Read command delay time – Omron CS CJ1W-ETN21 User Manual

Page 217

Advertising
background image

193

Maximum Transmission Delays: Writing/Reading to CPU Unit

Section 7-5

For details, refer to the CPU Unit operation manual.

Transmission Processing
(Response)

0.704 ms

Note

The actual operating environment can cause transmission delays larger than
those calculated with the methods given here. Among the causes of longer
delays are the following: traffic on the network, window sizes at network
nodes, traffic through the Ethernet Unit (e.g., simultaneous socket servicing
and FTP server communications, etc.), and the system configuration.

Read Command Delay
Time

Maximum transmission delay =

Transmission processing time (remote node)
+ Transmission delays
+ Reception processing time (command) (local node)
+ CPU Bus Unit service cycle (local node)
+ CPU Bus Unit service processing time (local node)
+ Transmission processing time (response) (local node)
+ Transmission delays
+ Reception processing time (remote node)

Transmission Delay

The transmission delay time depends on the baud rate set for the Ethernet
Unit, as shown in the following table. (Additional delays may depending on
devices, such as hubs, in the network configuration.)

Reception Processing
(Command)

0.704 ms

CPU Bus Unit Service
Cycle

The processing time will be as follows, depending on the CPU processing
mode settings at the CPU Unit.

Parallel processing with
synchronous memory
access

Set time for peripheral servicing

(Default: 4% of CPU Unit cycle time)

Parallel processing with
asynchronous memory
access

1 ms max.

CPU execution mode

Processing time considerations

Baud rate

Delay time

100Base-TX

Command

0.0118 ms

Response

Number of words sent

×

0.0013 + 0.0118 ms

10Base-T

Command

0.0157 ms

Response

Number of words sent

×

0.0019 + 0.0157 ms

CPU execution mode

Processing time considerations

Normal Mode

CPU Unit cycle time

Priority peripheral ser-
vicing

Ethernet Unit is given prior-
ity.

Time slice instruction execu-
tion time

Ethernet Unit is not given
priority.

CPU Unit cycle time

Parallel processing with
synchronous memory
access

CPU Unit cycle time

Parallel processing with
asynchronous memory
access

0.2 ms + peripheral servicing time (1 ms max. of peripheral
servicing time for each Special I/O Unit, CPU Bus Unit,
peripheral port, RS-232C port, and Inner Board)

Advertising