Omron EJ1 - 07-2008, Operation Manual

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Remote I/O Communications Characteristics Section 7-1
Maximum I/O Response
Time The maximum I/O response time occurs with the I/O timing shown in the fol-
lowing diagram.
T
IN
: The Input Slave's ON (OFF) delay
T
OUT
: The Output Slave's ON (OFF) delay
T
RM
: The whole Network's communications cycle time
T
PLC
: The PLC's cycle time
T
RF
: The PLC's DeviceNet Unit refresh time
Note Refer to the information on each slave for details on Input and Output Slaves'
ON and OFF delay times. Refer to
7-1-2 CompoWay/F Communications
Cycle Time and Refresh Time and the Operation Manual for the PLC being
used for details on the PLC's cycle time.
The maximum I/O response time (T
MAX
) is the total of the following terms:
T
MAX
= T
IN
+ 2 × T
RM
+ 2 × T
PLC
+ T
RF
+ T
OUT
7-1-2 CompoWay/F Communications Cycle Time and Refresh Time
This section explains the communications cycle time and refresh processing
time required to calculate various processing times for DeviceNet.
Communications
Cycle Time
The communications cycle time is the time from the completion of a slave's
I/O communications processing until I/O communications with the same slave
are processed again. The communications cycle time of the DeviceNet Com-
munications Unit is the maximum CompoWay/F communications cycle time
T
IN
+ T
OUT
.
Reference values for CompoWay/F communications cycle time are given
below.
Communications Cycle
Time Reference Values Total communications cycle time = IN communications cycle time + OUT com-
munications cycle time.
PLC
T
PLC
T
OUT
T
IN
T
RM
T
RF
T
PLC
T
RM
Master Unit
Input
Output
Instruction
execution
Instruction
execution Instruction
execution
No. of Temperature
Controllers
TIN TOUT
1 100 ms 100 ms
8 400 ms 700 ms
16 900 ms 1,200 ms