Cyclic changeover of heat generators within a group

The cyclic changeover will balance the runtimes of the connected heat generators.

The cyclic changeover uses an internal communication signal which will be automatically connected.


ATTENTION:

When a heat generator’s position number is in the cyclic changeover range, it shall have a minimum runtime SYS-04 different of „0“.

If the heat generator runtime is set to the value “0”, it will decrease its position number during every cyclic changeover and finally reach the first position and stay there.


Each heat generator has a position number, defined by parameter SYS-01, which is used for cyclic changeover. When a heat generator exceeds its maximum runtime, defined by parameter SYS-04, this module starts a procedure to become the last heat generator in the group. All the following heat generators will automatically decrease their position number by one.


ATTENTION:

The cyclic changeover occurs immediately when the hours run are exceeded if one of the following conditions are true:

If the cyclic changeover conditions are not fullfiiled till 1:00 o’clock:


Example: Cyclic changeover

For three boilers in the cyclic changeover, set the changeover sequence of the strategy CYC-01 to 0103 (numbers 1 and 3).


Initial situation

Heat generator

Position number

Max hours run
SY-04 of boiler

Actual hours run

Boiler A

1

200

90

Boiler B

2

100

70

Boiler C

3

150

30

Boiler D

4

Does not care

Does not care


After 30 hours boiler B reaches its maximum hours run assuming that all 3 boilers being switched on during that time.

Boiler B will initialize the cyclic changeover:


After 30 hours before cyclic changeover:

Heat generator

Position number

Max hours run
SY-04 of boiler

Actual hours run

Action

Boiler A

1

200

120

None

Boiler B

2

100

100

position number to end of sequence; reset hours run

Boiler C

3

150

60

decrement position number by one

Boiler D

4

does not care

does not care



After 30 hours after cyclic changeover:

Heat generator

Position number

Max hours run
SY-04 of boiler

Actual hours run

Boiler A

1

200

120

Boiler B

3

100

0

Boiler C

2

150

60

Boiler D

4

does not care

does not care


Table 18.   Parameter List

Description

Value Range

Default Value

Unit

SYS-01: position number

1...16

1

-

SYS-04: maximum boiler runtime

0...1E6

100

h