PTCL Detected Error (OC/SC)

What does PtFL mean?

A PTCL (Positive Temperature Coefficient Logic) detected error, indicating either an open circuit (OC) or short circuit (SC) in the PTC probe circuit connected to logic input LI6. This prevents the drive from accurately monitoring motor temperature, risking motor overheating.

• Open circuit in the PTC thermistor wiring between the motor and the drive's LI6 input (e.g., a wire break or loose terminal connection).
• Short circuit across the PTC thermistor terminals or its connecting cable (e.g., damaged insulation, bare wires touching).
• PTC thermistor probe failure (e.g., internal element open or shorted) within the motor windings.
• Incorrect wiring of the PTC thermistor to a standard logic input (e.g., LI6) without proper parameter configuration (P3-0X for LI6 function).
• Drive's logic input LI6 hardware failure or internal protective component damage affecting resistance measurement.

Click steps to track your progress.

1. 1

   Isolate power, disconnect the PTC probe from LI6, and measure the resistance directly across the PTC thermistor leads at the drive end using a multimeter.

2. 2

   Compare the measured resistance value to the expected range for a healthy PTC thermistor (e.g., 20-250 Ohms cold, > 1650 Ohms hot).

3. 3

   Perform a continuity test on the PTC cabling from the motor to the drive's LI6 terminal to identify any breaks or shorts in the cable.

4. 4

   Ensure that Parameter P3-0X (e.g., P3-06 if LI6 is used) is correctly configured for "PTC input" (e.g., value 11 or 12 depending on drive model).

5. 5

   If the PTC thermistor resistance is within expected ranges and wiring is good, verify the voltage on LI6 changes according to PTC resistance (e.g., 24VDC when cold, 0VDC when tripped).