation-

DBK43A - DBK43B

DBK43A and DBK43B are equipped with a switch that allows the excitation voltage to be read by the
LogBook and displayed in LogView. For a DBK43A orDBK43B to be adjusted, you must:
1.

DBK43A users: Reposition the DBK43A’s “physical” calibration switch to the CAL position.
DBK43B users: Position DBK43B’s CAL1 and CAL2 to the calibration position.

2.

Select CAL in LogView. Open the LogBook Hardware Configuration window and select theappropriate DBK43A (see following figure).
DBK43A users: In the Configurations settings box, set the CAL/NORM Switch to CAL. If the
DBK43A is not displayed click the + to the left of the base channel (to which it is attached), this action
expands the hardware tree in the LogBook Hardware Configuration window. Repeat this process for
all DBK43A units that are to be adjusted. Click OK to lock in the changes.
DBK43B users: In the Configurations settings box set the software switch parameter to

1’CAL+2’CAL.
Setting a DBK43A Cal/Norm Switch to “CAL”

3.

In the Param1 column (see next figure for location), select all of the DBK43 channels that are to be
adjusted.

4.

Set Mode equal to Excitation from the drop down list (located above the DBK Parameters tab).

5.

Turn off all the channels in the system except for those DBK43A channels that are to be adjusted.

DBK43A & DBK43B, pg. 28

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DBK Option Cards and Modules

Selecting “Mode = Excitation” for DBK Parameter 1
Note: The Param2 column will show two switch positions for DBK43B applications.

6.

Click the Download button to send the current configuration to the LogBook.

7.

Select Indicators \ Enable Input Reading Column from the menu bar to display the
excitation values for each channel.

Selecting “Enable Input Reading Column”(from the Indicators Pull-Down Menu)

8.

Set the excitation voltage for each transducer by adjusting the trimpot labeled EXC for the
associated channel while reading their values in LogView.

9.

Select Indicators \ Disable Input Reading Column from the menu bar.

Selecting “Disable Input Reading Column”(from the Indicators Pull-Down Menu)

10. DBK43A users: Return the physical calibration switches (of the applicable DBK43As) to the
NORM position.
DBK43B users: Return CAL1 to RUN (Down); and CAL2 to CAL (Up).

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DBK43A & DBK43B, pg. 29

11. DBK43A users: In LogView, open the LogBook Hardware Configuration Window (hardwaretree) and select NORM for each DBK43A.
DBK43B users: In LogView, open the LogBook Hardware Configuration Window (hardwaretree) and select RUN for the CAL1 switch and select CAL for CAL2.

This completes the section entitled: “Procedures Common to All Calibration Steps (Required)”Nameplate Calibration and Manual Calibration
To properly calibrate a strain gage channel using the Nameplate method, the required gain must first be
calculated. If the desired gain and offset are already know [as in the Manual calibration method] skip to
the section, Determining the Gain of Each Amplification Stage.
The following examples outline the necessary steps for determining the required gain for
Nameplate calibration. Both strain gage and load cell examples are provided.

Calculating the Required Gain
Determining a Strain Gage’s Maximum Output Voltage
Most strain gages come with Gage Factors (GF) used to calculate the approximate output of the bridge
circuit with a typical strain value. The formula is:
VBR = (VEXC * G * S * B) / 4[See following important notice.]

Where: VBR = Bridge output voltage
VEXC = Excitation Voltage
G = Gage Factor
S = Strain in user units (in uStrain)
B = Configuration factor (1 for ¼ bridge, 2 for ½ bridge, 4 for full bridge)
The equation, VBR = (VEXC * G * S * B) / 4 produces a linear estimate. If you areusing a non-linear strain gage you should refer to strain gage theory for additional
information as needed.

