Installation and Commissioning

Troubleshooting ToolsRS 422SignalTXD4/TXD4 NRXD4/RXD4 NDATA4/DATA4 NDCLK4/DCLK4 NExplanationTransmit Data in Full Duplex ModeReceive Data in Full Duplex ModeData Signals in Half Duplex ModeData Transmission ClockN.B! Only full duplex is supported.5 VSignal XXX5 VSignal XXX Nf= 9600 38400 baudFigure 3 Signal description for RS 422, differential transmission.When measuring the differential RS 422 signals, the oscilloscope should be set for ACtesting. The data transmission has the same structure as RS 232, i.e. 1 start bit + 8 databits + 1 stop bit, but the signals are differential. By looking at the “true” channel, it ispossible to read the data.If the types of signal as shown in the above diagram are obtained when measuring, thismeans that the drive circuits and lines are OK. If one or both of the signals do not move,it is likely that one or several line(s) or one or several drive circuit(s) is/are faulty.32 Product Manual