Data Transfer By I/O Instruction ････････････････････28 - Toshiba V Series Operation Manual

Chapter 8 Cyclic Transmission
For data I/O by batch I/O, data synchronicity is guaranteed only up to one word.
8.2 Data Transfer by I/O Instruction
Synchronicity of multiple word data is not guaranteed by batch I/O described in the previous
section. This section describes the data I/O method to guarantee the synchronicity of
multiple word data by using the XMIT_T function block (FB) in the user program without
using the batch I/O function of the S controller. When using this method, "Network Variable
Registration/Assignment" with Engineering Tool is unnecessary.
The I/O operation of this method is as follows:
(1)
8
(2)
(3)
(4)
28
User program issues I/O request to FL312 with XMIT_T-FB.
Cyclic data write request:
Cyclic data read request:
FL312 performs read/write to common memory according to the received instruction.
FL312 performs exclusion control between the cyclic transmission transmit/receive
process and this common memory I/O process.
This exclusion control guarantees the I/O data synchronicity for the transmission path
in transmit/receive units.
When I/O process completes, FL312 returns DONE to the S controller.
The S controller notifies the OS that the requested XMIT_T-FB has completed.
model 3000 FA Control Network [FL-net(OPCN-2)] FL311/FL312 Module Operation Manual
Caution
Data stored in S controller register is written in FL312
common memory.
Data stored in FL312 common memory is loaded into S
controller register.