64 Honeywell Sensing and Control
Signal Conditioning, Self Calibrating Digital Indicators
Rev. G, 008-0608-00
12.8 Troubleshooting
12.8.1 Error Messages
See “Error Messages” on page 73 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
Incorrectwiringmayhaveshortedthe±15Vdcexcitationpower
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 (+)Signal (“+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
Figure 12-9: Digital-to-Analog Output Jumper Locations
channel’s SETUP menu and set DIAGNOSTICS -> DISPLAY ADC to
“ON”; in the RUN mode this will allow the [VALUE] button to dis-
play 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 63.
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 63.
Auxiliary Function Pins Not Operating
Make sure that the AUX1 FUNCTION or AUX2 FUNCTION SETUP menu
items are set correctly; if they are set to DISABLED then they will
not operate.
The Auxiliary Function (“AUX1” and “AUX2”) pins must be con-
nected to pin 10, not pin 8, to activate them.
Sensitivity to EMI/RFI
To obtain maximum immunity to electromagnetic or radio frequen-
cy 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 48,
“External Arrangement of AC powered SC2000” on page 10 and
“External Arrangement of Model SC3004” on page 15.
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