InSpec Sampler Controller SECTION 24: FIELD CONNECTIONS
24.3.2 RS422 & RS485 TERMINATION
For correct operation of the multi-drop bus, the communication lines must be held in the default
fault tolerant position. For RS422 this is done at each receiver and Rx+ is pulled low (0V) and Rx- is
pulled high (5V).For RS485 this is done at each transceiver and Tx/Rx+ is pulled low (0V) and Tx/Rx- is
pulled high (5V). See Section 3.13 for information on configuring this option.
24.3.3 RS422 & RS485 CONNECTIONS
Figure 50 - RS422 (4-Wire)
Figure 51 - RS485 (2-Wire)
24.4 PLUG NO. 6
IMPORTANT: Cables terminating into Pulse Inputs or Analogue Inputs/Outputs in this terminal block must be
screened and kept separate from the digital I/O.
This terminal block is carries connections for: -
• 1 off 24V DC Supply;
• 4 off Digital I/O points;
• 2 off Pulse Inputs (Voltage or Current Pulse);
• 2 off Analogue Outputs;
• 3 off Analogue Inputs
Its terminal assignments are:e a