For a 120 ohm strain gage with a gage factor of 2.1 and excitation voltage of 5 V, applying
4000 microstrain would produce an bridge output of 10.5mV for a ¼ bridge configuration.
VBR = (5 * 2.1 * 4000x10-6) / 4 = 10.5 mV
Determining a Load Cell’s Maximum Output Voltage
Load cells come with a mV/V specification—for each volt of excitation at maximum load, the load cell
will output a specific millivolt level.
VLC = R * VEXC

Where: VLC = Load cell output voltage
R = Load cell spec (mv/V)
VEXC = Excitation voltage

Consider a 3000 pound load cell rated at 2.05 mV/V using 10 V of excitation (assume a 350Ω load cell).
When 3000 pounds is applied, the voltage out of the load cell is 20.5mV.
DBK43A & DBK43B, pg. 30

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VLC = (10 * 2.05×10-3) = 20.5 mV

If 1000 pounds were applied, we would see 6.833 mV. This is arrived at as follows:(1000/3000) * 10 * 2.05×10-3 = 6.833 mV
Using the Calculated Maximum Voltage to Determine the Necessary Gain
To maximize the resolution and dynamic performance of the system, the sensor’s output should be
amplified to correspond to the data acquisition system’s input range.

Using the LogBook’s +5V input range, the required gain is calculated by dividing 5V by the maximum
output voltage of the sensor. Before performing the calculation, it is typically a good idea to pad the
maximum sensor voltage by about 5% so that, once amplified, it won’t bump into the limit of the 5V range.
G = VLB / (VGO + VGO * 5%)

Where: G = Gain
VLB = LogBook input range
VGO = Maximum gage output

For the strain gage in the previous example with a maximum output of 10.5mV, the required gain is:
G = 5.0V / (0.0105V + 0.0105V * 0.05) = 453.5
For the above load cell with a maximum output of 20.5mV, the required gain is:
G = 5.0V / (0.0205V + 0.0205V * 0.05) = 232.3

Determining the Gain of Each Amplification Stage

The system’s total gain is:
GT = GI * GF * GS

Where: GT = Total gain
GI = Input amplifier gain
GF = Filter gain
GS = Scaling amplifier gain
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DBK43A & DBK43B, pg. 31

Note: Maximum gain calibration is x1000 for +5V range.

The majority of the gain should be assigned to the Input Amplifier, with the Scaling Amplifier used forfine-tuning. If the filter is enabled, a gain of x2 is automatically introduced.
The input amplifier has a gain range of ×100 to ×1250; the filter gain ×1 or ×2; and the scaling amplifier
has a range of ×1 to ×10. For the strain gage example, if we round off our gain to ×420, any of these
possible settings will work.

Option A

Option B

Option C

Option D

Input Gain

×420

×100

×240

×300

Filter Gain (enabled)No

Yes (×2)

Yes (×2) *See Note

No

Scaling Gain

×1

×2.1

×1.75

×1.4

Total Gain

×420

×420

×420

×420

For Option C, the LPF gain is typically x2.
For gains of x1 (if the filter is enabled), the following apply:

DBK16 - For a gain of x1 (if the filter is enabled),10KΩ resistors R44 and R46 must have beenpreviously removed (for the low and high channels, respectively).
DBK43A and DBK43B - For a gain of x1 (if the channel filters are enabled), removal of thefollowing 10 KΩ resistors applies: Ch0 – R144, Ch1 – R244, Ch3 – R444, Ch4 – R544,
Ch5 – R644, Ch6 – R744, Ch7 – R844.

DBK43A & DBK43B, pg. 32

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Channel Calibration Procedure
Adjust the Offset
The following steps are used to adjust the offset.
1.

In the Param1 column (see page 29 for location), select all of the DBK43A channels that are
to be adjusted.

2.

Select Mode = SetOffset from the drop down list above the grid. This selection commands
the calibration multiplexer to route the 0.0V reference through the entire analog path (seefollowing figure).

“Mode = Offset” 0.0 Volt Reference is Routed

3.

Turn off all the channels in the system except for those DBK43A channels that are to be
adjusted.

4.

Click the Download button. This sends the current configuration to the LogBook.

5.

Select Indicators \ Enable Input Reading Column from the menu bar. This displays the offset
values for the enabled channels.

6.

Set the offset voltage to 0.0V for each transducer by adjusting the trimpot labeled OFFSET
for the associated channel.

7.

Select Indicators \ Disable Input Reading Column from the menu bar.

Adjust the Input Amplifier Gain
Perform the following steps to adjust the Input Amplifier Gain.
1.

In the Param1 column (see page 27 for location), select all of the DBK43A channels that are
to be adjusted.

2.

Select Mode = SetInputGain from the drop down list above the grid. This selectioncommands the calibration multiplexer to route a 5mV reference through the Input Amplifierand bypass the Scaling amplifier (see following figure).
Note: If the filter is enabled (not bypassed) accommodate an additional x2 gain stage.

