The serial interface of the basic CH1 module CP-1003 and CP-1091 is firmly fitted with the RS-485 interface without galvanic isolation (i.e. the interface signals have galvanic connection with the module power supply, with the CIB interface, the TCL2 and the analogue inputs in the basic CP-1003 and CP-1091) modules. A view of the terminal block (in standard operating position of PLC on the control panel) is shown in Fig. .1.
Fig. 1 The terminal block A – connection of the interface CH1, RS-485.
The signal ground GND of the interface is a common terminal for the module power supply, the CIB bus and the TCL2 (it is also common with the negative common terminal of AI inputs).
Using interfaces is described in the manual TXV 001 06.
The RS-485 (CH1) interface is firmly terminated in the module with appropriate impedance and it must always be at the end of the RS-485 line (the same applies for the TCL2 interface in the Foxtrot basic module).