American Magnetics 175 Industrial Level Transmitter (CE-Marked) - Manual (Page 17)

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Drift Test
This test will determine if the transmitter or probe/application is the cause of a drifting (unstable)
output.
1.) Open the instrument housing and remove the electronic assembly (“puck”).
2.) Disconnect the probe wiring from the terminals on the base board.
3.) Connect a temperature stable (COG-type) 200pF capacitor between the “Probe”
and ground terminals.
4.) Observe the output over a 24-hour period. Check for stability.
5.) If the reading has drifted, contact the factory. If the reading is stable, either the
probe or the application must be the cause. Go the “Check Probe” section to test
the probe. If the probe is OK, contact the factory for application assistance.
System Loop Test
This test will determine is the correct voltage is available for the transmitter.
1.) Disconnect the loop wires from the transmitter.
2.) Use a voltmeter to measure the open circuit voltage of the loop. The value must be
between 12 and 30 Vdc.
3.) Reconnect the loop wires to the transmitter.
4.) Use a voltmeter to measure the voltage at the Loop (+) and Loop (-) terminals. The
value must be between 12 and 30 Vdc.
5.) If you don’t get these values, contact the factory for assistance.
Check Probe
This test will determine whether the probe is functional
Integral-mounted Units
1.) Open the instrument housing and remove the electronic assembly (“puck”).
2.) Disconnect the probe wiring from the terminals on the base board.
3.) Unscrew the Instrument Housing / Wiring Nipple assembly from the probe.
4.) Lower the process fluid level below the bottom of the probe. If this is not possible,
remove the probe from the process vessel. DO NOT remove any coating or
residue present on the probe.
5.) Use an Ohmmeter to measure the resistance between the center of the BNC
Connection at the top of the probe and the probe mounting nut.
6.) If the resistance is below 40Meg Ω wipe any coating or residue off the probe, and
repeat the measurement. If the reading is still below 40Meg Ω contact the factory.
“Live” electrical circuits can ignite flammable gasses and dusts. Insure
that the unit is properly grounded, and that a suitable intrinsically safe
barrier has been installed between the Power Supply and this unit.
WARNING !
“Live” electrical circuits can ignite flammable gasses and dusts. Insure
that the unit is properly grounded, and that a suitable intrinsically safe
barrier has been installed between the Power Supply and this unit.
WARNING !
“Live” electrical circuits can ignite flammable gasses and dusts. Insure
that power has been removed from the unit before performing this test.
WARNING
!