User Manual
MEAS LT Level & Pressure Transducer User Manual
Measurement Specialties, Inc.
www.meas-spec.com
1-757-766-1500
1000 Lucas Way, Hampton, VA 23666 USA
21 of 31
1-800-745-8008
Batteries are suggested to power the transducer during testing to eliminate the possibility that line noise is
passing through an improperly filtered, grounded, or damaged installation power supply.
The meter should be a digital type capable of reading at least 2 digits to the right of the decimal point.
A second instrument should be available to confirm the observations. A handheld Digital Multi-Meter
(DMM) capable of reading 4-20 mA of current, or 0-20 VDC to a resolution of at least 0.01 decimal
places.
Once your transducer is correctly configured per one of the diagrams
, orient the transducer in a vertical
position with the pressure port down
and then read the zero output on your meter. For a 0-5 VDC
output, the zero should be between 0 and 0.25 volts, and for a 4-20 mA output, between 3.75 and 4.25
mA. If the transducer is submersible, you may opt to test the unit’s response in a container of room
temperature water and observe its reaction to liquid pressure. It should return to the same zero point
when removed. If the output is outside of these limits, note the results and continue to troubleshoot the
transducer per the suggested measurements shown below.
Case check:
These checks (diagrams on the next page) are performed to detect internal shorts either in wiring that
might have made contact with the structural components of the transducer, or from water intrusion that
has made its way to the internal circuit board. In either case, there should be zero (0) voltage output on
the case when the tests below are performed and checked with a Digital Multi-meter.
Further Measurements:
The following checks to the wiring should be made using a Digital Multi-Meter to insure that all connection
wiring offer the listed resistance levels for proper operation.
All measurements outlined here should be recorded and sent to Measurement Specialties. We will
review it with you, and determine if further evaluation is necessary. If so, an RMA (Return Material
Authorization) number will be established, and you will be asked to send the results along with the
transducer to assist in the RMA evaluation process. Measurement Specialties Customer Service
Department can be reached at (800) 745-8008, or
0-5 VDC
Should read:
4-20 mA
Should read:
+Excitation (red) to Shield
(drain)
> 2.5 Mohms
+Excitation (red) to Shield
(drain)
> 2.5 Mohms
-Excitation (black) to Shield
(drain)
> 2.5 Mohms
-Excitation (black) to Shield
(drain)
> 2.5 Mohms
+Output (white) to Shield (drain) > 2.5 Mohms
Shield (drain) to Housing
< 2 ohms
Shield (blue) to Housing
< 2 ohms
