Rotex Controller Series User Manual

EbV Product documentation THETA NORM/UNIT
10-3
Changeover basic
load in group
formation: Wenn the group is formed by parameterization and the peak load boiler(s) are
activated, the leading groups can be switched via a parameter. If this parameter is
on ON, the group of peak load boilers, on demand, takes over the basic load and the
basic load boilers take over the correction of the flow temperature. The stage switch-
over is still only active for the actual basic load boilers.
10.3 Mode of operation of cascade control
10.3.1 Switch-on characteristics
The switch-on characteristics of the boiler stages is determined by the set switching
differential and the dynamic switch-on delay. The stage number is incremented only
when the following criteria are fulfilled.
BT
ACT
< BT
NOM
- SD/2
t >= t
switch-on delay
* (100 - (dFT * 100 / FTnom) ) / 100
The boiler temperature of the leading boiler or the common flow sensor has to have
been below the set boiler temperature minus half the switching differential, at least
as long as the calculated switch-on delay.
The switch-on delay is reduced if the actual temperature decreases far below the
switching differential. The reduction is proportional to the ratio
dFT = Difference nominal flow temperature and actual flow
temperature
FT
nom
= nominal flow value
SD
cascade
= 1/2 cascade switching differential
Operation:
Note on operation Key / parameter tree Parameter
Switching differential CASCADING. PARAMETER 01
Switching on delay CASCADING PARAMETER 02
Switching off delay CASCADING PARAMETER 03
Sequential switch-over powerstage
sequence
CASCADING PARAMETER 04
Reverse boiler sequence CASCADING PARAMETER 05
Leading stage CASCADING PARAMETER 06
Peak load boiler from address CASCADING PARAMETER 07
Changeover basis power at group
formation
CASCADING PARAMETER 08
dFT - SD
cascade
/ 2
FT
nom
- SD
cascade
/ 2

Rotex Controller Series Specifications

General

Brand	Rotex
Model	Controller Series
Category	Controller
Language	English