Practical Instrument Electronics 850 - Manual (Page 22)

Page 20
Pr
eliminar
y
The PIE 850 is supplying
the loop voltage. There is a
control loop error. This may
be a transmitter (set for
upscale burnout) with a
bad or missing sensor, or a
short in the loop. The PIE 850 is supplying
the loop voltage. A
calibrated transmitter is
limiting the loop current to
12.00 mA. An additional
0.28 mA is not controlled
by the transmitter and is
leaking somewhere in the
loop.
PWRM LEAK
00.28 mA
12.280
mA
Typical Error Conditions
Typical
2-Wire
Transmitter
+ IN - REF +OUT-
Transmitter Input
Sensor
Process Signal
Simulated Input
12.280
PROCESS
INDICATOR
12.280
mA
PWRM LEAK
5 6 + -
00.28 mA
Using Ground Leak Detection
PWRM LEAK
mA
OVER RANGE
mA
Note: Many installed transmitters will normally indicate 0.01 to
0.02 mA leakage without significant control problem. Unstable
readings may indicate loose connections or the presence of
moisture.