Fluke 9116A User Manual page 79

9116A Furnace
User's Guide
78
Problem
The display flashes
"Cut-out" and an incorrect
process temperature
The displayed process
temperature is in error and
the controller remains in
the cooling or heating
state at any set-point value
Causes and Solutions
The problem may be that the controller's voltmeter circuit is not function-
ing properly.
A problem with the thermocouple probe, the cutout operation, or the cut-
out circuitry may cause the cutout to remain in this condition.
Check that the thermocouple probe is plugged into the controller and
wired correctly. Check that the probe temperature is well below the pro-
grammed set-point. If not then reset the cutout temperature to a value
well above the probe temperature or wait for the temperature to cool well
below the cutout set-point. If the cutout is set for manual reset mode then
after the temperature cools the user must also manually reset the cutout
according to the directions in this manual under Section 6.9, Cutout. If the
probe is not connected to the controller, plug in the appropriate thermo-
couple probe into the cutout probe socket.
A nearby large static discharge may also affect data in memory. Verify
that the parameters on the Report of Test are accurate. Cycle the power
off, disconnect the instrument from AC, and then restart the instrument.
The controller may need to be reset using the Factory Reset Sequence
listed below, but should only be performed if a current Report of Test is
available, since performing the Factory Reset Sequence sets all controller
parameters to default.
Factory Reset Sequence. Hold the SET and EXIT buttons down at the
same time while powering up the instrument. The instrument display
shows '-init-', the model number, and the firmware version. Each of the
controller parameters and calibration constants must be reprogrammed.
The values can be found on the Report of Test that was shipped with the
instrument.
Possible causes may be either a faulty control probe or erroneous data in
memory.
The probe may be disconnected, shorted, or burned out.
Check that the probe is connected properly. If wired properly, the probe
may be checked with an ohmmeter to see if it is open or shorted. The
probe is a platinum 4-wire Din 43760 type. The resistance should read 0.2
to 2.0 ohms between pins 1 and 2 on the probe connector and 0.2 to 2.0
ohms between pins 3 and 4. It should read 10 [at 0°C (32°F)] to 50 ohms
[at 1100°C (32°F)] between pins 1 and 4 depending on the temperature of
the instrument. If the probe appears to be defective, contact an Autho-
rized Service Center (see Section 1.4) for assistance.
If the problem is not the probe, erroneous data in memory may be the
cause. Re-initialize the memory as discussed in the problem 'The display
flashes "Cut-out" and an incorrect process temperature'. If the problem re-
mains, the cause may be a defective electronic component.