Problem
Causes and Solutions
The display flashes “
cutout
”
and an incorrect process
temperature
The problem may be that the controller’s voltmeter circuit is not func-
tioning properly. A problem could exist with the memory back-up bat-
tery. If the battery voltage is insufficient to maintain the memory, data
may become scrambled causing problems. A nearby large static dis-
charge may also affect data in memory.
Holding the “SET” and “EXIT” keys down while power to the controller
is switched on may reset the memory. The display shows “—
init
—”
indicating the memory is being initialized. At this point, each of the
controller parameters and calibration constants must be repro-
grammed into memory. You can obtain the calibration constants from
Report of Test.
If the problem reoccurs, the battery should be replaced. Contact an
Authorized Service Center (see Section 1.3) for assistance. If
initializing the memory does not remedy the problem, there may be a
failed electronic component.
The displayed process tempera-
ture is in error and the controller
remains in the cooling or the
heating state at any set-point
value
Possible causes may be either a faulty control probe or erroneous
data in memory. The probe may be disconnected, burned out, or
shorted. Check that the probe is connected 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, therefore, the resistance
should read 0.2 to 2.0 ohms between pins 1 and 2 on the probe con-
nector and 0.2 to 2.0 ohms between pins 3 and 4. The resistance
should read from 100 to 300 ohms between pins 1 and 4 depending
on the temperature. If the probe is defective, contact an Authorized
Service Center (see Section 1.3) 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 dis-
play flashes “cutout” and an incorrect process temperature’.
If the
problem remains, the cause may be a defective electronic component,
contact an Authorized Service Center (see Section 1.3) for
assistance.
The controller controls or at-
tempts to control at an inaccurate
temperature
The controller operates normally except when controlling at a speci-
fied set-point. At this set-point, the temperature does not agree with
that measured by the user’s reference thermometer to within the spec-
ified accuracy. This problem may be caused by an actual difference in
temperature between the points where the control probe and ther-
mometer probe measure temperature, by erroneous bath calibration
parameters, or by a damaged control probe.
•
Check that the bath has an adequate amount of fluid in
the tank and that the stirrer is operating properly.
•
Check that the thermometer probe and control probe are
both fully inserted into the bath to minimize temperature
gradient errors.
•
Check that the calibration parameters are all correct ac-
cording to the Report of Test. If not, re-program the con-
stants. The memory backup battery may be weak
causing errors in data as described in the problem:
‘The
display flashes “cutout” and an incorrect process temper-
ature’.
•
Check that the control probe has not been struck, bent,
or damaged. If the cause of the problem remains un-
known, contact an Authorized Service Center (see Sec-
tion 1.3) for assistance.
6331 Calibration Bath
User’s Guide
72
