Danfoss 5000 Flux, Manual, Page: 17 / 68

VLT ® 5000/5000 Flux/6000 HVAC/8000 AQUA PROFIBUS
MG.90.D1.02 – VLT is a registered Danfoss trademark 17
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SYNC and FREEZE
The control commands SYNC/UNSYNC
(SYNCHRONIZE/CANCEL SYNCHRONIZATION)
and FREEZE/UNFREEZE are broadcast func-
tions. SYNC/UNSYNC is used to transmit synchro-
nized control commands and/or speed reference
values to all connected slave s. F REEZE/UNFREEZE
is used to freeze the status actual value in the
slaves in order to receive a synchronized actual
value from all connected slaves.
The SYNC and FREEZE commands refer to the
PCD and PCV portions of the PPO.
SYNC and FREEZE
SYNC/UNSYNC
By using SYNC/UNSYNC, simultaneous responses
of several slaves can be generated, e.g. synchroni-
zed start, stop, or change of the speed. In the
event of a SYNC command, the current control
word and the speed reference value are frozen. In-
coming process data are saved, but are only ap-
plied when a new SYNC command or an UNSYNC
command is made.
The following example shows the speed reference
value sent by the master in the left column and the
respective effective speed reference value for the
three slaves in the three columns to the right.
Current speed reference value slave
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From DP master to address: Address 3 Address 4 Address 5
1. Speed reference value = 50% to address 3
⇒
50 % 0 % 0 %
2. Speed reference value = 50% to address 4 50 %
⇒
50 % 0 %
3. Speed reference value = 50% to address 5 50 % 50 %
⇒
50 %
4. SYNC command to all addresses
⇒
50 %
⇒
50 %
⇒
50 %
5. Speed reference value = 75% to address 3
⇒
50 % 50 % 50 %
6. Speed reference value = 75% to address 4 50 %
⇒
50 % 50 %
7. Speed reference value = 75% to address 5 50 % 50 %
⇒
50 %
8. SYNC command to all addresses
⇒
75 %
⇒
75 %
⇒
75 %
9. Speed reference value = 100% to address 3
⇒
75 % 75 % 75 %
10. Speed reference value = 50% to address 4 75 %
⇒
75 % 75 %
11. Speed reference value = 25% to address 5 75 % 75 %
⇒
75 %
12. UNSYNC command to all addresses
⇒
100 %
⇒
50 %
⇒
25 %
13. Speed reference = 0% to address 3
⇒
0 % 50 % 25 %
14. Speed reference = 0% to address 4 0 %
⇒
0 % 25 %
15. Speed reference = 0% to address 5 0 % 0 %
⇒
0 %
F R E E Z E / U N F R E E Z E
By using FREEZE/UNFREEZE, simultaneous
reading of process data, e.g. output current, by
several slaves can be brought about. At a FREEZE
command, the actual current values are frozen.
When instructed, the slave will send back the
value in effect at the time the FREEZE command
Actual output current slave
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DP master reads address: Address 3 Address 4 Address 5
1. Address 3 output current = 2 A
⇐
2 A 3 A 4 A
2. Address 4 output current = 5 A 2 A
⇐
5 A 2 A
3. Address 5 output current = 3 A 3 A 2 A
⇐
3 A
4. FREEZE command to all addresses
⇒
1 A
⇒
3 A
⇒
3 A
5. Address 3 output current = 1 A
⇐
4 A 2 A 5 A
6. Address 4 output current = 3 A 2 A
⇐
2 A 2 A
7. Address 5 output current = 3 A 3 A 1 A
⇐
2 A
8. UNFREEZE command to all addresses
⇒
2 A
⇒
3 A
⇒
4 A
Readout same as for 1, 2 and 3
was issued. The respective values are updated
when a new FREEZE command or an UNFREEZE
command is issued.
The following example shows the current values
read by the master in the left column and the
respective effective value of the output current for
the three slaves in the three columns to the right.