Maximum Transmission Delays: Writing/Reading to CPU Unit | Section | ||
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| CPU execution mode | Processing time considerations | |
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| Parallel processing with | Set time for peripheral servicing |
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| synchronous memory | (Default: 4% of CPU Unit cycle time) |
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| access |
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| Parallel processing with | 1 ms max. |
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| asynchronous memory |
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| access |
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| For details, refer to the CPU Unit operation manual. |
Transmission Processing | 0.704 ms |
(Response) |
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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
Transmission Delay
Reception Processing (Command)
CPU Bus Unit Service Cycle
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)
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.)
Baud rate |
| Delay time |
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Command | 0.0118 ms | |
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| Response | Number of words sent ⋅ 0.0013 + 0.0118 ms |
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Command | 0.0157 ms | |
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| Response | Number of words sent ⋅ 0.0019 + 0.0157 ms |
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0.704 ms
The processing time will be as follows, depending on the CPU processing mode settings at the CPU Unit.
CPU execution mode | Processing time considerations | |
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Normal Mode | CPU Unit cycle time |
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Priority peripheral ser- | Ethernet Unit is given prior- | Time slice instruction execu- |
vicing | ity. | tion time |
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| Ethernet Unit is not given | CPU Unit cycle time |
| priority. |
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Parallel processing with | CPU Unit cycle time |
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synchronous memory |
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access |
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Parallel processing with | 0.2 ms + peripheral servicing time (1 ms max. of peripheral | |
asynchronous memory | servicing time for each Special I/O Unit, CPU Bus Unit, | |
access | peripheral port, | |
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