Hardware Manual

Saia-Burgess Controls AG

Hardware Manual PCD 1 / PCD 2 Series│Document 26 / 737│Edition EN 15│2008-07-22

Appendix A

A

A-4

Definitions of serial interfaces

A.2.3 TTY / current loop

Signals to  TTY /   current loop

Terminal 11 TS Transmitter Source

Terminal 13 TA Transmitter Anode Transmitter

Terminal 16 TC Transmitter Cathode

Terminal 18 TG Transmitter Ground

Terminal 12 RS Receiver Source

Terminal 14 RA Receiver Anode Receiver

Terminal 17 RC Receiver Cathode

Terminal 19 RG Receiver Ground

Signal type Required value Nominal value

Power for logic L (space) -20 mA to + 2 mA 0 mA

Power for logic H (mark) +12 mA to +24 mA +20 mA

Neutral voltage to TS, RS +16 V to +24 V +24 V

Short circuit power on TS, RS +18 mA to +29.6 mA +23.2 mA

The idle state of the data signals = “mark”

By wiring to the cable connector, the user selects either an “active” or “passive” cir-

cuit.

The max. transmission rate for 20 mA TTY / current loops is 9600 bps.