Omron CJ1W-ETN21 Network Card User Manual


 
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)