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DBK43A & DBK43B, pg. 33

“Mode = SetInputGain,” 5 milli-Volt Reference Route3.

Turn off all the channels in the system except for those DBK43A channels that are to be
adjusted.

4.

Click the Download button to send the current configuration to the LogBook.

5.

Select Indicators \ Enable Input Reading Column from the menu bar to display the values foreach channel.

6.

For the associated channel, set the voltage to [GI * GF * 0.005] for each transducer by
adjusting the trimpot labeled GAIN. Use the Input Amplifier Gain (GI ) calculated earlier.
Note: If the filter is enabled, the filter gain (GF ) is 2; otherwise GF = 1.
Example 1: If GI = 250 and the filter is disabled; the GAIN
trimpot would be adjusted to obtain 1.25V.
Example 2: If GI = 250 and the filter is enable; the GAIN
trimpot would be adjusted to obtain 2.50V.

7.

Select Indicators \ Disable Input Reading Column from the menu bar.

Adjust the Scaling Amplifier Gain
Adjust the Scaling Amplifier Gain as follows:1.

In the Param1 column (see page 27 for location), select all of the DBK43A channels that are
to be adjusted.

2.

Select Mode = SetScalingGain from the drop down list above the grid. This selectioncommands the calibration multiplexer to route a 5mV reference through all of theamplification stages as shown below.

“Mode = ScalingGain,” 5 milli-Volt Reference Route
DBK43A & DBK43B, pg. 34

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3.

Turn off all the channels in the system except for those DBK43A channels that are to be
adjusted.

4.

Click the Download button to send the current configuration to the LogBook.

5.

Select Indicators \ Enable Input Reading Column from the menu bar to display the values foreach channel.

6.

For the associated channel, set the voltage to [GT * 0.005] for each transducer by adjusting
the trimpot labeled SCALE. Use the total system gain (GT ) calculated earlier.
Example: If GT = 435.5, the SCALE trimpot would be adjusted to obtain 2.17 V.

7.

Select Indicators \ Disable Input Reading Column from the menu bar.

Trimming Bridge Quiescent Load
Most bridges have some level of offset, even if no quiescent load is present. In quarter and half bridge
situations, use of 1% bridge completion resistors can cause up to 1mV/V of offset. If the bridge has 4mVof offset and the Input Amplifier is set to x100, the Offset potentiometer would need to nullify 400mV.
DBK16 – For DBK16s, the Offset Potentiometer can adjust out 0 to +5V of offset amplified by the
Input Amplifier.
DBK43A and DBK43B – For these two modules, the Offset Potentiometer can adjust out -1.25 to +5V ofoffset amplified by the Input Amplifier.

Trimming Bridge Quiescent Load

If a significant amount of quiescent offset is present and the Input Amplifier gain is set too high, theOffset Potentiometer will not have enough range to adequately nullify the offset. In this case, the gain of
the Input Amplifier must be reduced while the gain of the Scaling Amplifier is increased proportionately.
Use the following steps to trim bridge quiescent load (unload the bridge).
1.

DBK43A users: Place the unit’s physical switch to NORM position.
DBK43B users: Place the physical CAL1 and CAL2 switches to the RUN position.

2.

In the Param1 column (see page 27 for location), select all of the DBK43A [or DBK43B]
channels that are to be adjusted.

3.

Select Mode = Bridge from the drop down list above the grid. This selection commands thecalibration multiplexer to route the transducer output through the analog path as shown
below.

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DBK43A & DBK43B, pg. 35

“Mode = Bridge,” Reference Route3.

Turn off all the channels in the system except for those DBK43A [or DBK43B] channels thatare to be adjusted.

4.

Click the Download button to send the current configuration to the LogBook.

5.

Select Indicators \ Enable Input Reading Column from the menu bar to display the offset
values for each channel.

6.

For the associated channel, set the offset voltage to 0.0V for each transducer by adjusting thetrimpot labeled OFFSET.
Note: If you are unable to nullify the quiescent offset of the bridge, your Input Amplifier
gain may be too high. Information regarding gain redistribution can be found in thesection entitled, Determining the Gain of Each Amplification Stage.

7.

Select Indicators \ Disable Input Reading Column from the menu bar.

