Omron CS1W-MCH71 Operation Manual page 710

Performance
• The ratio between the Unit cycle and communications cycle is adjusted.
Calculation Method for Unit Cycle
Basic formula for calculating Unit Cycle is shown below:
Unit Cycle [ µ s] = (85 × No. of axes) + (120 × No. of motion tasks × No. of parallel branches) + (0.3 × No. of gen-
eral allocated words) + 200 --- (1)
• No. of axes: No. of axes allocated in [P1AA01:Physical axis setting] (Sum of virtual and actual axes)
• No. of Motion tasks: P00001 [No. of Motion tasks]
• No. of parallel branches: P00002 [No. of parallel branches]
• No. of general allocated words: No. of Allocated words to be used as general purpose I/O (Sum of inputs
Note for P00003 [Unit Scan time]
When P00003 [Unit Scan time] is greater than the result of the formula (1), the formula (2) below is to be used.
Unit Cycle [ µ s] = P00003 × 1000 ---(2)
Determining Unit Cycle
The Unit Cycle can be determined by rounding up the Unit Cycle [ µ s] that was found using formula (1) or (2) to
1 ms, 2 ms, 3 ms, 4 ms, 6 ms, or 8 ms.
If the unit cycle time exceeds 8 ms, 8 ms is set.
Calculation Method for Communications Cycle
Basic formula for calculating Communications Cycle is shown below:
Communications Cycle [ µ s] = ((No. of allocated nodes + No. of Retries) × 102.7 + 19.2) × 1.1 ---(3)
• No. of Allocated Node: No. of MECHATROLINK-II slaves (only physical axes) allocated in [P1AA01: Phys-
• No. of Retries: No. of retries specified in [P00009: MECHATROLINK No. of retrial nodes setting] (= 0-7).
If the Communications cycle was less than 1ms, the formula (4) below is to be used.
Communications cycle [ µ s] = 1000 ---(4)
Determining Communications Cycle
The Communications Cycle can be determined by rounding up the Communications Cycle [ µ s] that was found
by the formula (3) or (4) to 1 ms, 2 ms, 3 ms, or 4 ms.
If the communications cycle time exceeds 4 ms, 4 ms is set.
Note The formula used in this section applies when P00004 bit 09 is 1 for a CJ1W-MCH71 or CS1W-MCH71
Motion Control Unit with unit version 3.0 or later. If the unit version is 2.0 or earlier, or the unit version is
3.0 or later but P00004 bit 09 is 0, the following formula applies.
Unit cycle [ µ s] = (115.0 × Number of axes) + (165.0 × Number of motion tasks × Number of parallel
branches) + (0.3 × Number of general allocated words) + 350.0Communications cycle [ µ s] = ((No. of
allocated nodes + No. of Retries) × 133.3 + 26.2) × 1.1
Adjusting the Unit Cycle and Communications Cycle
Determine the combination of the Unit Cycle and Communications Cycle using the following table:
Communica-
tions cycle
1 ms
1 ms 1 ms: 1 ms
2 ms 2 ms: 2 ms
and outputs)
ical Axis Setting]
2 ms
2 ms: 1 ms 3 ms: 3 ms
2 ms: 2 ms 3 ms: 3 ms
Unit cycle
3 ms *1
4 ms
4 ms: 2 ms
4 ms: 2 ms
Appendix A
6 ms 8 ms
6 ms: 3 ms 8 ms: 4 ms
6 ms: 3 ms 8 ms: 4 ms
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