D8500 Modbus Analog Output Module


The D8500 analog output modules contain two outputs for controlling annunciators, valves and more.  Each analog output can be programmed as either a voltage or current output by selecting one of four ranges: 0-10Vdc, +/-10Vdc, 0-20mA and +/-20mA.

The analog output uses a 12-bit digital to analog converter for generating the output signal. The output signals are updated as a supervisory computer transmits digital data values to the module. The data values are scaled in 16-bit unsigned integer data format that represents a percentage of full scale. See the Modbus scaling example link below.

The D8500 analog output module contains a user-programmable communications watchdog timer. The watchdog timer can be used to force the analog outputs to a known “safe” condition in the event of a communications lost to the module. The “safe” condition value can be specified in the Initial Value register.

All digital data values are transmitted using the Modbus RTU serial protocol via the USB virtual serial port connection.

Download Datasheet

Download Manual

Modbus Scaling Overview

The D8500 USB analog output modules can be mounted on a DIN-rail using the MK-1 mounting kit.

Available on backorder

Additional Information

Dimensions 7.14 × 4 × 1.5 in
Voltage Ranges

0-10Vdc, +/-10Vdc

Current Ranges

0-20mA and +/-20mA


• 2CH Analog Output Module.
• USB communications interface.
• Modbus RTU Protocol.
• 500Vrms analog output isolation.
• 12-bit Analog Output Resolution.
• Continuous self-calibration
• Requires +10V to +30Vdc unregulated supply, 2.1W.
• Removable screw terminal plug connectors.
• CE marked.
• Communications Watchdog Timer
• User Programmable Initial Analog Output Value
• 250 Conversions per second
• 8-bit ADC Analog Output signal Readback
• 3ft USB cable included.


The D8500 analog output modules are compatible with all commercial software programs and OPC servers that support the Modbus RTU serial protocol. Commercials software programs from Wonderware, DreamReport, Indusoft, DAQFactory and Dasylab all support the Modbus RTU protocol. OPC Servers from Kepware and MatrikonOPC support the Modbus RTU protocol.


• Process monitoring and control
• Data logging to any host computer
• Product testing

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