Problem
Causes and Solutions
The controller does not maintain
controller parameters or parame-
ters are reset each time the
power to the unit is removed
Note:
Before performing the memory check,you need to record the
controller calibration parameters (found in the CAL menu of the instru-
ment) and any user-adjusted parameters that you have changed
(such as the programmable set points and proportional band).
Memory Check
Doing a memory check is the easiest way to verify the ability of the
battery to maintain controller parameters.
1. Power off the instrument.
2. Disconnect the instrument from AC power for 10 seconds.
3. Reconnect the AC power and power on the instrument.
4. If the display shows InIT and/or the cycle count shows a low num-
ber such as 0002, the battery is spent and should be replaced. Con-
tact an Authorized Service Center for assistance.
5. After replacing the battery, you must reprogram the calibration and
user-adjustable parameters into the controller.
The controller shows that the out-
put power is steady but the pro-
cess temperature is unstable
If the bath temperature does not achieve the expected degree of sta-
bility when measured using a thermometer, try adjusting the propor-
tional band to a narrower width as discussed in Section 9.9,
Proportional Band.
The controller alternately heats
for a while then cools
The proportional band being too narrow typically causes this oscilla-
tion. Increase the width of the proportional band until the temperature
stabilizes as discussed in Section 9.9, Proportional Band.
The controller erratically heats
then cools, control is unstable
If both the bath temperature and output power do not vary periodically
but in a very erratic manner, the problem may be excess noise in the
system. Noise due to the control sensor should be less than 0.001°C.
However, if the probe has been damaged or has developed an inter-
mittent short, erratic behavior may exist. Check for a damaged probe
or poor connection between the probe and bath.
Intermittent shorts in the heater or controller electronic circuitry may
also be a possible cause. Contact an Authorized Service Center (see
Section 1.3) for assistance.
13.2
Comments
13.2.1
EMC Directive
The instrument was designed specifically as a test and measuring device. Com-
pliance to the EMC directive is through IEC 61326-1 Electrical equipment for
measurement, control and laboratory use - EMC requirements (1998).
As noted in the IEC 61326-1, the instrument can have varying configurations.
The instrument was tested in a typical configuration with shielded RS-232
cables.
13.2.1.1
Immunity Testing
The instrument was tested for laboratory locations. Criterion B was used for
Radiated RF (IEC 61000-4-3) and Voltage dips, short interruptions and voltage
immunity tests (IEC 61000-4-11). Criterion C was used for Electrostatic Dis-
charge (ESD, IEC 61000-4-2). If the instrument is subjected to ESD conditions,
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13 Troubleshooting
Comments