INSTALLATION AND OPERATING INSTRUCTIONS
Troubleshooting
42 (66)
SKF Multilog On-line System IMx-16Plus
User Manual
Revision Letter A
2. Disconnect one signal wire from the terminal/connector and recomplete the
circuit using a DMM set in current measurement mode.
Does the measured mA current reasonably agree with the expected value?
YES: Problem appears to be related to the IMx (hardware, installation or
configuration). If on rechecking the aspects advised above, no reason for the
measurement error is found, contact TSG for advice.
NO: Problem appears to be related to the signal loop connected to the IMx
input. Continue with further checks on the source equipment and the integrity
of the interconnecting cables.
2.9.3.3 Checking PT1000 channels
PT1000 sensors have a nominal resistance of 1 k
Ω
at 0
0
C and change resistance
with temperature. The sensor is linearised to give a response of 3,85
Ω
per
0
C
(positive coefficient = increasing resistance with higher temperatures). During SAT
testing or to prove the measurement loop, the sensor can be replaced by a 1 k
Ω SAT
1. Identify the input terminals where the channel in question is connected to the
IMx-16Plus and verify that this a channel in the range 9 to 16. Confirm sensor
type in the configuration is set at PT1000 (C) or PT1000 (F). If all appears
OK, measure the DC voltage (V) across the channel input using a digital
voltmeter. From this measurement calculate an approximate temperature as
follows:
T (
0
C) = ((V / 0,00223)
–
1000) / 3,85 [nominal sense current is 2,23 mA]
Is the calculated temperature within the expected measurement range and
does it agree (approximately) with that displayed by the system?
YES: Continue to step
NO: Problem appears to be related to the IMx (hardware, installation or
configuration). If after rechecking these aspects, (and confirming sensor loop
resistance is reasonable, step 2), no reason for the measurement error is
found, contact TSG for advice.
2. Disconnecting the sensor and measuring its resistance (R
Ω)
using a DMM
can give a good indication of whether the sensor is providing a reasonable
indication of the temperature and whether there are any major issues such as
an open or short circuit in the sensor or cabling.
T (
0
C) = (R
–
1000) / 3.85