901MB / 902MB / 903MB
Multi-Channel Modbus-RTU Discrete I/O Modules
• Active-Low Inputs, Sinking Outputs (Low-Side Switching)
• 12 input and/or 12 output channels
• 0 to 35V DC I/O range
• 10 to 36V DC, 24V AC power
• Modbus-RTU high-speed RS-485more >
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 open-drain outputs are intended for current-sinking or low-side switching applications. The buffered inputs are active-low. These models are the complement of the 904, 905, and 906 units which have open-source, high-side output switches and active-high inputs. Socketed pull-up resistors are easily removed or exchanged to satisfy your application requirements.
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).
Features & Benefits
• 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-drain outputs enable direct (low-side) control of external devices
• High-voltage buffered inputs monitor discrete levels from a variety of industrial devices
• Tandem input/output circuitry (903 models only) connects input buffers with open-drain outputs for convenient loopback monitoring of the output state
• Outputs have built-in over-temperature and over-current shut-down protection, plus active clamping circuits for switching inductive loads
• 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
• Operating temperature: -25°C to +70°C (-13°F to +158°F).