Honeywell SC1000 - Manual (Page 122)

page 122 008-0608-00
12.8 Troubleshooting
12.8.1 Error Messages
See “Error Messages” on page 151 for information relating to error messages.
12.8.2 Common Problems
and Solutions
Erratic Display Check electrical connections for continuity and the transducer’s and/or amplifier’s
wiring code from its Certificate of Calibration and Application Note.
Incorrect wiring may have shorted the excitation power supply. Use the correct
wiring diagram to connect the transducer or amplifier to the instrument.
Make sure that the load on the transducer is constant.
Check input voltage or current to the (+)Signal (“+SIG”) and (-)Signal (“-SIG”) pins
with a multi-meter.
Blank Display Incorrect wiring may have shorted the ±15 VDC excitation power supply. Use the
correct wiring diagram to connect the transducer or amplifier to the instrument.
+OVLD or -OVLD on Display Indicates that the voltage across the (+)Signal (“+SIG”) and (-)Signal (“-SIG”) pins
is overranging or underranging the amplifier circuit. Make certain all wires are
connected properly.
If you remove all load from the transducer and you still see this message, the
(+)Excitation (“+EXC”) or (-)Excitation (“-EXC”) pins may be shorted to the (+)Sig-
nal (“+SIG”) or (-)Signal (“-SIG”) pins.
If you remove all load from the transducer and you get a numeric reading, the
transducer may have a high zero offset. Use the channel’s SETUP menu and set
DIAGNOSTICS
->
DISPLAY ADC
to “ON”; in the RUN mode this will allow the [VALUE] but-
ton to display raw A/D readings as a percentage of its full-scale. If the raw A/D
readings display more than +/-10% when there is no load on the transducer, the
transducer has a high zero offset.
Analog Output Incorrect Make certain of the type of Analog Output (voltage or current) that the channel is
equipped with; see “Identifying the Output Type” on page 121.
Use the
DIAGNOSTICS
->
DAC FULL SCALE
and
DIAGNOSTICS
->
DAC ZERO SCALE
menu items to
force the Analog Output to a known output. Then, adjust your readout device,
panel meter, PLC or data acquisition system to match.
Check the output selection jumpers; see “Output Selection” on page 121.
Auxiliary Function Pins Not
Operating Make sure that the
AUX1 FUNCTION
or
AUX2 FUNCTION
SETUP menu items are set cor-
rectly; if they are set to
DISABLED
then they will not operate.
The Auxiliary Function (“AUX1” and “AUX2”) pins must be connected to pin 10,
not pin 8, to activate them.
Sensitivity to EMI/RFI To obtain maximum immunity to electromagnetic or radio frequency interference,
make certain that the shields of the transducer cables are connected to the “cable
shield connection screw” on the rear panel of the instrument. See “Wiring” on
page 98, “External Arrangement of AC powered SC1000 and SC2000” on
page 27 and “External Arrangement of Model SC3004” on page 33.