Analogue input I in < 4mA

What does 50 mean?

The analogue input configured for a 4-20 mA current loop is receiving a current signal below 4mA. This typically indicates a break or loose connection in the control cable, or a failure of the signal source device. Loss of the analogue signal means the drive cannot receive its intended reference or feedback, leading to incorrect control.

• Break or high resistance in the 4-20 mA current loop cable between the sensor/transmitter and the drive's analogue input terminal (e.g., AI1, AI2).
• Loose wiring connection at the drive's analogue input terminal or at the sensor/transmitter side.
• Power supply failure for the 4-20 mA transmitter (e.g., 24VDC supply missing or below tolerance).
• Sensor/transmitter failure, causing it to output less than 4mA or no signal.
• Incorrect scaling or configuration of the analogue input in the drive (e.g., P3-05 (AI1 min current) set incorrectly).

Click steps to track your progress.

1. 1

   Measure the current directly at the drive's analogue input terminals (e.g., AI1+, AI1-) using a multimeter in series.

2. 2

   Verify the 24VDC power supply voltage at the sensor/transmitter and at the drive's auxiliary output terminals (e.g., X1:7, X1:8).

3. 3

   Inspect the wiring connections at the drive's analogue input terminals (e.g., X1:5 for AI1) and at the external sensor/transmitter.

4. 4

   Disconnect the sensor and simulate a 4mA signal using a current calibrator to test the drive's input.

5. 5

   Check parameter P3-05 (Analogue input 1 minimum current) and P3-06 (Analogue input 1 maximum current) for correct configuration.

6. 6

   If available, temporarily replace the external sensor/transmitter with a known good unit.