Operating instructions

If the proportional range is selected too small, the P part on the
control value is at
100 % for a very long time. This value then
reduces more quickly within the proportional range, i.e. the control
value reduces rapidly and the approach of the actual value to the
setpoint almost comes to a standstill. Due to the I part not
becoming effective until now, the actual value approaches the set-
point slowly.
In this case shown in the graph, the I part is set too large (param-
eter Tn too small). The I part integrates the control deviation until
this becomes 0. If this integration runs too quickly, the control
value, i.e. the output signal of the controller, is too large. This
results in (diminishing) oscillations of the actual value around the
setpoint. Parameter Tv should be adjusted again using the formula:
Tv = Tn x 0.75.
The actual value increases relatively steeply after specification of
the setpoint. The proportional range appears to be well-adjusted.
The approach to the setpoint becomes significantly slower for
diminishing control deviation. The strong reduction of the propor-
tional part (P part) must be compensated for by the integration part
(I part). In this case, the I part integrates too slowly. The parameter
Tn which specifies the integration interval must be reduced. The
lead time (parameter Tv) should also be adjusted using the fol-
lowing formula: Tv = Tn x 0.75.
6.10.2 Calling the control menu
Personnel:

Operating personnel
1. Change to the main menu.
2.
Select the menu item Setup  Control.
Fig. 35: Control parameter Xp too
small
Fig. 36: Control parameters Tn and Tv
too small
Fig. 37: Control parameters Tn and Tv
too large
Operation
Variocool 51