Ropex Resistron RES-407, Руководство по эксплуатации

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Startup and operation
Version 1 RES-407 Page 19
6.2.3 Configuration of the alarm output
(as of April 2005)
If the plug-jumper is not inserted - or if it is incorrectly inserted - an error message appears when
the controller is switched on (
 section 7.13 "Error messages" on page 34).
If the "Alarm output opened by alarm/PC CONFIGURATION" position is selected (as of April 2005), the behavior
of the alarm output can be configured in more detail by means of the ROPEX visualization software (
 see
section 7.11 "Diagnostic interface/visualization software (as of April 2005)" on page 33).
6.3 Replacing and "burning in" the heatsealing band
6.3.1 "Burning in" the heatsealing band
The heatsealing band is a key component in the control loop, since it is both a heating element and a sensor. The
geometry of the heatsealing band is too complex to be discussed at length here. We shall therefore only refer to
a few of the most important physical and electrical properties:
The measuring principle applied for this system necessitates a heatsealing band alloy with a suitable temperature
coefficient TCR. Too low a TCR leads to oscillation or uncontrolled heating.
When heatsealing bands with a higher TCR are used, the controller must be calibrated for this.
The first time the heatsealing band is heated to approximately 200…250°C, the standard alloy undergoes a once-
only resistance change (burn-in effect). The cold resistance of the heatsealing band is reduced by approximately
2…3%. However, this at first glance slight resistance change results in a zero point error of 20…30°C. The zero
point must therefore be corrected after a few heating cycles, i.e. the AUTOCAL function must be repeated.
The burn-in effect described here does not occur if the heatsealing band has already been thermally pretreated
by the manufacturer.
An overheated or burned-out heatsealing band must no longer be used because the TCR has been
altered irreversibly.
One very important design feature is the copper or silver-plating of the heatsealing band ends. Cold ends allow
the temperature to be controlled accurately and increase the life of the teflon coating and the heatsealing band.
6.3.2 Replacing the heatsealing band
All power supply leads must be disconnected from the RESISTRON
®
temperature controller in order
to replace the heatsealing band.
The heatsealing band must be replaced in accordance with the instructions provided by the manu-
facturer.
0
5
1
2
3
4
6
7
8
9
Alarm output opened
by alarm/
PC-CONFIGURATION.
Alarm output closed
by alarm.
(factory setting)
CONFIGURATION
ALARM OUTPUT
DE-ENERGIZED / PC
AT ALARM
ENERGIZED
!
!
!
!