INSTALLATION AND OPERATING INSTRUCTIONS
Troubleshooting
40 (63)
SKF Multilog On-line System IMx-8/IMx-8Plus
User Manual
Revision E
1. Identify the input terminals where the channel in question is connected to the
IMx and verify that the correct resistor is installed. If all appears OK, measure
the DC voltage (V) across the channel input using a digital voltmeter. Is the
voltage within the range 0.5 to 5.5 V DC?
NO: If the correct resistor is being used, the current is outside the expected
range for a 4-20 mA signal.
If the measured voltage is below the voltage range, continue to step
If the measured voltage is above the voltage range, replace with another load
resistor and recheck. If there is no change, check that it is a 4-20 mA current
signal that is being applied to the input, as a problem external to the IMx is
most likely indicated.
YES: The current is reasonably within the expected range for a 4-20 mA
signal. Estimate the equivalent current by calculating as follows:
Equivalent current (mA) = (V * 1000) / 250
Does this agree, approximately, with the mA value it is believed the external
circuit is transmitting?
NO: Continue to step
YES: The circuit and connections appear OK, double check the channel
assignment and its configuration and if no reason for the measurement error
is found, contact TSG for advice.
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 analogue input channels
Analogue inputs refer
to ‘other voltage inputs’
, not accelerometers or 4-20 mA
signals. In case of unexpected measurement values, check the channel configuration
especially scale, zero level and choice of engineering units. Ensure that the cable
check function enable/disable setting is appropriate for the signal applied.
1. Identify the input terminals where the channel in question is connected to the
IMx and verify that the connections are correct. If all appears OK, measure
the DC voltage (V) across the channel input using a digital voltmeter. Is the
voltage as expected, for the connected signal, type?
NO: Continue to step