Lauda RE 1050 G, Operating Instructions Manual

Page: 60 / 101

ECO GOLD
60
Putting the device into operation
28.04.10/ YACE0088
7.9.2 External control variable
Only change the control parameters if you have appropriate knowledge of control techniques.
Continue reading here only if you have connected a temperature sensor or the actual temperature is read
in from a module (and you have activated it as in section 7.7 as a control variable).
The control system for external actual values is realised as a two-stage cascade controller to improve the
response to setpoint changes. From the temperature setpoint and the external temperature, which is gen-
erally measured by the external Pt100, a "master controller" determines the "internal setpoint" which is
passed to the slave controller. Its set value controls the heating and cooling.
Correcting quantity limit
If a step change in set-point temperature is specified, the optimum control might set an outflow tempera-
ture which is substantially higher than the temperature desired on the external vessel. With the correcting
quantity limit the maximum permissible deviation between the temperature on the external load and the
temperature of the outflow liquid can be limited. The limit can be set via a menu point. (
Ì
7.9.2.1)
Description Short form Unit
Gain Kpe -
Proportional range Prop_E K
Reset time
Tne
s
Derivative time Tve s
These parameters can be set on the master
controller (PIDT
1
controller or external con-
troller):
Damping time Tde s
Description Short form Unit
Proportional range Xpf K
These parameters can be set on the slave
controller (P-controller):
If Tv manual/auto is set to "automatic", Tve ,
Tde and Prop_E cannot be changed. Tve
and Tde are in this case derived from Tne
with fixed factors.