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8-11
8-3 CompoBus/D Communications Response Time
This section describes communications response time when OMRON Master and Slave Units are be-
ing used. Use this section for reference when planning I/O timing. The equations provided here are valid
under the following conditions:
• The Master Unit is operating with the scan list enabled.
• All of the required Slaves are participating in communications.
• No errors are being indicated at the Master Unit
• Messages are not being produced in the network (from another company’s configurator, for example).
H Communications Cycle Time
D One Master in Network
The following equations show the communications cycle time (T
RM
) when there is only one Master in
the network. If the calculation result is less than 2 ms, the communications cycle time (T
RM
) will be con-
sidered as 2 ms.
T
RM
= Σ (0.016 × T
B
× S
OUT1
+ 0.11 × T
B
+ 0.07)
+ Σ (0.016 × T
B
× S
IN1
+ 0.06 × T
B
+ 0.05)
+ Σ {0.016 × T
B
× (S
OUT2
+ S
IN2
) + 0.11 × T
B
+ 0.07}
+ 0.11 × T
B
+ 0.65
+ 0.22 × T
B
(number of message nodes)
S
OUT1
: The number of Output Slave output words
S
IN1
: The number of Input Slave input words
S
OUT2
: The number of Mixed I/O Slave output words
S
IN2
: The number of Mixed I/O Slave input words
T
B
: The baud rate factor
(500 kbps: T
B
= 2; 250 kbps: T
B
= 4; 125 kbps: T
B
= 8)
(Varies depending on the baud rate)
D More than One Master in Network
Calculate the communications cycle time according to the above equation for the Slaves of each Master
Unit. The communications cycle time for the entire network is the sum of communications cycle times
for each Master Unit.
Appendices Chapter 8