ICP DAS USA ISaGRAF WinCE ViewPAC, User Manual

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ISaGRAF WinCE ViewPAC User Manual , V.1.6 , 1/2017 by ICP DAS
Ap-26
Appendix F Slow Down ISaGRAF Driver’s Speed
You may wonder Why ? The faster speed is not good ?
The reason to slow down the speed of ISaGRAF driver is when you running some other HMI program
(For example, InduSoft, VB.NET or C#.NET program) with ISaGRAF at the same time. Because the CPU is
the only one CPU, all program running in ViewPAC must share execution time of the same CPU. If you
feel the HMI program behavior is not so smooth, or slow, you may use ISaGRAF function – “PLC_Mode( )”
to slow down the speed of the ISaGRAF driver.
PLC_Mode
Argument:
MODE_ integer Can be 0 , 1, 2, or 3
0: Fast Mode, Default setting, the minimum PLC scan time is about 2 ~ 3 ms
1: Slow Mode, the minimum PLC scan time is about 6 to 7 ms
2: Slower Mode, the minimum PLC scan time is about 9 to 11 ms
3: or other value: Slowest Mode, the min. PLC scan time is about 19 ~ 21 ms
Return:
Q_ Boolean always return True
Note
:
1. The system's default setting is "Fast Mode"
2. User may call "PLC_mode( )" in the first PLC scan to change the PLC speed.
3. The reason to slow down the PLC speed is to improve the speed performance of other HMI program
running with ISaGRAF driver at the same time. For example, running InduSoft with ISaGRAF in the
same ViewPAC.
Example :
(* TMP is declared as Boolean internal variable *)
(* INIT is declared as Boolean internal variable and init at TRUE *)
if INIT then
INIT := False ; (* Only do it once in the 1st PLC scan *)
TMP := PLC_mode(2) ; (* Set PLC speed to 2:slower mode *)
end_if ;
Description:
Function Change the ISaGRAF driver speed