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• REV C
(Sept 2017) Page
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The buffered output common is protected against ground loop currents affecting the current
loop output with a 10kΩ resistance between the buffered output common and the loop
common.
Metrix recommends using a ground isolated instrument or signal isolator. The meter, oscil-
loscope or analyzer used to measure the gap voltage or to observe the vibration signal
(DYNAMIC OUTPUT) must have an input impedance of one megohm or greater.
The scale factor of the output signal is 200 mV/ mil.
Metrix recommends a maximum cable length of 15 ft (5 m) when connecting to the buffered
output due to noise susceptibility caused by the high input and output impedances.
4. VERIFICATION AND CALIBRATION
This section describes the steps to verify proper DPS operation and to custom calibrate your
DPS to your specific probe and cable.
CAUTION:
When using the MX2034 BNC connector, exer-
cise special care to prevent ground loops that could alter
the 4-20mA output, resulting in spurious alarms or ma-
chine trips. Such ground loops can occur when connecting
to grounded test equipment or multiple input test equip-
ment. Metrix recommends use only with ungrounded test
equipment, such as battery-powered portable meters,
or grounded test equipment with differential inputs (i.e.,
neither side of input connection is tied to ground). Also,
cable lengths between the BNC connector and test equip-
ment should be kept suitably short (5m or less) to prevent
unwanted noise.
NOTE:
The DPS requires the probe and extension cables be
from the configured probe series, combine to the config-
ured system length, and view the configured target mate-
rial in order to meet system range and accuracy