Component Check - SKF Multilog On-line System IMx-T User Manual

Component Check

Checking sensor and sensor cabling for analogue channels
1. Determine the unit number and channel number of the channel in question
2. Measure the DC voltage between the sensor wires on the IMx-T terminal block
Sensor type
Standard accelerometer
3. Is the voltage within the normal working range?
4. Does the fault remain after changing the sensor?
5. Is the voltage close to zero (typical < ±0.5 V)?
6. Did the voltage rise to normal open circuit voltage?
7. Is the sensor a standard type?
8. The fault is in the sensor cable or the sensor. Go out to the sensor, and
SKF Multilog On-line System IMx-T
User Manual, Revision F
through the measurement point information in the software, or through the list
of terminal blocks.
using a digital voltmeter. See the table below for the normal voltage values
with and without a connected sensor respectively.
Normal operating bias
voltage (DC V)
8 to 12 V
Table 6-12:
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.
YES: The fault may be in the analogue input section of the IMx-T unit. Contact
SKF Condition Monitoring Center Luleå for service and further
information.
NO: Sensor fault. The sensor is defective and must be replaced.
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-T unit.
NO: Continue to step 9.
YES: Continue to step 8.
NO: The sensor is not receiving power, continue below.
YES: These are powered internally from the IMx-T unit. If the IMx-T unit does
not supply open circuit voltage with input open, then the IMx-T input is
probably damaged, or the input is not configured to supply a power feed
to the sensor. Contact SKF Condition Monitoring Center Luleå.
disconnect the cable at this end. Reconnect the cable on the IMx-T 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.
Open circuit voltage (DC V)
+24 V
Normal voltage
Troubleshooting Guide
Component Check
6-35