On-Demand Function Specification Method And Specification Examples - Mitsubishi Electric FX3U-232-BD User Manual

FX Series PLC User's Manual - Data Communication Edition
Computer Link

7.13.3 On-demand function specification method and specification examples

This subsection explains the on-demand function specification method and specification examples.
When using ch2 in an FX
special data registers (D) according to the table below.
All PLCs except FX
FX , FX
3G 3GC
*1. FX , FX
0N
1. Specification method
The specification method in the control procedure format 1 is shown below:
Computer side
PLC side
On-demand send processing
M8127
PLC
1) Specify the data quantity specification range while satisfying the following condition:
- Amount of data  40H (= 64 in decimal)
2) The PLC adds "FE" as the PLC number.
3) Express the station number, PLC number, number of device points and sum check code in hexadecimal.
IMPORTANT
Do not use the on-demand function when the system configuration is not 1-to-1 type.
If the on-demand function is used in the multi-drop link system in which the computer and PLC CPUs have
the 1-to-N configuration, the transfer data and on-demand send data in the control procedure format 1 or 4
are destroyed, and normal data sending is not possible.
D-82
, FX , FX
3G 3GC
, FX , FX and FX
3G 3GC 3U 3UC
, FX and FX PLCs (ch1)
3U 3UC
*1
M8127
M8128
M8129
D8127
D8128
, FX and FX PLCs do not support this device.
1S 1N 1NC
Writes data to be sent and
amount of data to be sent.
or FX Series PLC, exchange special auxiliary relays (M) and
3U 3UC
PLCs
FX , FX
3G

Added by PLC
S
Data to be
T
sent
X
ON
Write the head device number (data register)
storing the data to be sent to the special data
register D8127.
Write the amount of data to the special data
register D8218.
7.13 On-demand Function
, FX and FX PLCs (ch2)
3GC 3U 3UC
M8427
M8428
M8429
D8427
D8428
E
T
X
OFF
7 Commands