The PD 662 Redundant P-NET Interface is one of a number of standard modules within the PD 600 series range. Its main purpose is to provide a redundant and transparent link between optical Light-Link and a duplicated RS-485 P-NET. The module frequently scans the RS-485 communication links to check if the communication networks are functioning correctly. The PD 662 will ensure that the local cluster of modules (i.e. the device, in which the PD 662 itself is a component) will receive data from one of the two RS-485 P-NET ports, and that data from the local cluster will be transmitted on both RS-485 P-NET ports. If, for example, P-NET port 1 is used, and a short circuit or a cable break is detected, the PD 662 will automatically switch to P-NET port 2. The module itself does not require any programming, but a P-NET slave address and a few other parameters must be configured. The PD 662 is used with a BM 010 base module