Schneider Electric ACE949-2 RS485 Interface Module

Configured for Engineering or Supervisory Local Area Network Modbus RTU communication in Sepam protection relay systems, the Schneider Electric ACE949-2 (ACE949-2 RS485 interface module) provides direct physical/electrical execution for 2-wire RS485 data exchange between Sepam series devices and external supervisory nodes.

Suffix Breakdown & Model Matrix

No suffix segmentation applies. The ACE949-2 is a fixed single-order RS485 interface module with no configurable model variants defined in the provided specification.

Hardware Specifications

Protocol Conversion Latency and Serial Bus Determinism Characteristics (Schneider Electric Control Integration Layer)

The ACE949-2 implements RS485 physical layer coupling for Sepam series 20 / 40 / 60 / 80 relay networks. Signal transmission follows Modbus RTU framing over 2-wire differential bus architecture. Deterministic timing is constrained by half-duplex arbitration and line loading.

Bus segmentation supports multi-device topologies with cable length scaling from 100 m to 1000 m depending on node count and supply voltage. Electrical signaling remains dependent on terminal biasing and line termination matching at RS485 endpoints. Communication stability is influenced by topology density and cumulative propagation delay across chained devices.

Frequently Asked Questions (FAQ)

Q: Does ACE949-2 support hot-swapping on RS485 Modbus networks? A: No hot-swap mechanism is defined. Bus reconnection requires idle line state and proper termination stability before reintegration.

Q: What is the impact of maximum node loading on signal timing? A: Increasing device count increases frame arbitration delay and reduces effective bus segment length due to electrical loading.

Q: Does the module require external power supply? A: No. Power is directly supplied by the connected Sepam unit via defined DC supply range.

Field Installation Guidelines

RS485 wiring must use twisted shielded pair conductors with controlled impedance routing. Maintain correct A/B polarity across all nodes. Shield termination should be grounded at a single reference point to avoid ground loop currents.

DIN rail mounting requires full mechanical engagement across the symmetrical rail interface. Ensure minimum bending radius compliance for RS485 cable at enclosure entry.

Termination resistors must be applied only at physical bus endpoints. Intermediate nodes must remain unterminated to preserve signal integrity across the multidrop topology.