Cascade Control - REMEHA SCB-10 Betriebs Und Installationsanleitung

3.3

Cascade control

Fig.6 Cascade numbering
A
Fig.7 Traditional cascade control
management
4
+3K
-3K
3
2
1
0 4 8
T T
Fig.8 Parallel cascade control
management
2
+3K
-3K
1
0 4 8
T T
7747028 - v.01 - 25112019
Tab.6
Input signal (V)
0–2.0
2.0–2.2
2.0–10
With the HMI T-control mounted in the master boiler it is possible to
manage up to 7 boilers equipped with the HMI S-control in cascade. The
system sensor is connected to the master boiler. All the boilers in the
cascade are connected by an S-BUS cable. The boilers are automatically
numbered:
B C
There are two options for cascade control management:
Adding supplementary boilers successively (traditional control).
Adding supplementary boilers simultaneously (parallel control).
The cascade control management can be changed with parameter NP006.
AD-3000964-01
5
6
x 4 8
T T
AD-3000960-02
3
4
Temperature type cascade algorithm; the setpoint sent to the running
boiler is:
Output; requested by the zones.
Temperature; output setpoint requested by the zones + error calculation.
x 4 8
T T
AD-3000961-02
Output type cascade algorithm; the setpoint sent to the running boiler is:
Output; according to PI algorithms.
Temperature; -90°C
The type of cascade algorithm can be changed with parameter NP011.
Control based on heat output
Heat output (%)
0
0
0–100
A The master boiler is number 1.
B The first slave boiler is number 3 (number 2 does not exist).
C The second slave boiler is number 4; and so on.
1 First boiler starts running when system temperature is 3°C below
set point.
2 After 4 minutes the second boiler starts running if ΔT< 6K and the
system temperature is still more than 3°C below set point.
3 After 8 minutes the third boiler starts running if ΔT< 6K and the
system temperature is still more than 3°C below set point.
4 First boiler stops running when system temperature is 3°C above
set point.
5 After 4 minutes the second boiler stops running if ΔT< 6K and the
system temperature is still more than 3°C above set point.
6 After 8 minutes the third boiler stops running if ΔT< 6K and the
system temperature is still more than 3°C above set point.
T Duration between start and stop of boilers can be changed with
parameter NP009.
1 All boilers in cascade start running when system temperature is
3°C below set point.
2 First boiler stops running when system temperature is 3°C above
set point.
3 After 4 minutes the second boiler stops running if ΔT< 6K and the
system temperature is still more than 3°C above set point.
4 After 8 minutes the third boiler stops running if ΔT< 6K and the
system temperature is still more than 3°C above set point.
T Duration between start and stop of boilers can be changed with
parameter NP009.
en
3 Before installation
Description
Boiler off
Heat demand
Desired heat output
9