A - 5 A - 5
4 THE EXCHANGE BETWEEN THE PLC AND BUFFER MEMORY
4-- 1 to 4- 21
4.1 PLC Numeric Data and BASIC Numeric Data ....................................................................................... 4- 1
4.2 The Exchange with the PLC ................................................................................................................... 4- 2
4.2.1 Control tables ................................................................................................................................... 4- 2
4.2.2 PLC station number ......................................................................................................................... 4- 3
4.2.3 Choosing a process ......................................................................................................................... 4-12
4.2.4 Bit/Word designation ........................................................................................................................ 4-12
4.2.5 Device number designation ............................................................................................................. 4-13
4.2.6 Storage area for reading and writing data ....................................................................................... 4-15
4.3 Communication with the Buffer Memory ................................................................................................ 4-20
5 COMMUNICATION USING GENERAL-PURPOSE INPUT/OUTPUT
5- 1 to 5- 7
5.1 Communications Module
PLC CPU (About Input Device X)............................................................ 5- 1
5.2 PLC CPU
Communications Module (About Output Device Y)......................................................... 5- 4
6 I/O PROCESSING OF DATA FILES
6- 1 to 6- 13
6.1 File Numbers ............................................................................................................................................ 6- 2
6.2 Sequential File I/O Procedures................................................................................................................ 6- 3
6.3 Random File I/O Procedures ................................................................................................................... 6- 7
6.4 Caution on Handling Data Files............................................................................................................... 6 12
6.4.1 Handling data files during multitask processing ............................................................................... 6-12
6.4.2 Number of data files that can be handled by each program............................................................ 6-13
7 COMMUNICATION WITH EXTERNAL DEVICES
7- 1 to 7- 14
7.1 Correspondence between the Interface and Channel Number............................................................. 7- 1
7.2 Preparation for the Communication........................................................................................................ 7- 2
7.2.1 Communication parameter setting................................................................................................... 7- 2
7.2.2 Control table ..................................................................................................................................... 7- 4
7.3 Communication Procedure with External Devices................................................................................. 7- 6
7.3.1 Communication with a console ........................................................................................................ 7- 6
7.3.2 Communication with a terminal........................................................................................................ 7- 8
7.3.3 Communicating with a printer .......................................................................................................... 7-10
7.3.4 Communication with other external devices.................................................................................... 7-12
7.4 Interrupt Processing from External Devices........................................................................................... 7-14
8 MULTITASK PROCESSING
8- 1 to 8-19
8.1 Multitask Processing ............................................................................................................................... 8- 1
8.2 How to Synchronize the Execution (Event Control)............................................................................... 8- 5
8.3 To Use Devices (Resources) in Multitasking (Mutual Exclusive Control of Resources) ...................... 8- 8
8.4 Start Another Program from within a Program....................................................................................... 8-13
8.5 Exchanging Data between Tasks........................................................................................................... 8-14
8.5.1 Common memory and internal devices.......................................................................................... 8-14
8.5.2 Message ports................................................................................................................................. 8-16
