Peculiar thing about the Equal instruction

[gbradley]

I had a misconception about how the ACC integer is written.
I've been working on a demo program with a couple of counters counting up and down.
I mistakenly thought that I could make a counter by trapping for some random number in the ACC value and then add 1 to an integer value.
I was using 4000, and my Preset was 5000, so I assumed (Big word) that the ACC value had to go by this number.
The funny thing is, It didn’t always see the ACC value that I was trapping for. About 10% of the time it missed it.
When I think about how the scan time works I guess it makes sense.
I replaced the EQU with a Done bit on the timer, and it works every time.

 

[bernie_carlton]

Exactly. A programmer must always be aware that a scan take time. The programmer must notice any effects that time would have relative to the instructions in the program.

A GEQ with 4000 followed by a one shot would have caught on the first scan when the ACC was at or past 4000. If your timer had a long time base, like one second, the ADD would have fired many times.

 

[gbradley]

There is something else weird about displaying large values in the panelview. PanelView Component (2711C-K3M)
If the value in the Integer location is above 20,000,000 the Panelview display seems to be off, like it won't display odd values.
L9:0 __________ PanelView
20,000,000 >>>> 20,000,000
20,000,001 >>>> 20,000,000
20,000,002 >>>> 20,000,002
20,000,003 >>>> 20,000,004
20,000,004 >>>>20,000,004
20,000,005 >>>>20,000,004
20,000,006 >>>>20,000,006
20,000,007 >>>>20,000,008
20,000,008 >>>>20,000,008
20,000,009 >>>> 20,000,008
My Display is set to 8 digits and the Tag is Real

 

[bernie_carlton]

My Display is set to 8 digits and the Tag is Real

Why would a tage be 'Real' if the source is a 'Long'? That may itself be the problem. You are getting near the upper end of a 32 bit real's being able to hold an increment of just 1. Actually that cutoff is at about 16.7 million.

 

[gbradley]

Why would a tage be 'Real' if the source is a 'Long'? That may itself be the problem. You are getting near the upper end of a 32 bit real's being able to hold an increment of just 1. Actually that cutoff is at about 16.7 million.

I changed the tag to 32 Bit Integer and that fixed it.
Thanks