Watlow EZ-ZONE ® RME (Expansion) Module

4. Communication and networking functions (system linkage capability)

(1) Support protocols and topology

Applicable scenarios for key parameters of communication protocol physical interface

Watlow Standard Bus EIA-485 (Slot C terminal: CF=common terminal, CD=T -/R -, CE=T+/R+) supports 17 nodes, with a maximum transmission distance of 1200 meters (shielded twisted pair) and a default baud rate of 9600bps for internal communication between modules, used for data exchange between RME and RMC/RMA

Modbus RTU EIA-485/232 (Slot C terminal: CC=common terminal, CA=T -/R -, CB=T+/R+) supports 247 nodes, baud rate 9600/19200/38400bps, 8-bit data bits, optional checksum (none/odd/even), communicates with PLC and HMI, uploads I/O status and alarm information, receives control commands

Extended protocol (RMA module required) Ethernet/EIA-485 supports EtherNet/IP, DeviceNet, PROFIBUS DP large-scale system networking, enabling remote monitoring and centralized control

(2) Networking standards and limitations

Topology requirement: EIA-485 adopts a "daisy chain" topology, and star/tree connections are prohibited. The first and last modules need to be connected to 120 Ω terminal resistors (to reduce signal reflection).

Wiring requirements: Communication lines and power lines should be wired separately (with a spacing of ≥ 10cm), using shielded twisted pair cables (such as CAT5 and above), and the shielding layer should be grounded at one end (grounded on the control room side and suspended on the site side).

Distance limit: EIA-485 has a maximum transmission distance of 1200 meters, while EIA-232 has a maximum transmission distance of 15 meters; When installing Split Rail, the maximum distance of Inter module Bus is 200 feet, and independent power supply is required to avoid voltage drop.

Installation and Wiring Guide

1. Installation process and precautions

(1) DIN rail installation (mainstream method)

Guide rail preparation: Confirm that the guide rail meets the EN50022 standard (35 × 7.5mm), clean the surface of the guide rail without oil stains or rust, and ensure that the guide rail is grounded (grounding resistance ≤ 4 Ω) if installed in a hazardous area.

Module fixation:

Insert the top hook of the module into the upper edge of the guide rail, rotate the module to a vertical position, and hear a "click" sound to indicate that the buckle is locked.

When installing multiple modules, horizontally splice the modules to ensure that the backplane connectors are fully in contact (without gaps). After installing the last module, check the overall flatness to avoid tilting.

Space reservation: A space of ≥ 76.2mm should be reserved at the top, bottom, and front of the module for heat dissipation and wiring operations; Avoid direct proximity to heating devices such as heaters and frequency converters (with a spacing of ≥ 150mm).

(2) Panel installation (optional)

Use the matching panel installation bracket (specified separately when ordering), drill holes according to the installation hole positions provided in the manual (spacing 58.67mm × 51.56mm), fix with # 8 × 3/4 inch screws, torque 10-15 in lb, and do not use washers (to avoid loose installation).

2. Wiring specifications and terminal definitions

(1) Core terminal function (Slot C is the common terminal, Slot A/B/D/E is the I/O terminal)

Terminal group terminal number functional wiring requirements

Slot C 98 power input+connect 20.4-30.8V AC/DC, distinguish polarity, and prohibit reverse connection; Suggest connecting 1A slow melting fuses in series

Slot C 99 power input - connected to the negative pole of the power supply. If it is powered by AC, the polarity of the neutral/live wire needs to be confirmed

Slot C CF/CD/CE Standard Bus CF=common terminal, CD=T-/R-，CE=T+/R+； Using shielded twisted pair cables, daisy chain connection, with 120 Ω resistors connected at both ends

Slot C CC/CA/CB Modbus RTU CC=common terminal, CA=T-/R-，CB=T+/R+； Support EIA-485/232 switching, requires configuration through module buttons

During the installation of Slot C CZ/CX/CY Inter module Bus, connect two rails using shielded twisted pair cables and single ended grounding

Slot A/B/D/E digital I/O terminals (such as B1/D1/D2...) digital input/output input: B1 is connected to the common terminal, D1-D6 is connected to the signal; Output: B1 is connected to the common terminal, D1-D6 are connected to the load; Need to distinguish between dry contacts/voltage input types

Slot A/B/D/E CT input terminals (such as T1/S1...) The current transformer inputs T1/S1 form a group and are connected to the secondary side of the CT; Ensure CT polarity is correct to avoid measurement errors

Slot A/B/D/E relay/SSR terminal (such as L1/K1...) relay/SSR output L1 is a normally open contact, K1 is a common terminal; AC loads need to distinguish between live and neutral wires, while DC loads need to distinguish between positive and negative poles

Slot A/B/D/E process output terminals (such as F1/H1...) process/retransmission output F1=voltage/current -, H1=voltage/current+; Select voltage or current output according to the configuration, and match the load impedance