Correct wiring is the foundation of reliable ACE969 TP2 communication. This page provides detailed terminal wiring instructions, covering RS485 signal connections, cable shield grounding, and wiring to common upstream devices such as the Schneider Electric G3200 communication gateway.
The ACE969 TP2 RS485 interface provides two signal terminals: A (+) and B (−). These follow the same polarity convention as all other devices on the bus: A (+) connects to A (+), and B (−) connects to B (−). Reversed polarity causes communication failure or device damage.
Terminal Reference
- Terminal A (+): RS485 differential signal positive, connect to bus A wire
- Terminal B (−): RS485 differential signal negative, connect to bus B wire
- Shield terminal: cable shield grounding point — single-point ground at the control panel side only
- Install 120 Ω termination resistors at the first and last device on the bus
Wiring to Schneider G3200 Gateway
- G3200 TX+ (pin 1) → ACE969 TP2 terminal A
- G3200 TX− (pin 2) → ACE969 TP2 terminal B
- G3200 RX+ (pin 3) → ACE969 TP2 terminal A (parallel)
- G3200 RX− (pin 4) → ACE969 TP2 terminal B (parallel)
- Shield (pin 5): ground at G3200 side only; leave ACE969 TP2 side floating
"RS485 cable shields must be grounded at a single point only. Multi-point grounding creates ground loop currents that severely degrade communication quality."
For field wiring, use shielded twisted-pair cable with a minimum cross-section of 0.5 mm² and maintain at least 200 mm separation from power cables. For runs exceeding 300 m, reduce the baud rate to 9600 bps to ensure communication stability.
