Omron CJ1W-FLN22, Руководство по эксплуатации, Страница: 163 / 277

137
Message Service Transmission Delays Section 8-5
8-5 Message Service Transmission Delays
The conceivable criteria are provided here for determining the maximum
transmission delay time from the time the SEND(090)/RECV(098) instructions
are executed from the user program until execution is completed. Use the fol-
lowing equation to calculate the maximum transmission delay times. These
times, however, do not take transmission delay times on the network into
account, so they may be increased depending on the conditions under which
the instructions are executed.
Send
The transmission delay for the SEND(090) instruction can be calculated using
the following equation:
Transmission delay = Local node service cycle + local node service process-
ing time + communications cycle time + token holding time + remote node ser-
vice cycle + remote node service processing time
• CPU Bus Unit Service Cycle
One scan of CPU Unit.
• CPU Bus Unit Service Processing Time
CPU Unit peripheral processing: This is the time required to process
CPU Bus Units and is approximately 1 ms for FL-net Units.
• Communications Cycle Time
Time taken by the token to do one rotation.
Note 1. 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, traffic through the
FL-net Unit, as well as the parameters and system configuration of the FL-
net network.
2. The CPU data set processing time is the standard when the peripheral ser-
vice time is set in the CPU Unit System Setup to the default of 4%. As this
value is increased, the processing time is shortened.
SEND(090) instructions
executed from user
program
CPU Bus Unit Service
Processing (local node)
CPU Bus Unit Service
Cycle (local node)
Communications
Cycle Time
CPU Bus Unit Service Cycle (remote node)
CPU Bus Unit Service Processing (remote node)
Max. delay