VM600 MPS hardware manual (standard version) MAMPS-HW/E 14 - 3
Edition 17 - February 2018
Detecting problems due to front-end components and cabling
MAINTENANCE AND TROUBLESHOOTING
14.5Detecting problems due to front-end components and cabling
A front-end problem may be due to:
1- A defective transducer and signal conditioner.
2- Incorrect cabling of the transducer.
3- Cabling between the transducer and the signal conditioner and the MPS becoming
damaged (for example, open-circuit or short-circuit).
4- Incorrect configuration of the input transducer using the VM600 MPS software.
5- A problem with an external power supply (if used), leading to incorrect powering of the
transducer, signal conditioner and/or galvanic separation unit.
Any of the above faults will be signalled on the panel of the MPC4 or AMC8 card by one of
the following:
• The card’s DIAG/STATUS indicator (a multi-function, multi-colour LED).
• The status indicator(s) for the individual channel(s) in question (also multi-function,
multi-colour LEDs).
See Figure 2-7 and 4.9 Operation of LEDs on MPC4 panel for further information.
See Figure 2-9 and 5.10 Operation of LEDs on AMC8 panel for further information.
Cabling problems
Two categories can be observed:
1- The corresponding status indicator on the panel of the MPC4 or AMC8 card blinks green
continuously.
This indicates a continuous problem, for example, incorrect cabling.
2- The corresponding status indicator on the panel of the MPC4 or AMC8 card blinks green
intermittently.
This indicates an intermittent problem, for example, poor electrical contact.
Spikes may be observed on the signal output (for example, by studying the signal on the
corresponding BNC connector on the panel of MPC4 card).
NOTE: The risk of having cabling problems will be reduced if good wiring practice is
observed when installing the hardware.
External power supply failures
Replace the suspect external power supply by one from your spare parts stock. If this solves
the problem, the original power supply can be considered defective.
14.5.1 Replacing a suspect front-end component or cable
If a front-end problem has been traced to a particular measurement channel, then the channel
inhibit function can be used to temporarily bypass the sensor (that is, temporarily inhibit the
protection offered by any associated relays) while the other machinery monitoring channels
and functions continue to operate as normal.
This allows components in a particular measurement channel front-end (such as a
sensor/transducer, signal conditioner and/or cable) to be replaced while the machinery being
monitored continues to operate (if the protection offered by the other machinery monitoring
channels and functions is adequate). It also allows any control system using the relays to
avoid false trips during such maintenance activity.