Omron CVM1-CLK21, CS1W-RPT01 Message Delay Times, 1 CS/CJ-series, CVM1, and CV-series PLCs

Message Delay Times Section 8-4

In this case, the data processing time required for data exchange and the data transmission time are not negligible and need to be included in the calcula- tion. Each time can be determined as follows.

Data Processing Time (see page 254.)

0.0025 ⋅ (8 + 16) ⋅ 8 + 4.7 = 5.18 ≅ 5.2 ms

Data Transmission Time

Data transmission time varies with the baud rate.

Baud rate	Data transmission time
2 Mbps	Number of data link words ⋅	0.008 ms
1 Mbps	Number of data link words ⋅	0.016 ms
500 Kbps	Number of data link words ⋅	0.032 ms

In this example, the number of data link words is (8 + 16) ⋅ 8 = 192, so the data transmission time can be determined as follows:

0.008 ⋅ (8 + 16) ⋅ 8 = 1.536 ≅ 1.5 ms

Assume that the sum of the instruction execution time and I/O refresh time for the PLCs at nodes #1 and #7 is 1 ms. The equation for minimum data link I/O response time is as follows:

Input ON delay	---
Instruction execution time + I/O refresh	1 ms
time for PLC at node #1
Data processing time	5.2 ms
Data link transmission time	1.5 ms
Data processing time	5.2 ms
Instruction execution time + I/O refresh	1 ms
time for PLC at node #7
Output ON delay	---
Total (data link I/O response time)	13.9 ms

Noise may increase I/O delays.

8-4	Message Delay Times
	The two charts which follow indicate the sequence of processing which will
	enable users to calculate the maximum delay time to be expected between
	the time SEND(192) or RECV(193) is executed and the time the data is stored
	in the destination or source node’s memory area, ready for use by other
	instructions in the program.
8-4-1 CS/CJ-series, CVM1, and CV-series PLCs
SEND	The following diagram indicates the data flow which will yield the maximum
	delay time from the time SEND(192)/SEND(90) is executed by the user pro-
	gram to the time the Controller Link Unit stores the data in the destination
	Unit’s memory.

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