Advanced Function Instruction
7 -5 5
FUN 74
P
IMDIO
IMMIDIATE
I/O
FUN 74
P
IMDIO
D : Starting number of I/O points to be refreshed
N : Number of I/O points to be refreshed
X
Y
K
Range
Ope-
rand
Xn of
Main
Unit.
Yn of
Main
Unit.
1
∣
36
D
○
○
N
○
●
For normal PLC scan cycle, the CPU gets the entire input signals before the program is executed, and then
perform the executing of program based on the fresh input signals. After finished the program execution the
CPU will update all the output signals according to the result of program execution. Only after the complete
scan has been finished will all the output results be transferred all at once to the output. Thus for the input
event to output responses, there will be a delay of at least 1 scan time (maximum of 2 scan time). With this
instruction, the input signals or output signals specified by this instruction can be immediately refresh to get
the faster input to output response without the limitation imposed by the scan method.
●
When refresh control "EN" = 1 or "EN
↑
" (
P
instruction) has a transition from 1 to 0, then the status of N
input points or output points (D~D+N-1) will be refreshed.
●
The I/O points for FBs-PLC's immediate I/O are only limited to I/O points on the main unit. The table below
shows permissible I/O numbers for 20, 32, 40 and 60 point main units:
Main-unit type
Permissible numbers
20 points
32 points
40 points
60 points
Input signals
X0
~
X11 X0
~
X19 X0
~
X23
X0
~
X35
Output signals
Y0
~
Y7 Y0
~
Y11 Y0
~
Y15
Y0
~
Y23
●
If the intended refresh I/O signals of this instruction is beyond the range of I/O points specified on above
table then PLC will be unable to operate and the M1931 error flag will be set to 1. ( for example, if in a
program, D=X11, N=10, which means X11 to X20 are to be immediately retrieved. Supposing the main unit
is FBs-32MA, then its biggest input point is X19, and clearly X20 has already exceeded the main unit's input
point number so under such case M1931 error flag will be set to 1).
●
With this instruction, PLC can immediately refresh input/output signals. However, the delay of the hardware
or the software filter impose on the I/O signals still exist. Please pay attention on this.
Содержание FBs-CBE
Страница 78: ...MEMO ...
Страница 111: ...4 6 X0 X1 Node A Y0 Y1 Node B differential down Incerse differential up t Scan time Inverse t t ...
Страница 141: ...Basic Function Instruction 6 16 FUN 2 SKP SKIP START FUN 2 SKP Y2 Y1 Y0 T201 10S X0 X1 X2 0 10 0 ...
Страница 305: ...MEMO ...
Страница 348: ...MEMO ...