INSTALLATION AND OPERATING INSTRUCTIONS
Troubleshooting
44 (66)
SKF Multilog On-line System IMx-16Plus
User Manual
Revision Letter A
2.9.3.5 Checking digital channels
Effective troubleshooting for tacho signals will likely require a handheld/portable
oscilloscope or DMM with oscilloscope capabilities (a battery powered unit is
preferred). It will be hindered if the IMx-16Plus cannot be accessed when the speed
signal is active.
1. Check the sensor installation, the security of the mounting, the gap to the
target and the differential gap between target and no target, conditions.
Ensure these are acceptable for the sensor being used and that the sensor
output will cross the trigger threshold specified in
2. Identify the digital input terminals where the channel in question is connected
to the IMx-16Plus. Confirm that the wiring is correct for the sensor type in
use, see also
3. Is sensor power (supposed to be) supplied by the IMx-16Plus?
NO: Skip to step
, dynamic (oscilloscope) checks
YES: Measure the DC voltage between the P (power) and G (ground)
terminals using a digital voltmeter.
a. Is the measured voltage as expected? (typically, 24 V DC)
YES: Skip to step
, dynamic (oscilloscope) checks
NO: Disconnect the sensor cable from the P (power) terminal and
recheck the voltage.
b. Is the measured voltage now as expected? (typically, 24 V DC)
YES: Double check that the sensor is compatible (especially that the
sensor current requirement is within the capability of the IMx-16Plus).
To confirm a sensor/cable fault: if available try substituting an
alternative sensor or confirm that in a known working installation the
same type of s
ensor does not ‘load’ the IMx sensor power in this way.
NO: The test suggests a fault in the IMx-16Plus, contact TSG for
further advice.
4. When a speed signal is expected to be present, observe the signal at the D
(digital) and G (ground) terminals on an oscilloscope. Is the expected pulsed
waveform present?