DAC488HR/4

16‑bit D/A Converter with Digital I/O & IEEE 488Features• Four isolated 16‑bit outputs• 100 kHz/channel update rate
• 480 Ksamples/channel max buffer• ±1, ±2, ±5, and ±10 VFS programmableunipolar and bipolar output ranges• One‑shot, step, burst, waveform, andcontinuous output modes• GET, external TTL, IEEE command,and time event trigger sources• ASCII, binary, integer decimal, and  
hexadecimal data formats• Standard sine, square, and triangle
waveform generation• 500 VDC channel-to-channel ­isolation• Eight digital inputs and eight digital
outputs• 100 mA high-current outputs
The DAC488HR/4 is an IEEE 488 programmable 16‑bit D/A converter. It is configured
with four output channels which are optically isolated from each other and fromIEEE 488 common by up to 500 VDC. Eachchannel is independently programmablefor 1, 2, 5, or 10 VFS unipolar or bipolar
output, specified as either bits or volts inASCII, integer, hexadecimal, or binary
format. Multiple output modes, multiple
clock and trigger sources, and buffer
management enable the DAC488HR/4
to function as a precision voltage source,a function generator, or an arbitrary­waveform generator.
Waveforms captured by IOtech’s 16‑bit,
100 kHz ADC488/A Series digitizers can beedited and transferred to the DAC488HR/4
for output. The ADC488/A Series and DAC488HR/4 in combination form a powerful
waveform I/O system. Typical applications
include transducer simulation, disk-drive
testing, vibration analysis, and materials
testing.

Measurement Computing

The versatile DAC488HR/4 functions as a voltage source, function generator, and an arbitrary
waveform generator

Up to 13 IEEE 488 devices
SCSI488/S

DAC488HR/2

Filter488

DAC488HR/4

IEEE

DAC488HR/4IEEE 488
controller+- +- +- +CH1 CH2 CH3 CH44-channel 16-bit,
isolated 100-kHz
analog outputs

Trigger Modes
The DAC488HR/4’s five trigger modes­support a wide variety of applications.
Bus Control Mode. Each port is programmed to output a specified value under
direct control from the IEEE 488 bus. Thismode is useful for maintaining an initialvalue until a specified condition occurs.
Step Mode. When a specified trigger isdetected, a value is output from the ­buffer,and the DAC488HR/4 is automatically­
re-armed until the specified buffer countis reached. The last ­specified buffer value
is held as the output.

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8 digital 8 digital
outputs inputs

Burst Mode. Functionally identical to step
mode, except that waveforms rather thansingle values are output.
Waveform Mode. Based on recognition ofa trigger, the waveform buffer is output fora specified number of cycles.
Continuous Mode. Data is continuously input
from the IEEE 488 bus and output to an analog channel at rates up to 200 Kbytes/s upon
the detection of a specified trigger. Thismode is ideally suited for audio, speech,
and other applications that require long
duration waveforms.

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DAC488HR/4
General Information
DAC488HR/4 Design
Four independent analog output modules are optically isolated
from the IEEE 488 bus, digital circuitry, earth ground, and chassis
common by up to 500 VDC. Each module consists of a microcontroller and expandable data buffer. A common update clock
is shared by all ports, ensuring synchronization. Four internal
clock sources are available to meet a wide variety of applications
including CD and DAT testing. An external clock source (up to10 MHz) allows synchronization to an external frequency reference and can be used to synchronize the DAC488HR/4 to theADC488/A Series ­digitizers for stimulus/response applications.