2-Point Calibration
This 2-point calibration method makes use of trimpot adjustments. It should not be
confused with the LogView software 2-Point Calibration (discussed in the LogView
chapter in the LogBook User’s Manual).

In the 2-Point calibration method, the user places two known loads on the gage, one at a time, then adjust
the trimpots until the expected value is reached. Typically, the first of loads is “no load.” In the case of aweight scale, the scale would first be unloaded to adjust the offset, then a known load (near maximum
expected) would be applied to adjust the gain.
Shunt calibration (discussed immediately after this 2-Point Calibration section) is the same as the 2-Point
method, except the second load is applied in a simulated fashion by shunting 1 leg of the bridge with ashunt resistor. Shunt calibration is preferred in cases where applying a real load (near the maximum
expected) is not practical.

Initialize the System

DBK43A & DBK43B, pg. 36

1.

DBK43A users: Verify that the unit’s physical switch is in the NORM position.
DBK43B users: Verify that the unit’s physical CAL1 and CAL2 switches are both in the
RUN position.

2.

Download a single setup and continuously display data in LogView. The continuous display
can remain throughout the procedure since the calibration multiplexers do not need reset
between steps.

3.

In the Param1 column (see page 29 for location), select all of the DBK43A [or DBK43B]
channels that are to be adjusted.
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4.

Select Mode = Bridge from the drop down list above the grid. This selection commands thecalibration multiplexer to route the transducer voltage through the analog path.

5.

Turn off all the channels in the system, except for those DBK43A [or DBK43B] channels thatare to be adjusted.

6.

Click the Download button to send the current configuration to the LogBook.

7.

Select Indicators \ Enable Input Reading Column from the menu bar to display the offset
values for each channel.

Adjust the Offset
For the associated channel, apply the first calibrated load to each gage (typically no-load) and set thevoltage to 0.0V for each transducer. This is accomplished by adjusting the trimpot labeled OFFSET. If thefirst point is actually a calibrated load, you will need to move the load to each gage, one at a time, to adjust
its associated offset.

Adjust the Input and Scale Amplifier Gain
Complete the following steps to adjust the channel gain.
1.

Apply the second load to each gage channel. The value of this load should approximate thatof the maximum expected load. For the best results, a gain should be selected so that thebridge’s maximum output equals 90% of the A/D’s input range.

2.

Calculate the desired voltage for the second point using the following equation:
VD = (LA/LM) * VI * 90%

Where: VD = Desired voltage for 2nd point of calibration
LA = Applied load used in calibrating the 2nd point
LM = Maximum load expected during usage
VI = Input voltage range
Example: The load standard that will be applied to the gage as the 2nd point in the 2-Point
calibration is 100lbs. The maximum expected load during usage is 150lbs.
The programmable input range of the data acquisition system is set for +5V.
The desired output voltage of the strain gage signal conditioning electronics is:
VD = (100/150) * 5 * 0.90 = 3V

In this example, we should adjust the GAIN and SCALE trimpots until a value of 3V ismeasured.
If 150 lbs is applied to the gage, a voltage of 4.5V will be measured.
VD = (150/150) * 5 * 0.90 = 4.5V

3.

Apply the second calibrated load to each gage and set the voltage to VD, as derived in step 2.
Do this for each transducer by adjusting the trimpots labeled GAIN and SCALE for the
associated channel. Note that the GAIN trimpot provides most of the amplification (course
adjustment), while the SCALE trimpot allows for fine-tuning.

Repeating the Process
Since adjusting the gain for the first time will have an affect on the offset, it is recommended that offset and gain adjustment be performed twice for each channel.

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DBK43A & DBK43B, pg. 37

Shunt Calibration
Shunt calibration is virtually identical to the 2-Point method just discussed, except that the second point issimulated. The simulated load is achieved by shunting one leg of the bridge with a shunt resistor. Shuntcalibration is the preferred calibration method when applying a real load (of a value approximating the
maximum expected load) is not practical. To adjust the channel gain, the shunt must be applied to thebridge.
Calculate and install the necessary shunt resistor before continuing.
DBK43A has direct support for shunt calibration, accommodating theresistor in its enclosure and allowing the software to apply it when requested.
DBK16 does not have direct support, so the shunt resistor must be appliedexternally and switched in manually.

Adjust the Offset
1.

