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Omron CQM1H-CLK21 User Manual

Page 295

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272

Message Delay Times

Section 8-4

interval (destination node) + Transmission processing (response) + Communi-
cations cycle + Transmission delay (response) + Reception processing
(response) + Link Unit servicing interval (source node).

Link Servicing Interval (Source and Destination Nodes)

Link service processing is the same as the PLC’s peripheral servicing and is
approximately 1 ms for Controller Link Units.

Transmission Processing

Commands: 2 ms
Responses: Number of words transferred

×

0.00125 ms + 3 ms

Communications Cycle Time (with Data Links Inactive)

See 8-2 Communications Cycle Time (on page 251).

Transmission Delay Time

Transmission delay time varies with the baud rate.

Note Commands: Transmission delay time is calculated assuming that the number

of words to be transferred is zero.
Responses: Transmission delay time is calculated according to the number of
words to be transferred.

Reception Processing

Commands: 2.3 ms
Responses:

Number of words transferred

×

0.00125 ms + 2.3 ms

The I/O response time might increase due to noise or restrictions on the num-
ber of frames that can be transmitted while the data link is operating.

Example

In this example, the maximum transmission delay is calculated for an instruc-
tion receiving 256 words of data in a system with 32 nodes. Network specifics
are detailed below:

Baud rate:

2 Mbps

Max. node number:

32

Number of nodes:

32

Number of polled nodes: 4
Number of words:

256

Data links:

Halted

Baud rate

Transmission delay time

2 Mbps

Number of words transferred

×

0.008 + 0.112 ms

1 Mbps

Number of words transferred

×

0.016 + 0.224 ms

500 Kbps

Number of words transferred

×

0.032 + 0.448 ms

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