We have s7-300 PLC used as a control system for a Loading unit. Data collected are transferred to an industrial PC via profibus cable from the PLC comm card to the PC. What will be the status of the switch located at cable sockets in both ends (PLC card End and PC End)?
Profibus is a daisy-chain network. The standard connectors (for inside cabinets) have space for 2 cables, with graphics molded into the casing to show which position to use if there's only one cable. The "on/off" switch is for the terminating resistor. If the device is at the end of the daisy chain, there will be only one cable in the connector, and the resistor switch should be ON. If it's in the middle of the daisy chain, there will be 2 cables in the connector and the resistor switch should be OFF.
There is only one cable from PLC Module to the PC, so will the switch position will be ON in both terminals or for the PC terminal only?