Isolated

Powersource 1
Isolated
analogoutputD/Achannel 2

All DAC488HR/4 ports share a common trigger source, ensuring multi‑channel synchronization for applications withcritical time and phase relationships. Trigger sources for theDAC488HR/4 include trigger command, IEEE 488 Group Execute Trigger (GET), and external TTL (rising or falling edge)
signal input. Triggers can also be initiated on periodic intervals
from 2 ms to 65,535 ms, specified in 1 ms increments. The
DAC488HR/4 provides a delayed TTL-level trigger output for
stimulus/response applications in which the device under test
(DUT) must attain a steady state prior to measurement. Thisfunction allows users to specify a time delay, in update clock
counts from 1 to 65,535, between the DAC488HR/4’s output
and the trigger signal’s output.

Powersource 3
D/Achannel 3Powersource 4D/A
channel 4PS
main
Non-isolated
digital I/O

Multiple Clock Sources
The DAC488HR/4 features four internal clock sources andaccommodates an external clock source (up to 10 MHz) for
updating the output ports. A 16‑bit counter is used to provide
update rates to meet application requirements. For example, the200 kHz clock and the 5 MHz clock can be divided down to any
rate between 3 Hz and 100 kHz for general purpose applications;the 5.6448 MHz clock can simulate 44.1 kHz audio CD signals;
and the 6.144 MHz clock can simulate 48 kHz audio DAT signals.
For synchronizing external circuitry to DAC488HR/4 output, anupdate clock signal is also provided.

Mainprocessor
digitalcircuitryInternal
peripheral
interfacebusIEEE 488
interface

Each DAC488HR/4 output port features a separate microprocessor andbuffer memory for independent waveform managementa single cycle. Additionally, for applications that exceed theDAC488HR/4’s internal buffer capacity, waveforms can be output
continuously from an IEEE 488 controller at up to 200 Kbytes/s
via the IEEE 488 bus.

Buffer Management
The DAC488HR/4’s step, burst, waveform, and continuous trigger output modes can be used with flexible buffer management
functions to output stepped voltages, any one of five standard
waveforms, or user‑defined arbitrary waveforms. Waveforms areloaded from the IEEE 488 bus into the DAC488HR/4’s resident
8 Ksample buffer at rates up to 500 Kbytes/s.

Nonvolatile Storage
The DAC488HR/4 uses resident nonvolatile random access memory(NVRAM) to store the calibration constants determined during­digital calibration, and to store its power‑up default ­configuration.

To output standard predefined sine, square, and triangle waveforms, the user specifies the starting memory location, numberof samples, max/min values, duty cycle, and the number of times
the cycle is to be repeated or “looped.” The “looping” ­function
outputs specified buffer segments up to the full available bufferedsize for repetition up to 65,535 times. This conserves memory
space by allowing long periodic waveforms to be defined in(508) 946-5100

D/Achannel 1Powersource 2

Multiple Trigger Sources

Measurement Computing

Nonisolated2

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DAC488HR/4
General Information
Functional Requirement

Waveform(s)Typical Application

Continuously output a standard
wave function under program
controlStandard function generator
outputs for general purpose
applications

Output a series of voltage values
based on TTL triggers

Sequenced V out for controlling
power supplies or other analog
programmable instruments
T1

Initiate a trigger delay from 1 to65,535 update clock pulses

T2

T3

T4

Analog output signal
trigger event

Allows a device under test (DUT)
to attain a steady state prior tomeasurement

trigger delaySynchronously output multiple
waveforms under program
control

Ideal for stimulus/response
applications with critical timeand phase relationships

Output a standard waveform
acquired by the ADC488/A Series
digitizer

Ideal for simulating complex
signals such as EKGs andcontact bounce

Continuously output a large
arbitrary waveform from the IEEE488 bus at up to 200 Kbytes/s

For audio system testing, speechresearch, and other tests
requiring long-time waveformgeneration

Stimulus/Response System Multi-DAC488HR/4
When configured with an ADC488/A Series Synchronization
A/D converter, the DAC488HR/4 is wellsuited for stimulus/response testing. For
synchronous operation in which acquisition must begin simultaneously with thestimulus output, the DAC488HR/4’s TTL
trigger output is connected directly with
the ADC488/A’s TTL trigger input; for nonsynchronous operation in which acquisition must begin at a specified time after
the stimulus output, the DAC488HR/4’strigger output can be “delayed” up to65,535 ­update clock counts.

