Mitsubishi Electric Melsec Q Series User Manual page 252

7
PROGRAMMING
(5) Program example
7
- 63 7.8 Program Example When Mounting the QJ71PB92V on a MELSECNET/H Remote I/O Network
7.8.1 Program example for the I/O data exchange function (When mounted on a remote I/O station)
(a) Interlock program example for remote master station and remote I/O station
Provide interlocks depending on the link status of the remote master station (host
station) and remote I/O station (other station).
The following example shows a communication program interlock using the link
status (SB47, SB49) of the remote master station and the link status (SW70 b0,
SW74 b0, SW78 b0) of the remote I/O station (station No. 1).
I/O data exchange program (
Figure 7.24 MELSECNET/H Remote I/O Network Interlock Program Example
Set an appropriate value for the timer constant K
Item
Baton pass status
(T0, T2)
Cyclic transmission status
Parameter communication
status
(T1, T3, T4)
* 1 To prevent control from stopping even if the network detects an instantaneous error due to a cable
problem, noise, etc.
Note that "4" and "3" represent standard values.
POINT
For details of the interlock program for the MELSECNET/H remote master station
and remote I/O station, refer to the Q Corresponding MELSECNET/H Network
System Reference Manual (Remote I/O Network).
(b)
)
Table7.63 Set Value for Timer Constant
(Sequence scan time 4) or more
( Sequence scan time 3) or more
SB47 : Host baton pass status
SB49 : Host data link status
SW70 : Baton pass status
of each station
SW74 : Cyclic transmission status
of each station
SW78 : Parameter communication
status of each station
SB20 : Module status
according to the following.
Set Value