2. Associate correct functional instances
3. Repair the load short circuit and replace the overloaded equipment
4. Replace the relay module or SSR component (original spare parts are required)
Alarm not triggered, a.st displays "None". 1. Alarm threshold setting error (above/below normal range)
2. Alarm source selection error (sr.a=None)
3. Alarm blocking enabled (a.bL=Startup/Set Point)
4. The alarm lag is too large (a.hy>deviation value). 1. Enter Operations → Alarm Menu and compare the process value with the alarm threshold
2. Enter Setup → Alarm Menu, confirm that "sr.a" selects the correct source (such as Digital I/O, Current)
3. Check if "a.bL" is "Off" and if the blockage is lifted after startup
4. Reduce the "a.hy" value (such as changing from 5 ℃ to 1 ℃). 1. Adjust the alarm threshold to ensure coverage of the abnormal range
2. Select the correct alarm source and associate it with an instance
3. Turn off the alarm blocking or wait for the blocking time to end
4. Adjust the lag to a reasonable value
(2) Meaning of indicator lights and fault logs
Indicator light status meaning investigation direction
Power (green) is constantly on, and the power supply is normal-
Power (red) constantly on. Abnormal power supply (overvoltage/undervoltage, short circuit). Measure the power supply voltage and check the power supply wiring
Comm (green) flashing (once/second) communication active, data exchange normal-
Comm (red) constantly on communication fault (address error, wiring error, protocol mismatch). Check communication parameters and wiring
SD Card (green) flashing SD card read/write in progress-
SD Card (red) always on. SD card fault (unrecognized, damaged, full storage). Re insert and unplug the SD card, format or replace it, and clear the log
Fault log viewing: Go to Factory → Diagnostics Menu and check the "Error Code" (such as "E01=Communication Fault" and "E02=Output Short Circuit") “Software ID”“Serial Number”, After recording the information, contact Watlow technical support for troubleshooting.
Typical application scenarios
1. I/O expansion of semiconductor wafer heat treatment equipment
System composition: 1 RMA (EtherNet/IP gateway)+2 RMCs (temperature control, controlling wafer heating chamber)+3 RMEs (I/O expansion) deployed in semiconductor cleanrooms.
Function implementation:
RME1: Connect 16 digital inputs (chamber door switch, wafer in place sensor) and 8 SSR outputs (driving chamber heating lamp).
RME2: Connect 8 CT inputs (monitor heating lamp current) and 4 process outputs (control nitrogen flow valve).
RME3: Implement interlocking protection for "door not closed → heating stop" and "abnormal current → alarm" through logical operations, and control the duration of wafer heating through timing function.
Value: Distributed I/O reduces cleanroom wiring, logical interlocking enhances equipment safety, and EtherNet/IP enables data exchange with MES systems.
2. Temperature and valve control of chemical reaction kettle
System composition: 1 RMA (Class 1 Div. 2 certification)+1 RMC (temperature control)+1 RME (special equipment control), deployed in the chemical explosion-proof workshop.
Function implementation:
RMC controls the temperature of the reaction vessel, while RME drives the feed valve through the "Motorized Valve" function, configured with "Valve Travel Time=120 seconds" and "Dead Band=2%" to avoid frequent valve adjustments.
RME is connected to 4 CT inputs to monitor the current of the mixing motor. When the current is abnormal, an alarm is triggered and the feeding valve is cut off.
Explosion proof junction boxes and armored shielded wires are used, which comply with Class 1 Div. 2 safety requirements and prohibit live plugging and unplugging of wires.
Value: Explosion proof design suitable for hazardous areas, precise valve control to enhance reaction stability, current monitoring to prevent equipment failure.
3. Timing control of food processing production line
System composition: 1 RMA (Modbus RTU)+1 RMC (oven temperature control)+2 RME (timing and logic control), used for biscuit baking production line.
Function implementation:
RME1: Use the "Sequencer" function to distribute the oven heating power into 4 outputs (1 vernier+3 ON/OFF), use the "Progressive" mode to balance heater wear, and set "Minimum On Time=60 seconds".
RME2: Control the speed of the conveyor belt through timing function (linked to the temperature of the oven), and implement the interlock of "oven not reaching temperature → conveyor belt stop" through logical operation.
PLC reads the production line status through Modbus RTU and issues start stop commands.
Value: Sequencer function extends heater life, timing interlock improves production efficiency, Modbus communication enables centralized monitoring.

Email:wang@kongjiangauto.com