Omron SYSMAC CJ - REFERENCE MANUAL 01-2008 Reference Manual page 984

Basic I/O Unit Instructions
Timing Chart
I
Four digits: 00 to 03
Eight digits: 00 to 03, 04 to 07
O
00
01
02
03
04
05
Flags
Precautions
Example
0 1
10 10
0 1 2 3 4 5 6 7 8
16 cycles to complete one round of execution
Name
Error Flag ER
Do not read or write the system word (C2) from any other instruction.
DSW(210) will not operate correctly if the system word is accessed by another
instruction. The system word is not initialized by DSW(210) in the first cycle
when program execution starts. If DSW(210) is being used from the first cycle,
clear the system word from the program.
DSW(210) will not operate correctly if I/O refreshing is not performed with the
Input Unit and Output Unit connected to the digital switch or thumbwheel
switch after DSW(210) is executed. Consequently, do not connect the digital
switch or thumbwheel switch to the following Units.
• Basic I/O Units or High-density I/O Units mounted in a SYSMAC BUS
Remote I/O Slave Rack
• Communications Slaves (DeviceNet or CompoBus/S Slaves)
In this example, DSW(210) is used to read an 8-digit number from a digital
switch and outputs the resulting value constantly to D00000 and D00001. The
digital switch is connected through CIO 0100 (allocated to a CS1W-ID211 16-
point DC Input Unit) and CIO 0200 (allocated to a CS1W-OD211 16-point
Transistor Output Unit).
Since 8 digits of data are being read, C1 (D32000 in this case) is set to 0001
hex. D32001 is used as the system word.
2 3
10 10
9 10 11 12 13 14 15 16
Label
OFF
P_On
Always ON Flag
Section 3-23
Input data
Leftmost Rightmost
4 digits 4 digits
D+1 D
When only 4 digits are read,
only word D is used.
CS signals
RD (read) signal
One Round Flag
Operation
DSW(210)
I 0100
0200
O
D00000
D
D32000
C1
D32001
C2
945