Skip To Content

D8400 Modbus Analog Input Module


The D8400 analog input module contains seven isolated differential inputs for measuring voltages, thermocouple temperature sensors and current signals such as 4-20mA. Each module can measure six different voltage ranges between +/-25mV and +/-10Vdc, one current range and eight thermocouple types. The thermocouple types include J, K, T, E, R, S, B and C types.

The D8400 analog input module performs a 16-bit analog to digital conversion on each input channel, linearizes the digital data and formats the result in a 16-bit unsigned integer format. The unsigned integer values represent a percentage of full-scale input range. See the Modbus scaling example link below.

The digital data values are transmitted to a host computer using the Modbus RTU serial protocol via the USB virtual serial port connection.

Download Datasheet

Download Manual

Modbus Scaling Overview

The D8400 USB analog input 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

+/-25mV, +/-50mV, +/-100mV, +/-1V, +/-5V, +/-10V

Current Range


Thermocouple Types

J, K, T, E, R, S, B and C


• User-selectable analog input range per channel.
• USB communications interface.
• Modbus RTU Protocol.
• 500Vrms analog input isolation.
• 16-bit analog input measurement resolution.
• Continuous self-calibration
• Programmable analog input digital filters.
• Requires +10V to +30Vdc unregulated supply, 1.4W.
• Removable screw terminal plug connectors.
• 3ft USB cable included.
• CE marked.
• 7CH Differential Volt, TC, Current Input Module


The D8400 series analog input module is compatible with all commercial software programs and OPC servers that support the Modbus RTU protocol. Commercials software programs from Wonderware, Intellution, National Instruments Labview, 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