Analog in RSLogix?

stasis · Mar 4, 2005

as stated before, I'm new to this stuff,so, ...how do I set the values/functions of analog inputs for a 1500?

Let me explain what I'm trying to accomplish, then maybe you guys could point me in the right direction.

I have a 0-10 VDC encoder on a shaft (yes, still doing the jam detector...see other post). I would like to make the function as follows:
0V to 2V = dormant
3V to 6V = initiate sub-routine 1
7V + = initiate sub-routine 2

I know I'll have to use comparators for the JSR.

any help? I'll post the program when I'm done for your comments...

Jnelson · Mar 4, 2005

The source A and B in the lim instruction should be entered in the raw integer format.

stasis · Mar 4, 2005

responding to the first part of your answer...not sure what you mean by 'raw integer format'. I can write this program out in PicoSoft without the sub-routines, but I'm not familliar enough w/ Logix.

stasis · Mar 4, 2005

ok, I figured out what I was doing wrong when inputting the fields. However, now there are question marks under the fields that I put a # value in, like this:

Limit Test
Low Limit 3
?
Test I:0/6
?
High Limit 6
?

so, what am I missing/not understanding?

stasis · Mar 4, 2005

ok...again,duh! The question marks under the values will change when voltage is applied!

stasis · Mar 4, 2005

stupid enter key...grrr. Anyway, the error I'm now getting is 'Address must be specified to the word level' and I'm not sure what that is...In my defense, I did say this stuff was all new to me.

kamenges · Mar 4, 2005

Try entering your Test value as I:0.6, which is a word level designation. I:0/6 is a bit level designation, which is why Logix is complaining.

Keith

Jnelson · Mar 4, 2005

Sorry I was so brief.

The low limit and high limit have to be entered in the integer format. