Comments; Emc Directive; Immunity Testing - Fluke 7341 User Manual

7341 Calibration Bath
User's Guide
13.2
13.2.1
13.2.1.1
74
Problem
The controller erratically heats
then cools, control is unstable
The bath does not achieve low
temperatures

Comments

EMC Directive

Hart Scientific's equipment has been tested to meet the European Electromag-
netic Compatibility Directive (EMCEMC Directive, 89/336/EEC). The Decla-
ration of Conformity for your instrument lists the specific standards to which
the unit was tested.
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.

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,
the instrument may require the user to cycle the power to return to normal
operation.
Causes and Solutions
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. The probe is located inside
the stirrer motor cover.
•
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 Au-
thorized Service Center (see Section 1.3, on page 5) for
assistance.
Too much heating or not enough cooling can cause this problem.
•
Check that the control indicator glows green showing
that the controller is attempting to cool. The heaters may
be disabled as a test by temporarily removing the heater
fuses.
•
Insufficient cooling may be caused by lack of refrigerant.
Contact an Authorized Service Center for assistance.