SKF Multilog IMx-S Series User Manual page 34

Troubleshooting Guide
Component Check
5. The cable or the sensor is probably damaged. Test the cabling by disconnecting
6. Cable is probably damaged. However, first try disconnecting one of the poles
7. Does the fault remain after replacing the sensor?
Checking speed input
1. Determine the unit number and speed input of the channel in question through
2. Measure the signal on the IMx-S terminal block using an oscilloscope or
3. Is there an expected speed signal on the IMx-S terminal block?
6 - 6
at the sensor end and connecting e.g. a 1.5 V battery. Does the input now
measure the voltage?
YES: The sensor is probably not functioning correctly. However, first check that
the channel is correctly configured according to the terminating resistor. In the
list of terminal blocks, it can be determined whether the channel in question
has a terminating resistor for current circuit. Check that this corresponds in
reality, and that it corresponds to the sensor's mode of operation.
NO: The cabling is probably damaged. Continue to step 6.
on the cable from the IMx-S terminal block. If the voltage is Ok, then the fault
is in the IMx-S unit input stage. Otherwise, the cable is damaged and needs to
be repaired.
YES: The fault can be in the analogue input part of the IMx-S unit. Contact SKF
Condition Monitoring Center Luleå.
NO: It is a sensor fault. Replace the sensor.
the software measurement point setting or through the list of terminal blocks.
similar. Make sure to use a potential free oscilloscope.
YES: The signal can be too weak or at too high impedance for the IMx-S speed
input to be triggered. Sufficient voltage ripple (peak to peak) is shown in the
electrical specifications. If the signal level is sufficient, then the IMx-S input is
defective or the software is incorrectly configured. Check the settings in the
program for the unit number and input number of the speed measurement
point. Contact SKF Condition Monitoring Center Luleå for consultation.
NO: The cable is damaged, or the sensor is not sending the correct output
signal. Check that the installation of the sensor is correct (is the machine
rotating?). If this produces no result, check the cable. The entire chain from
cable to input can be tested by linking a signal generator with a suitable
frequency and amplitude at the sensor end. However, note that IMx-S
normally supplies power to a sensor (as shown in the equipment list), which is
why a coupling capacitor must then be connected in series, to avoid ruining the
signal generator.
SKF Multilog On-Line System IMx-S
User Manual