Transducer Installation
Page 15
August 2019
DPP-UM-00256-EN-03
Probe Cables
Before inserting the probe into the pipe, the sensor cables should be routed to the transmitter location Verify that the
supplied cable length is sufficient to meet the installation requirements While transducer cable extension is not generally
recommended, if additional transducer cable length is required, use cable and connectors of the correct type and
impedance In many cases, especially if a splice my be exposed to water or other liquids, it may be more effective to replace
the entire cable Transducers use RG59, 75 Ohm coaxial cable, Twinax (Belden #9463) or (Belden # 9463DB) 78 Ohm
two-conductor cable
CAUTION
THE PROBE CABLES ARE DESIGNED TO CARRY LOW LEVEL SIGNALS THAT ARE DEVELOPED BY THE SENSOR. CARE
SHOULD BE TAKEN IN ROUTING THE CABLES. AVOID RUNNING CABLES NEAR SOURCES OF HIGH VOLTAGE OR EMI/RFI.
ALSO AVOID ROUTING THE CABLES IN CABLE TRAY CONFIGURATIONS, UNLESS THE TRAYS ARE SPECIFICALLY USED
FOR OTHER LOW VOLTAGE, LOW LEVEL SIGNAL CABLES.
CAUTION
THE INTERNAL DP7 PROBE WIRING IS EPOXY ENCAPSULATED TO SEAL IT FROM MOISTURE. THE DP7 PROBE IS
PROVIDED WITH TWO COAXIAL CABLES TO SHIELD THE LOW LEVEL SIGNALS AND MUST BE CONTINUOUS TO THE DP7
PROBE TRANSMITTER. EXCESS WIRE MAY BE CUTOFF OR SIMPLY COILED NEAR THE DFX FLOW METER.
Probe Oetraction Procedure
1 Retract the probe by loosening the upper jam nuts counterclockwise as viewed from the top of the probe using the proper
size wrench If the pipe is under pressure, the nuts must be turned alternately about two turns at a time to prevent binding
as a result of non-equal seal loading In many cases, the line pressure causes the probe to retract Should the probe bind,
use the retraction nuts on the lower side of the probe flange to assist in the probe retraction Continue this procedure until
the probe is fully retracted into the isolation valve
CAUTION
DO NOT RUN THE DRIVE NUTS OFF THE RODS UNTIL THE ISOLATION VALVE IS FULLY CLOSED.
2 After the probe is retracted past the “ball” in the isolation valve, the isolation valve may be closed to isolate the probe from
the line so the probe can be removed entirely
CAUTION
IF THE INSERTION PROBE IS NOT ABOVE THE “BALL” OF THE ISOLATION VALVE, THE VALVE CANNOT BE CLOSED. IF
THE VALVE WILL NOT CLOSE SMOOTHLY, THE BODY OR TIP OF THE PROBE IS MOST LIKELY NOT ABOVE THE “BALL”.
ATTEMPTING TO FORCE THE VALVE INTO THE CLOSED POSITION MAY RESULT IN DAMAGE TO THE PROBE.
