A30920 — Power unit: Temperature sensor fault

The drive raises this message when evaluating the temperature sensor returns an error. The alarm value distinguishes the two conditions the manual names: the sensor circuit is interrupted or no sensor is connected (value 1), or the measured resistance at the sensor input is too low (value 2). The condition is issued as alarm A30920; depending on the drive's configuration it can also be raised as fault F30920. The manuals print the title Power unit: Temperature sensor fault and, in the G120/G120XA/G120C/G115D alarm and fault tables, Temperature sensor fault. Which resistance thresholds the drive applies to values 1 and 2 depends on the connected sensor type (KTY, PT100, PT1000 or PTC) and, for KTY and PT1000, on the product family — see the decoding below.

• The power unit detected an error while evaluating the connected temperature sensor.
• Value 1: wire breakage, or the sensor is not connected — the measured resistance lies above the threshold the drive applies to the sensor type (see the decoding below).
• Value 2: the measured resistance is too low, i.e. below the threshold for the sensor type.

1. Read the alarm value in r2124 (interpret decimal) to see whether the drive reports value 1 (wire breakage or sensor not connected) or value 2 (measured resistance too low).
2. Make sure that the sensor is connected correctly. On the power units described in the S120/S150 and G130/G150 manuals, a temperature sensor is connected to terminals X21.1/.2 or X22.1/.2 ("Booksize" format) or X41.4/.3 ("Chassis" format).
3. Compare the measured sensor resistance with the thresholds in the decoding below for the sensor type used (KTY, PT100, PT1000 or PTC).
4. Replace the sensor.

• The drive stores the message value as the alarm value in r2124; interpret it as a decimal number.
• 1 — wire breakage or sensor not connected. S120/S150 and G130/G150: KTY: R > 1630 Ohm, PT100: R > 375 Ohm, PT1000: R > 1720 Ohm. G120/G120XA: KTY: R > 2120 Ohm, PT1000: R > 2120 Ohm (no PT100 threshold printed).
• 2 — measured resistance too low. S120/S150 and G130/G150: PTC: R < 20 Ohm, KTY: R < 50 Ohm, PT100: R < 30 Ohm, PT1000: R < 603 Ohm. G120/G120XA: PTC: R < 20 Ohm, KTY: R < 50 Ohm, PT1000: R < 603 Ohm.

• r2124 — alarm value of this message: read it (interpret decimal) to tell value 1 (wire breakage or sensor not connected) from value 2 (measured resistance too low).

The manuals name no special reset for this message: as an alarm it requires no acknowledgement, and clearing the cause — reconnecting the sensor correctly or replacing it — is what matters. If the drive is configured to raise the same condition as fault F30920, it executes the off-responses assigned to the drive object (OFF1, OFF2, OFF3, IASC/DCBRK or STOP2) and the fault must be acknowledged IMMEDIATELY.