Troubleshooting Guide
Component Check
6 - 4
SKF Multilog On-Line System IMx-M
User Manual
3. Is the voltage within the normal working range?
YES: The cabling to the sensor is probably OK, and the sensor electronics have
normal input impedance. If the sensor signal is still not perceived to be
normal, one should try changing the sensor.
NO: Continue to step 5.
4. Does the fault remain after changing the sensor?
YES: The fault may be in the analog input section of the IMx-M rack. Contact SKF
Condition Monitoring Center Luleå for service and further information.
NO: Sensor fault. The sensor is defective and must be replaced.
5. Is the voltage close to zero (typical < ±0.5 V)?
YES: There is probably a short circuit in the cable, or the sensor is defective. First,
verify that the voltage rises to normal open circuit voltage when one of the
sensor cable poles is disconnected from the terminal block of the IMx-M rack.
NO: Continue to step 9.
6. Did the voltage rise to normal open circuit voltage?
YES: Continue to step 8.
NO: The sensor is not receiving power, continue below.
7. Is the sensor a standard type?
YES: These are powered internally from the IMx-M rack. If the IMx-M rack does not
supply open circuit voltage with input open, then the IMx-M input is probably
damaged, or the input is not configured to supply a power feed to the sensor.
Contact SKF Condition Monitoring Center Luleå.
8. The fault is in the sensor cable or the sensor. Go out to the sensor, and disconnect
the cable at this end. Reconnect the cable on the IMx-M terminal block, and again
measure the voltage over these two poles. Does the short circuit remain?
YES: The sensor cable (or contact) has a short circuit. Repair the cabling.
NO: The sensor is defective. Replace the sensor.
9. Is the voltage close to the open circuit voltage?
YES: There is a break in the cable or the sensor is damaged. Continue below.
NO: If the voltage appears to be neither within the normal working range, close to
zero nor close to open circuit voltage, then the fault is an unusual one. First,
check that the measurement was correctly carried out, then contact SKF
Condition Monitoring Center Luleå. Remaining faults can be due to a damaged
sensor or a damaged IMx-M input. First, disconnect one pole of the sensor
cable, and measure the open circuit voltage to verify whether the open circuit
voltage is normal. If it is normal, then the fault is probably in the sensor,
otherwise the fault is in IMx-M.