
46
CMC TECHNICAL REFERENCE MANUAL
1X36003 Version 2.52
1996-1999 Ingersoll-Rand Company
Date of Issue: 18-Oct-1999
Input/Output (I/O) System
Vibration Monitoring System (VMS)
Description:
The vibration transmitter is used to convert the proximity probe signal into a 4 -20 mA signal,
which is monitored by the CMC. The system is based on a 15-foot (4.575 m) total electrical
length.
Component specifications:
Transmitter:
•
100 mv/mil = 0.1 volt per 0.001 in (0.0254 mm)
•
4 mil (0.1016 mm) scale
•
4-20 mA output
Probe:
•
Gap setting 0.030 to 0.060 in (0.762 to 1.524 mm), 0.050 in (1.27 mm) is nominal gap
•
Probe gap corresponds to 3 to 6 volts VDC, 5 VDC nominal
•
Probe ohm value 7-12 ohms
Troubleshooting:
The following table identifies typical problems, probable causes, and appropriate procedures
for verifying the probable cause:
Typical Problem
Probable Cause
Troubleshooting Procedure
Zero OUI readout
Open circuit/cable disconnected VMS #2, 3, 4
(when compressor is
Loss of power to transmitter
VMS #1
running)
Malfunctioning transmitter
VMS #2
Transmitter not calibrated
VMS #2
Erratic OUI readout
Loose wire/terminal/connector
VMS #2, 3, 4
Incorrect OUI readout
Any
VMS #1, 2, 3, 4, 5