5.4 Probe gap voltage confirmation
It will be necessary to confirm the probe gap voltage in the following circumstances.
• During installation/commissioning of the system.
• Thereafter annually (unless the gap voltage is continuously/regularly monitored).
• If a problem is suspected or the monitoring system indicates unexpected gap changes or
sensor fault.
The gap voltage can be confirmed in the following ways:
1
The system should have been powered for at least 5 minutes before performing any check
2
Measure the gap voltage by one or more of the following methods:
2.1
View the gap/bias voltage reported by the IMx/monitoring system
2.2
Use a DVM (Digital Voltmeter) to confirm the DC voltage measured at the monitor’s
input terminals
2.3
Use a DVM to confirm the DC voltage measured at the driver’s output terminals
3
If the probe is to be gapped/adjusted:
3.1
Loosen the jam nut of the probe.
3.2
Adjust the probe position so that the desired gap voltage is achieved.
3.3
After adjustment, be sure to tighten the jam nut of the probe at the specified torque.
C AUTION
Always tighten the jam/locknut nut to the specified torque (refer specifications).
If tightened with excessive torque, probe damage may result and if insufficiently tight-
ened, it may work loose from the mounting.
NOTE
The response indicated in Appendix B1 “Standard static characteristic” relates to a
SCM440 flat target (diameter more than 15 mm). When the target material or shape/size
differ, the output characteristics (gain) will change, and it may be necessary to compen-
sate at the monitoring system by use of an appropriate sensitivity, rather than the nomi-
nal/standard value.
30
30
Summary of Contents for CMSS 785 Series
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