Ametek Drexelbrook Universal IV CM, Installation And Operating Instructions Manual

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Normal Maintenance
49
Section 5
Problem /Symptom Tests in order of
probability
Reference Comments
No display on DCM Check power Section 2.2.2
No display on U-IV CM Check power at DCM
Check power at UIV-CM Section 2.2.2
U-IV CM manual
Can’t communicate HART with
DCM using Drexelbrook PC
Software
Check modem is connected to
correct loop connections
Check for 250 Ω resistance (min.)
in the loop.
Check voltage at DCM
Try another modem
Power from a battery source
Section 2.2.2 Often a result of loop connection
problems or output current > 20
mA
0 mA output all the time
(no measurable output current at
any time)
Check voltage at transmitter
Check polarity of loop Section 2.2.2 Probable loop problem.
Faulty connection in loop
No Modbus communication Verify wiring on terminals A and B Section 2.2.2 Wiring/polarity incorrect
More than 20 mA output all the
time Check display for error message
Check for moisture in housing Table 5-2 Probable fault condition
Output erratic - (output jumps
around noticeably in terms of
seconds or minutes)
Check probe and cable
Check for radio interference
Check for noise on loop U-IV CM manual Erratic readings often show actual
process conditions. Look for
bubbles. stratification, etc
Output intermittent (output jumps
quickly usually between >4mA
and some “on scale” value
Check signal loop connections
Possible water slug Section 2.2.2 Intermittent loop connection
Inaccurate readings (% water
readings are incorrect compared
to sample)
Check calibration
Check method of comparison Section 3.2
Reading does not change with
water cut Check cables
Check sensing element
Check LRV/URV
U-IV CM manual Verify % water reading
URV too high
Output goes in opposite direction
from water cut change Check LRV/URV Configuration Menu Table Probable LRV/URV reversal
Table 5.1