Chapter 14 Fault Codes and Descriptions
ME300 
 
  No.  Display on LED Keypad  Fault Name  Fault Descriptions 
72 
 
S1 internal loop 
detection error (STL1) 
S1–DCM internal loop detection error 
Action and Reset 
Action condition  Hardware detection 
Action time  Immediately act 
Fault treatment parameter  N/A 
Reset method  Hardware failure, and cannot reset. Cycle the power. 
Reset condition  N/A 
Record  Yes 
Cause  Corrective Actions 
STO jumper cap is not installed or 
is off. 
Install the jumper cap. 
External STO card S1 and +24V   
short circuit line are not connected.
Check the wiring of the S1 and +24V terminal. 
External STO card is installed 
incorrectly or pin fractures. 
Check if STO card is correctly installed. 
Insufficient external input voltage  Check that the input voltage maintains at least 11V. 
False trigger  Reset the emergency switch (ON: activated) and cycle the power. 
Hardware failure 
After you make sure all the wiring is correct, if STL1 fault still exists after cycling 
the power, please contact Delta.