Patent ID: 7698103

Claim:
A physical layer diagnostic system for a modular fieldbus board carrying two or more fieldbuses, the two or more fieldbuses each including a power supply converter and a power conditioner and the two or more fieldbuses connected to a bulk power supply via the power supply converter and power conditioner for each of the two or more fieldbuses, the system comprising a monitoring transceiver connected in use to the two or more fieldbuses in which each connection to each of the two or more fieldbuses comprises two or more common mode and/or differential mode signal injection and/or signal detection points, which points are collectively formed to inject and/or detect both common mode and/or differential mode signals, and wherein first points of the common mode and/or differential mode signal injection and/or signal detection points are located between the bulk power supply and the power supply converter of each of the two or more fieldbuses and second points of the common mode and/or differential mode signal injection and/or signal detection points are located between the power conditioner and a fieldbus trunk part of each of the two or more fieldbuses, such that the monitoring transceiver can detect one or more fieldbus physical layer characteristics between two of the two or more of said points, and in which the monitoring transceiver is provided with a first digital and/or analog interface adapted to transmit physical layer diagnostic data detected by the monitoring transceiver directly to an associated digital or analog device.