Cyclic Changeover

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

The cyclic changeover sequence (a 4 digit number) can be defined with the parameter CYC-01. The first two (thousands and hundreds) define the start position and the last two digits the stop position number for cyclic changeover.

E.g. 0204 mean that the cyclic changeover happens between the heat generators with position numbers 2 and 4. Position 1 is the leading boiler which will always stay on position number 1, regardless of the setting of its maximum runtime.

If the total number of heat generators in the group is higher than the maximum number of the sequence, the last heat generators will not be cycled considering that they are redundant.


ATTENTION:

When a heat generator’s position number is in the cyclic changeover range, it shall have a minimum runtime (see heat generators SYS-04 maximum boiler runtime) 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.


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

CYC-01 = 0103 – cycle between position numbers 1 and 3.

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 12.   Parameter List

Description

Value Range

Default Value

Unit

CYC-01: cyclic changeover sequence; e.g. 0203 means that boilers 2 to 3 will perform cyclic changeover.

1516

0116