Message Communications; Message Communications Time - Omron CS1W-DRM21 Operation Manual

Message Communications

Program Example
Slave Function
8-2

Message Communications

8-2-1

Message Communications Time

200
Case
The Master is
started just after
Slave startup.
Just the Master is
restarted.
Just the Slaves are
restarted.
As shown in the preceding table, it takes time for DeviceNet communications
to start up. This programming uses flags in the Master status area to prevents
the Slaves' I/O processing from being performed until remote I/O communica-
tions start up.
This programming is for a DeviceNet Unit with a unit number of 00.
Remote I/O
Communications
(n+12, bit 15)
Note Refer to 3-2 Allocated CIO Area Words for details on the Master Status Area.
It takes approximately four seconds from the time that the Devicenet Unit is
turned ON or restarted as a slave until remote I/O communications with the
master begin.
The message communications time is the time required from the time a Mas-
ter Unit starts to send a message over the Network to another node until the
Master Unit completes sending the message (data for SEND(192)/
RECV(193) and FINS commands for CMND(194)/IOWR).
The following equation can be used to compute the approximate message
communications time.
Message communications time =
Communications cycle time x ((No. of message bytes + 15) ÷ 6 + 1)
No. of message bytes: No. of data bytes following the FINS command code
The communications cycle time depends on whether or not remote I/O com-
munications are being used.
Message Communications Only (No Remote I/O Communications)
The following equation can be used to compute the message communications
time when remote I/O communications are not being used.
Communications cycle time =
2 (see note) + 0.11 × T
Slave's indicator status
The NS indicator is OFF or flashing green.
The NS indicator is flashes red while the Mas-
ter is OFF.
---
1512 1510
15 00
Unit Error
(n+10, bit 00)
+ 0.6 [ms]
B
Section 8-2
System
startup time
5 seconds
7 seconds
9 seconds
Slaves' I/O
processing