The D1700M digital I/O Series modules provide computer monitoring and control of industrial on/off signals and communicate the digital information using the Modbus RTU serial protocol. The modules provide fifteen I/O bits for sensing contact closures and controlling relays or annunciators. Two different pairs of modules are available in the D1700M series.
The D1701M and D1702M modules contain seven discrete digital inputs and eight open-collector digital outputs. The discrete inputs contain internal pull-up resistors allowing for direct connection of switches or contacts without the need for external components. The open-collector outputs can be used to control solid-state relays or annunciators. The outputs can be pulled up to +30Vdc and drive 30mA loads without damage. Refer to the D1000M documents for more information.
The D1711M and D1712M modules contain fifteen discrete digital I/O bits. Each bit is user selectable as either a digital input or digital output. Each input can monitor digital signals between 0-30Vdc. The outputs can be pulled up to +30Vdc and drive 100mA loads without damage. Enhanced features of the D1711M and D1712M include a communications watchdog timer and a user-programmable starting value for each digital output. Refer to the D1700M documents for more information.
Each module contains either an RS-232 or RS-485 interface for direct connection to a host supervisory computer. Because the Modbus protocol does not support Echoing the RS-232 versions of D1000M series are limited to one module per serial port. Applications requiring more than one module should use RS-485.