Multiple DAC488HR/4s can be configured
in master/slave mode to synchronouslyoutput data either from their ­internalbuffers, or continuously from the IEEE488 bus. When daisy-chained together
the number of DAC488HR/4s in a system
is limited only by the number of available IEEE 488 addresses, and the trigger“latency” between each unit is 60 ns*.
For applications that require non-additive
trigger latencies, the DAC488HR/4s can beconfigured in parallel, limiting total system
trigger latency to 60 ns.

* A system with one master and three slave units will have a total system trigger latency of 180 ns

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DAC488HR/4

Specifications & Ordering Information
Specifications

Data Storage and Output
Data Buffer: 8 Ksamples standard (per channel); 480 Ksample option (per channel)
Data Format: ASCII, integer decimal, hexadecimal, and binary
Output Modes: Direct, step, burst, waveform, and continuous
Trigger Sources: GET, periodic time interval, external (TTL-level), and command
Trigger Latency: Daisy-chain mode; 60 ns (additive per unit) Parallel mode;
60 ns (non-additive system maximum)

Analog Output
Number of Channels: 4DC Output Voltage/Resolution
1V Range: ±1V, 30.5 µV/bit
2V Range: ±2V, 61 µV/bit
5V Range: ±5V, 152 µV/bit
10V Range: ±10V, 305 µV/bit
DC Output Current: ±10 mA max
Accuracy (25 ±5 ˚C)±0.025% of range
Polarity: Unipolar or bipolar (software selectable)
Output Impedance: 10 Ohm
Zero Offset: 50 to 500 µV
Linearity: 0.005%
Differential Linearity: 0.001%
Update Rate: 100 Ksamples/s (max per channel); all signals from the data buffer
are 100 Ksamples/s max; any single channel from the IEEE 488 bus to output
is 100 Ksamples/s max; any two channels from the IEEE 488 bus to output
are 50 Ksamples/s max; any two channels from the IEEE 488 bus to multiple
DAC488HR/4’s are 20 Ksample/s
Settling Time: 6 µs to 0.003% FSR
Temperature Coefficient: (±0.002% ±100 µV)/˚C; 0 to 20 ˚C, 20 to 30 ˚C, and30 to 50 ˚CChannel-to-Channel Isolation: 500V max
Channel-to-Digital Common and Chassis Isolation: 500V max
Connectors: DB9 (female) per channel; mating connector suppliedGeneral
Power: 90 to 125 or 210 to 250 VAC, 50/60 Hz; 20 VA max
Environment: 0 to 50 ˚C; 0 to 95% RH, non‑condensing
Controls: Power switch, external dip switch for IEEE address
Dimensions: 425 mm W x 305 mm D x 45 mm H (16.75” x 12” x 1.75”)
Weight: 3.6 kg (7.9 lbs)
Supplied Accessories: Analog output connector, digital I/O port connector

Ordering Information

Description
Isolated 4-channel converter with 8 Ksample memory
per channel; includes analog output connector;
digital I/O port connector; and rack-mount kit

Part No.
DAC488HR/4

Accessories & Cables
Shielded IEEE 488 cable, 6 ft.

CA‑7‑3Digital I/ODigital Inputs: 8 TTL-level compatible, external TTL trigger, external TTL clock input
Digital Outputs: 8 TTL-level compatible, also configurable as open collector with
100 mA drive, and delayed trigger output signal, update clock output.
Connectors: DB15 (female) per input and output port; mating connector supplied

IEEE 488 Specifications
Interface Subsets: SH1, AH1, T6, TE6, L4, LE4, SR1, PP0, RL0, DC1, DT2, C0, and E2Connector: Standard IEEE 488 connector with metric studs

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