Restrictions On Duplex Loop Controllers - Omron SYSMAC CS Series Operation Manual

Duplex Operation of Loop Controllers
3-5-3

Restrictions on Duplex Loop Controllers

Effect on CPU Unit Cycle Times
Effect on CPU Unit Normal
Cycle Times
Effect on CPU Unit Cycle
Time and Loop Controller
Operation Cycle during
Duplex Initialization
Restrictions on Minimum
Operation Cycle for Loop
Controller Function
Blocks
3. Duplex initialization is executed in a cold start. The CS1D system will enter
duplex mode after the duplex initialization has been completed (150 sec-
onds max.)
4. The active Loop Controller's operation cycle will be temporarily lengthened
by 3 seconds max.
The following table shows the time added to the CPU Unit's normal cycle time
by the Loop Controllers in the Process-control CPU Unit.
Loop Controller model
CS1D-CPU@@P
Example of Process-control CPU Unit's Influence on Normal Cycle Time
Function block and user link table opera-
tion cycle (See note (a).)
Number of function blocks
Number of user link tables
Load rate
Influence (ms) by 2-ms cycle time of ladder
program (See note (b).)
Influence (ms) by19-ms cycle time of lad-
der program (See note (b).)
Note (a) The influence of the function block and user link table operation
cycle on the CPU Unit's cycle time is greatest when the function
block and user link table operation cycle is 100 ms.
(b) The influence of the Process-control CPU Unit Loop Controllers
on the CPU Unit's cycle time is greatest when the cycle time of
the CPU Unit is 19 ms.
(c) When sequence tables are used, the extra time in the above table
is further extended. The additional extra time required depends
on how the sequence tables are used, as follows:
• Not expanding sequence tables: +3 ms
• Expanding sequence tables vertically or horizontally: +6 ms
• Expanding sequence tables both vertically and horizontally:
+12 ms
The extended cycle time will not be lengthened if the number of ex-
panded sequence tables increases, but the number of times that
the cycle time is extended will increase.
Refer to page 41.
When using Process-control CPU Unit (CS1D-CPU@@P), it is recommended
that the longest possible operation cycle is set to prevent operation cycle
errors. The operation cycle time for Loop Controller function blocks must be a
minimum of 5 times the CPU normal cycle time (i.e., the cycle time other than
when duplex initialization is being executed).
Time added to normal cycle time
25 ms max.
100 ms
100 150
100 150
39 55
+7.8 +10.5
+10.3 +14.4
Section 3-5
200
200
71
+13.6
+20.8
169