Product basic information and positioning
1. Core positioning
Watlow EZ-ZONE ® The RMA (Access) module is the functional extension core of the RM series controller, without independent PID control capability. It focuses on providing auxiliary functions such as multi protocol communication gateway, data recording, configuration backup, real-time clock, etc. It can be networked with RM modules such as RMC (controller), RME (extension), and RML (limit) to build a distributed control system with up to 17 modules (1 RMA+16 other RM modules), suitable for centralized monitoring and integration requirements of industrial heating, cooling, mixing and other processes.
2. Basic specifications
Category specific parameter description
Appearance and installation 155mm (width) × 116.08mm (height), weight 453.59g DIN rail installation (EN50022 standard, 35 × 7.5mm), vertical installation required, top/bottom/front reserved 76.2mm maintenance space, optional panel installation (customer provided fasteners)
Power supply requirements: 20.4-30.8V AC/DC, frequency 50/60Hz, Class 2 or SELV certified power supply, power consumption 4W (active)/9VA (apparent), supporting Semi F47-0200 voltage drop standard (resistant to grid fluctuations)
Environmental adaptability working temperature -18~65 ° C, storage temperature -40~85 ° C 0-90% RH (non condensing), protection level IP20, required to be installed in NEMA Type 1 or above protective enclosure
Certification Standard UL ®/ EN 61010, Class 1 Div. 2 (optional), RoHS, WEEE partial models certified FM Class 3545 (limit control version), ANSI/ISA 12.12.01-2007 (hazardous area)
Warranty and Support: 3-year warranty (for first-time buyers, not for misuse/modification scenarios) Technical Support: Phone (+1 (507) 494-5656, CST 7:00-17:00), email( wintechsupport@watlow.com )Local representatives; Returns require prior application for RMA number
3. Product identification and version
Document version: Rev. B, released in March 2016, model example: RMAX-A3BD-AAA (including EtherNet/IP+Modbus TCP, SD card backup, data recording function)
Hardware version: distinguished by Serial Number, software version (S.rL), firmware version (S.bLd) and other information can be viewed in the Factory menu

Core functions and technical features
1. Communication function (core expansion capability)
(1) Support protocols and interfaces
The RMA module is the communication hub of the RM system, supporting multi protocol compatibility and adapting to different industrial network architectures
Protocol Type Interface Specification Key Parameters Applicable Scenarios
Modbus ® RTU EIA-485/232 addresses 1-247, baud rate 9600/19200/38400bps, verify None/Even/Odd, support high and low byte order configuration for small PLC/PC networking, low-cost remote monitoring
Modbus ® TCP Ethernet (10/100Mbps) supports DHCP/fixed IP, port 502, and can enable factory level Ethernet monitoring and cross regional data exchange simultaneously with EtherNet/IP
EtherNet/IP ™ Ethernet supports implicit (real-time I/O) and explicit (configuration/diagnostic) communication, with up to 100 implicit members integrated into Rockwell PLC for real-time control scenarios
DeviceNet ™ CAN bus node address 0-63, baud rate 125/250/500kbps, supports Quick Connect for fast online networking of field devices (sensors/actuators), low-cost distributed control
PROFIBUS DP EIA-485 addresses 0-126, supports DP-V0 (cyclic communication)/DP-V1 (non cyclic communication), 120 Ω terminal resistor Siemens PLC integration, high reliability industrial scenarios
USB Mini Type B (v1.1) is recognized as a storage device, used for SD card data export, configuration file read/write local debugging, and fast backup of log data
Standard Bus EIA-485 (default) is standard for all RM modules, used for inter module communication, supports 17 node RM series module networking, and shares power and configuration
(2) Communication Network Design Specification
Topology: EIA-485 adopts a daisy chain topology to avoid star/ring connections and reduce signal reflection; Ethernet needs to be connected through a switch and supports 10/100Mbps adaptation.
Distance limit: EIA-485 maximum 1200 meters (shielded twisted pair), EIA-232 maximum 15 meters, Ethernet maximum 100 meters (CAT5 and above cables).
Terminal resistor: The head and tail modules of the EIA-485 bus need to be connected to a 120 Ω terminal resistor to reduce signal attenuation; PROFIBUS DP supports switching between internal and external terminal resistors.
Anti interference measures: Communication lines and power lines should be wired separately (with a spacing of ≥ 10cm), using shielded twisted pair cables, and the shielding layer should be grounded at one end (grounding resistance ≤ 4 Ω).
2. Data Logging function
(1) Core competencies
Storage medium: Comes standard with a 2GB Micro SD card (supporting larger capacity), with CSV (comma separated values) file format, and can be opened directly with Excel or Notepad.
Record range: up to 200 log points, supporting analog inputs (temperature/current), alarm status, process values, set points, and other data sources.
Email:wang@kongjiangauto.com