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DI-900 Modbus Distributed Data AcquisitionMulti-Channel Discrete I/O Modules
Active-High Inputs Sourcing Outputs (High-Side Switching)

  • Standard Modbus RTU protocol with high-speed RS-485 communication (up to 115K bps)
  • Twelve I/O channels in a single inch-wide unit reduces system costs and saves panel space
  • High-voltage, high-current, open-source outputs enable direct (high-side) control of external devices
  • High-voltage buffered inputs monitor discrete levels from a variety of industrial devices
  • Tandem input/output circuitry (DI-906MB models only) connects input buffers with open-source outputs for convenient loopback monitoring of the output state
  • Watchdog timers provide a configurable failsafe output state for use when host I/O communication is lost
  • Three-way isolation eliminates potential ground loops between power, I/O, and network circuitry
  • Self-diagnostics monitor microcontroller activity to detect operational failures (lock-up) and execute a reset to restore communication.

Data Sheet


Product Highlights

These modules provide twelve discrete input and/or output channels. Isolation separates the I/O, power, and network circuits. Network communication adheres to the industry-standard RS-485 Modbus RTU protocol. Both AC and DC power sources are supported with wide range, nonpolarized, diode-coupled terminals.

The outputs are intended for current-sourcing or high-side switching applications. The buffered inputs are active-high. These models are the complement of the DI-901MB, DI-902MB, and DI-903MB units which have low-side output switches and active-low inputs. Socketed pull-down resistors are easily removed or exchanged to satisfy your application requirements. See the Circuit Connection Diagrams.

Combining flexible I/O types, wide I/O ranges, and a network interface in a single package, makes this instrument extremely powerful. Multi-channel design adds cost-efficiency and allows high-density mounting. Plus, safe, rugged construction makes these modules reliable for use in both control room and distributed field I/O applications. Custom module configurations are also possible (consult factory for details).

Everything you need to complete your network is available from DATAQ Instruments, Inc. - isolators, signal converters, signal boosters, power sources, and mounting hardware. Check out the Accessories.