Devicenet Communications Response Time; One Master In Network; Communications Time For 1 Slave - Omron 3G3MV-PDRT2 User Manual

Appendices

10-3 DeviceNet Communications Response Time

This section describes communications response time when OMRON Master and Slave Units are
being 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 exam-
ple).
Communications Cycle Time
■
●

One Master in Network

The following equations show the communications cycle time (TRM) when there is only one Master
in the network. If the calculation result is less than 2 ms, the communications cycle time (TRM) will
be considered as 2 ms.
= Σ Communications time for 1 Slave
T
RM
+ High-density Unit processing time
+ Explicit message processing time
+ COS/Cyclic connection communications time
+ 0.01 × N + 1.0 (ms)
Note N = Number of Slaves.

Communications Time for 1 Slave

This is the time required for 1 Slave to perform communications. " Σ Communications time for 1 Slave"
in the above equation represents the sum of the communications times for each Slave in the network.
The equations used to calculate the communications time (TRS) for different types of Slave are given
below.
Output Slaves with 8 or Less Bytes of Output
0.016 × T
T =
RT B
S : The number of Output Slave output words
OUT1
T : The baud rate factor
B
(500 kbps: T
Input Slaves with 8 or Less Bytes of Input
0.016 × T
T =
RT B
S : The number of Input Slave input words
IN1
T : The baud rate factor
B
(500 kbps: T
× S + 0.11 × T
+ 0.07 (ms)
OUT1 B
= 2; 250 kbps: T
B
× S + 0.06 × T
+ 0.05 (ms)
IN1 B
= 2; 250 kbps: T
B
= 4; 125 kbps: T = 8)
B B
= 4; 125 kbps: T = 8)
B B
Chapter 10
10-27