Baelz Automatic 6490B Device Manual page 20

Page 20
Device manual 6490B / 6490B-y / 6590B
3.15.3 Start up behaviour with delta setpoint dSP
Fig. 2)
Because of the delta setpoint, as soon as the STOP command is inactive, the first OPEN pulse is either
shortened according to the adjusted setpoint lowering and the control deviation Xw, or a CLOSE pulse may
even be given (2).
Example: There is a control deviation of Xw = 15 K. The delta setpoint dSP is adjusted to a setpoint lowering
of -10 K.
As soon as the STOP command is inactive the controller generates only an OPEN pulse according to the
under-temperature of 5 K, instead of an OPEN pulse according to an under-temperature of 15 K.
Example: There is a control deviation of Xw = 10 K. The delta setpoint dSP is adjusted to a setpoint lowering
of -15 K.
As soon as the STOP command is inactive the controller generates a CLOSE pulse according to the
over-temperature of 5 K, instead of an OPEN pulse according to an under-temperature of 10 K.
Because of the high energy input during the ignition stage the temperature can still rise after a possible
CLOSE pulse.
Temperature overshoot is limited by delta setpoint (3). However, its effectiveness depends on the correct
dSP setting like shown in the examples.
W. Bälz & Sohn GmbH & Co. Koepffstraße 5 D-74076 Heilbronn Telefon (07131) 1500-0 Telefax (07131) 1500-21