Applicable Systems
ThyssenKrupp Control System
Symptoms
SR (safety relay) module error detected - code 20 TT
Possible Causes
- SR module hardware fault
- safety relay coil failure
- relay contact degradation
Troubleshooting Steps
- Step 1: Check SR module
Verify the fault is resolved after completing this step. - Step 2: inspect relay contacts
Verify the fault is resolved after completing this step. - Step 3: verify coil resistance
Verify the fault is resolved after completing this step. - Step 4: replace if faulty
Verify the fault is resolved after completing this step.
How to Reset
Power cycle; replace SR module if persistent
Source: beijiaxin.cn; zhihu.com/p/577262471; renrendoc MC2-C manual
Category: Elevator