Directsoft, storing max # in register

Hi, does anyone know if its possible to watch an analog input (4-20 ma)and store the maximum amount in a reg to output to a display?
For example: A distance proximity switch is used to measure a product distance, yet the distance keeps varying, I want the maximum distance achieved in a period (using a counter, not timer) sent to a register and stored.
Any ideas?

Thanks.. Shane
PLC Direct 305 / 340 CPU
Directsoft v1.1

Just keep updating a register as long as it continues to increase...

| "ANALOG"   Vnnnn

|---------]>[----------+---[LD "ANALOG"]

|                      |

|                      +---[OUT Vnnnn]

.
Vnnn will contain the highest value achieved.

Remember, you'll have to clear the Vnnnn value at the start of your sample time.

Why do you have to do it "using a counter, not timer"???

They're basically the same thing... Or, is that what your teacher asked for?...

beerchug

-Eric

More

Hi, Im working on a ski lift.
We measure every thing in distance (pulses/revolution of a wheel) so nothing changes as the ski lift runs at 100 feet per minute vs. 1000 feet per minute.
Problem is, if we stop the lift, there is slack in the cable which causes the haul cable and chair to sort of oscillate back and forth as the lift comes to a stop. This causes the multiple measurments of the grip force when the chair happens to be below the sensor. I would like to somehow record the highest reading, send it to a register, and then reset with another prox, to get ready for the next chair.
Does this make sense?
The register would then dislay the number.
Then, looking at the register I could stop the lift if the "force" was to little.
(Force=spring pressure)

Thanks...Shane

Your last post is what should have been your FIRST post.

I have given you one idea, so at this point, I'm looking for something more like "Thanks Eric, but your method won't work in my application because..."

beerchug

-Eric

P.S. Wow, 1000 feet/min... Sounds more like a thrill ride than a ski lift!...

Thanks Eric! Actally Im going to try and use your suggestion.
I tryed to "Edit" my original post last night yet I was not able to.
sorry for that
thanks for your help...Shane

If it works, do I get a free lift ticket?...

beerchug

-Eric

Absolutly!
Unfortantly, Im not sure if its the version of Directsoft (2.4) or because Im using a 305 family CPU (340). But it does not support the greater than [>] function as far as I can tell.

The 340 has a COMPARE function, it's just done a little differently.

Attached is a zip file containing a PDF of the 2 pages describing the COMPARE function.
By the way, the whole manual is available HERE.

I use a lot of A-D PLCs, but haven't used any 305 stuff... The manual seems to decribe the instruction's use pretty well, but if you have any difficulty, feel free to ask questions. If I can't help, someone else here will. The DL-305 is the same as a GE Series One and TI-305.

beerchug

-Eric

Back in the days when that product line was known as the GE Series One, you used the 'Compare' function, F70. The function set internal bits 772 for >, 773 for =, or 774 for <. The function compares the accumulator to the specified reference.

It may be too late for this project, but when I'm working with the 300 series on "legacy" systems, I immediately go to the 350 PLC. The programming is the same as the rest of the Koyo line, and it has a lot more features. At $219 it may even be worth your while to change this one, since you can probably save a lot of time on programming.

Thanks all, I'm going to look into all of these suggestions when I return to work on Mon.