Watlow Watbus System: PM PLUS, EZ-ZONE RM & ASPYRE AT

Entherm sells and supports Watlow temperature and power controls as a connected system. Watbus links PM PLUS panel controllers, EZ-ZONE RM DIN-rail modules, RMA PLUS remote access, and ASPYRE AT smart SCR power controllers into one thermal loop. Heat demand travels over the bus instead of discrete wires. COMPOSER® provides configuration and monitoring; RMA PLUS provides plant Ethernet access.

WHAT WATBUS IS

Watbus is Watlow’s proprietary RS-485 token-passing network. High-speed inter-module bus connects compatible RM modules and ASPYRE AT at CY, CX, CZ terminals. Low-speed standard bus serves PM / PM PLUS, RUI, and ST. RMA PLUS bridges traffic; PM PLUS CE, CD, CF terminals can link to ASPYRE AT when set to Backplane Bus.

SYSTEM BUILDING BLOCKS

PM PLUS: panel-mount PID/operator interface. Runs the process loop, sends heat demand to ASPYRE AT over inter-module bus without a discrete heat-output wire, and displays heater measurements when configured.

EZ-ZONE RM: DIN-rail multi-loop, control, limit, and modular I/O stack for multi-zone density and expansion.

RMA PLUS: remote access/Ethernet gateway with managed switch, two user Ethernet jacks, Watbus access over Ethernet and USB for COMPOSER, Modbus TCP/RTU gateway functions, and model-dependent EtherNet/IP and data logging. Shop: https://www.entherminc.com/shop/p/watlow-rma-plus-remote-access-module

ASPYRE AT: smart SCR power controller receiving set points from PM PLUS or RM over inter-module bus, with power measurements and diagnostics; up to 16 units per Watlow documentation.

HOW THEY WORK TOGETHER

Panel PID + SCR: Sensor → PM PLUS → inter-module bus → ASPYRE AT → heater. Multi-zone: sensors → EZ-ZONE RM stack → bus → multiple ASPYRE AT units → heaters. Add RMA PLUS for Ethernet/USB access, Modbus TCP, optional EtherNet/IP, and data logging.

TYPICAL APPLICATIONS

Multi-zone process heating panels, ovens, dryers, heated platens, packaging seal bars, heater-health diagnostics, panel conversions from discrete SSR wiring, and OEM machines needing PM PLUS door control with DIN-rail ASPYRE AT power.

WHY ENTHERM

System selection, local stock, configurable RMA PLUS, and engineering support for thermal loop design, panel layout, and commissioning. Entherm supports Watlow controllers, power controls, sensors, and heaters.