DBK43A users: Verify that the unit’s physical switch is in the NORM position.
DBK43B users: Verify that the unit’s physical CAL1 and CAL2 switches are both in the
RUN position.

2.

In the Param1 column, select all of the DBK43A [or DBK43B] channels that are to be
adjusted.

3.

Select Mode = Bridge from the drop down list above the grid. This selection commands thecalibration multiplexer to route the transducer voltage through the analog path.

4.

Turn off all the channels in the system except for those DBK43A [or DBK43B] channels thatare to be adjusted.

5.

Click the Download button to send the current configuration to the LogBook.

6.

Select Indicators \ Enable Input Reading Column from the menu bar to display the offset
values for each channel.

7.

For the associated channel, apply the first calibrated load to each gage (typically no-load) andset the voltage to 0.0V for each transducer by adjusting the trimpot labeled OFFSET.

If the first point is an actual calibrated load, you must move the load to each gage, one at atime, to adjust its associated offset.

Adjust the Input and Scale Amplifier Gain
For the best results, a gain should be selected so that the bridge’s maximum output equals 90% of the
A/D’s input range.
1. Use the following equation to calculate the desired shunt voltage (VD).
VD = (Ls/LM) * VI * 90%

Where: VD = Desired voltage from the after amplification when the shunt is applied
Ls = Simulated load produced by shunt
LM = Maximum load expected during usage
VI = Input voltage range
Example: The simulated load produced by the shunt 100lbs. The maximum expected load during
usage is 150 lbs. The programmable input range of the data acquisition system is set
for +5V. The desired output voltage of the strain gage signal conditioning electronics
is: VD = (100/150) * 5 * 0.90 = 3V

In this example, we would adjust the GAIN and SCALE trimpots until a value of 3V
is measured. If 150lbs is applied to the gage, a voltage of 4.5V will be measured.
VD = (150/150) * 5 * 0.90 = 4.5V
DBK43A & DBK43B, pg. 38

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DBK Option Cards and Modules

For DBK16, only … Externally apply the shunt resistor and set the voltage to VD, as derived above for eachtransducer. This is done by adjusting the trimpots labeled GAIN and SCALE for the associated channel.
The GAIN trimpot is used for course adjustment; and the SCALE trimpot for fine-tuning.
For DBK43A only … For each DBK43A to be adjusted, move the physical switch from NORM to CAL.
For DBK43B only … For each DBK43B to be adjusted, move the two physical switches from RUN to
CAL1 and CAL2 respectively.
2.

In LogView, open the LogBook Hardware Configuration window and select the DBK43A.

LogBook Hardware Configuration, Button and Screen

3.

Select the DBK43A [or DBK43B] from the LogBook Hardware Configuration window’s hardware
tree.

4.

Set the list box to the right to CAL. If the DBK43A [or DBK43B] is not displayed click the + to theleft of the base channel to which it is attached to expand the hardware tree.

Setting a DBK43A Cal/Norm Switch to “CAL”

5.

Repeat this process for each DBK43A [or DBK43B] that is to be adjusted.

6.

Click OK to lock in the changes.

7.

Open the Analog Input Channel Grid. In the Param1 column (see page 27 for location), select all of
the DBK43A [or DBK43B] channels that are to be adjusted. Select Mode = Shunt from the drop
down list above the grid. Turn off all the channels in the system except for those DBK43A [orDBK43B] channels that are to be adjusted.

8.

Click the Download button to send the current configuration to the LogBook.

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DBK43A & DBK43B, pg. 39

9.

Select Indicators \ Enable Input Reading Column from the menu bar to display the excitation
values for each channel.

10. Set the voltage to VD, as derived above, for each transducer. This is accomplished byadjusting the trimpots labeled GAIN and SCALE for the associated channel. The GAIN
trimpot provides for course adjustment. The SCALE trimpot provides for fine tuning.
11. Select Indicators \ Disable Input Reading Column from the menu bar.
12. DBK43A users: Return the physical NORM/CAL switches to the NORM position.
DBK43B users: Return CAL1 and CAL2 to the RUN position.
13. DBK43A users: In LogView, open the LogBook Hardware Configuration window and returneach DBK43A to NORM.
DBK43B users: In LogView, open the LogBook Hardware Configuration window and returneach DBK43B to a software switch parameter status of: 1’RUN+2’RUN.
14. Change the mode to Bridge.

