The PLC 1775-SR is the Input/Output (I/O) scanner module for PLC-3/10 programmable logic controllers. The 1775-SR provides four communication channels for I/O which can be used to communicate with a maximum of 2048 outputs and 2048 inputs. A maximum of 16 I/O chassis can communicate with the one I/O channel on the 1775-SR. The 1775-SR is a module which must be installed in each PLC-3/10 system. When the 1775-SR is installed into the PLC-3/10 chassis, its thumbwheel should be set to 1. The 1775-SR provides a communication functionality between the primary PCL-3/10 and the following modules/systems: industrial terminal used for programming, 1771 I/O chassis, the backup PLC-3/10 processor (in event of primary PLC-3/10 processor failure) and with a maximum 6 PLC-3/10 or PLC-3 peer processors.
The 1775-SR includes an integrated RS-232-C port for communication with an industrial terminal which can be used for PLC-3/10 programming (via ladder diagrams), data table value entry and monitoring, the operation of LIST functions, and ladder diagram printing. A second 1775-SR module can be installed in the processor chassis to provide RS-232-C functionality and an additional four I/O communication channels. For the second 1775-SR module, the thumbwheel should be set to 2. Note that the addition of a second 1775-SR module does not lead to an increase in the number of I/O which the PLC can manage. The 1775-SR provides 4 I/O channels or 3 I/O channels and 1 RS-232-C port. For the RS-232-C port, the supported baud rates are 110 baud – 19.2 kbaud while for the I/O channel the rates are 57.6 kbaud (supports 10,000 feet of cable) or 115.2 kbaud (supports 5,000 feet of cable). To prevent equipment damage and operator injury, system power to the PLC-3/10 chassis should be removed prior to installing/removing the 1775-SR into the PLC-3/10 chassis. The 1775-SR is not compatible with PLC-3 controllers. The operating temperature range for the 1775-SR is 0 to 60 °C.
