G:\technik\Doku\Doku10\107199\107199Englisch\II.2 Operating instruction.doc / 1/18/2011 12:52 PM /Rg Page 41 of 79
7.5.1.2 What must be considered prior to programming?
A defined start-value must always be entered as the first program line, consisting of temperature
/humidity and runtime t = 0. It can thereby be guaranteed that the guidance will not assume the final
value of the previous assessment.
Should a linear temperature / humidity change not be absolutely necessary, it is more useful to pro-
gram this as a jump (i.e. temperature / humidity set a time t = 0), since the maximum change rate of
temperature or humidity will then be utilized to the full. If a linear change nevertheless becomes nec-
essary, a few points are to be considered:
- It must be confirmed that, during the programming process, the maximum temperature change
rate has not been exceeded.
- If temperature and humidity are simultaneously regulated with linear changes, one can only
achieve a minimal rate of change (max. 0.3 K/min), as compared to when the humidity is turned
off prior to the linear change, since differentiated temperature control procedures have to be util-
ized. Therefore, it should be checked whether a simultaneous linear change at that large capac-
ity is really necessary.
- The regulation of humidity is only possible within a certain temperature-range. If this tempera-
ture-range is either exceeded or not achieved, humidity can only be regulated up to the point of
going over the limit, then no longer. Should there be a temperature change required, however,
from a non-sustainable climate-control range back into the sustainable climate control range,
then there can be, if necessary, a linear regulation of the humidity upon re-entry into the normal
temperature range can be effected. It is basically valid
that: under-achievement or over-
achievement of the normal target temperature values results in the humidity regulation being
turned off. A possibly pre-set humidity target value will be ignored. The actual value of the hu-
midity assumes, however, desired unregulated values, since a relative humidity exists for every
temperature.
The ideal, programmed execution of an assessment program cannot, particularly for jumps within the
temperature / humidity curve, be exactly maintained. The following should be noted:
- A considerable and sudden change in temperature and humidity can be dealt with by the unit
much quicker than a gradual linear change. Since the change cannot take place at a desired
rate, it is better to use the wait-function in this case. It guarantees a secure runtime of stability at
a required temperature and/or humidity niveau.
- Also for a linear change in the temperature or humidity, this can be the case, even though the
maximum rate of change is not exceeded. This is particularly the case, when an adjustment in
the unit has to take place close to the temperature / humidity limits. The closer that a tempera-
ture / humidity pair is situated to these limitations, the slower that the actual process approaches
the target process in curve. Irrespective of the assessment procedure, a slow linear change in
temperature is, however, often times required. In this case as well, the wait-function also guar-
antees a necessary duration of time at the niveau to be achieved.