Pc Link System I/O Response Time - Omron SYSMAC CVM1 Series Operation Manual

Calculating the PC Link Transmission Time
Calculating the PC Link Cycle Time
The following diagram shows the PC Link's cycle time.
T
N
Polling Unit
(Master)
Send
Slave
Node 1
Polling
PC Link cycle time = (T
N
T = Transmission time/Node
N
Number of Link bits/Unit
T (ms)
N
Example Calculation:
When there are 128 Link Relay bits/Unit and 8 Units are connected, T
PC Link cycle time = 2.8 × 8 + 10 ms = 32.4 ms
Calculating the Polling Sequence Processing Time
The link polling sequence, which is directed to nodes that have not yet joined the PC Link, is sent once every
256 PC Link cycles. Consequently the polling sequence cycle is 256 × one PC Link cycle.
PC Link
cycle
256 PC Link cycles
Polling
sequence
processing
Polling sequence processing time = 15 ms × (n − m)
(n: max. number of connectable Units; m: number of Units joined into PC Link)
Minimum Transmission Time
Minimum transmission time = T
To determine the value of T
Appendix C

PC Link System I/O Response Time

One cycle's transmission time
Receive
Node 2
Processing time when data
Slave data transfer
transfer is completed = 10 ms
× Total number of PLCs in PC Link) + 10 ms
32 64 128
2.2 2.5 2.8
Polling
sequence
processing
+ 10 ms
N
, refer to the table above.
N
10 ms
Processing
Node n
256 512
3.8 5.8
= 2.8 ms.
N
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