Repeating the Process
Since adjusting the gain for the first time will have an affect on the offset, it is recommended that
offset and gain adjustment be performed twice for each channel.

Creating a Units Conversion Transfer Function
To make the data from your gage more useful, it should be recorded in terms of units appropriate to yourapplication, such as pounds, kilograms, inches, mm, or Hg. A transfer function is needed to convert volts tothese more meaningful units.
For this purpose, LogView provides a means of assigning a mathematical scale and offset to each channel.
Scale and offset information from that chapter has been repeated below for convenience.

In User Scaling, you can create a transfer function. The function allows LogView to display units that could
be more useful to you than volts. For example, you could obtain readings with pounds as the designated Units.
The reading (in pounds) will be based on the raw input value, typically Volts, and the indicated Scale and Offset
adjustment.
To create the transfer function:
1.

Type the desired unit name in the Units column.

2.

Select an appropriate range (e.g. unipolar).

3.

Enter the linear scale relation to Volts (e.g. 25 pounds per Volt).

4.

Enter any offset from 0, for example, an empty basket used in an
application reads 0.1 V.

The reading and range columns will automatically change to the adjusted values.

DBK43A & DBK43B, pg. 40

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Periodic Calibration Without Trimpots
Once the trimpots have been adjusted during initial installation, periodic trimming can be performed
through LogView’s 2-Point software calibration. The LogView procedure does not require the use oftrimmpots and should not be confused with the 2-point method discussed in this section of the manual.
Refer to the LogView chapter in the LogBook User’s Manual for information regarding 2-point calibration
via software.

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DBK43A & DBK43B, pg. 41

Specifications - DBK43A and DBK43B Strain Gage Modules
The following specifications apply to both strain gage modules, with exception to the connectors, as noted.
Name/Function: Strain-Gage Module
Connectors:
DBK43A: P1 DB37; mini-DIN6 for strain-gage or external excitation connections
DBK43B: P1 DB37; removable screw terminal blocks for strain-gage or external excitation connections
Number of Channels: 8
Excitation Voltage Adjustment Ranges: 1.50 to 10.50 VDC @ 50 mA
Input Gain Range: ×100-1250; separate instrumentation amplifier for each channel with gain adjustable via
externally accessible 15-turn trimpot
Accommodated Bridge Types:
Full bridge, Kelvin excitation (6-wire)
Full bridge (4-wire)
Half bridge (3-wire)
Quarter bridge (3-wire)
Bridge-Completion Resistors: On-board resistor socket locations (Rn00A, Rn00B, Rn00C, Rn00E, Rn00F,
and Rn00G) for 6 bridge-completion resistors per channel
Input Type: Differential
Input Impedance: 100 MΩ || 100 pF
CMMR: 115 dB (DC to 60Hz)
Excitation Current Output: 50 mA max (current limited @ 60 mA)
Excitation Sensing: Local or remote
Excitation Regulation
Line Regulation: 0.01% typical 0.1% max
Load Regulation: 0.03% typical 0.2% max
Gain Calibration Reference: 5 mVDC
Gain Calibration Reference Accuracy: 0.2%
Gain Calibration Reference Drift: 20 ppm/°C
Gain Accuracy: 0.5%
Gain Drift: 50 ppm/°C
Input Offset: 40 µV typical 200 µV max (offset adjustable to zero)
1

Input Offset Drift: 1 µV/ºC typical 4 µV/°C max

Output Offset: 2mV typical 8mV max (offset adjustable to zero)1

Output Offset Drift: 100 µV/°C 200 µV/°C max

Offset Adjustment: 0-100% of range, 0-5 VDC (15-turn trimpot)
Full-Scale Sensitivity Range
5.00 VDC Excitation: 0.8-10 mV/V
10.00 VDC Excitation: 0.4-5 mV/V
Scaling Amplifier Gain Range: ×1-10 (15-turn trimpot)
Low-Pass Filter:
3-pole, user-selected
Corner frequency (Fc) set by user component
Attenuation -3 dB at Fc
Gain ×2
Power: 9 to 18 VDC, external supply provided, 16 Watts maximum

Note 1: Total drift (referred to input) is: Input Offset Drift +DBK43A & DBK43B, pg. 42

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Output Offset Drift
Input Gain (as set by trimpot )DBK Option Cards and Modules