Group Function - Mitsubishi Electric SW0DNC-MNETH-B User Manual

12 APPLICATION FUNCTIONS

12.3.3 Group function

CAUTION
12 - 21
The group function is used to group the target stations of a transient transmission and
send data to all of the stations in a group with a single instruction. One network may
have a maximum of 32 groups.
By setting a group designation to the target station number in the control data of a
dedicated instruction, stations with the matching group number retrieve the transient
data.
Note that whether or not the transient transmission is normally completed cannot be
verified because the data are transmitted to multiple stations.
(1) Visual representation of the function
The following figure shows an example of grouping. When a transient
transmission is executed by designating group No. 1, all of the three stations,
1N 3, 1N 5 and 1N
S S
1M 1
P
1N 6
S
Group No. 1
(2) Setting method
Set the group number of the MELSECNET/H board using the "Board information"
screen of the MNETH utility.
Setting range : 1 to 32 (Default : 0 (no group designation))
Set the desired group number.
(3) Transient transmission instructions that allows group designation
Use mdSend to execute the transient transmission instruction in the user
program.
[Precautions when executing the transient transmission by a group function]
When a group is designated, the execution of the transient transmission cannot be
verified.
When this mode of transient transmission is executed successively, a "no reception
buffer space error" (error code: F222) may occur. Design the system thoroughly to
allow for a sufficient interval between executions, and make sure to test (debug) to
confirm that successive executions can be performed without generating any error.
6, retrieve the transient data.
S
1N 2
S
1N 5
S
Group No. 1
MELSEC
Group No. 1
1N 3
S
1N 4
S
12 - 21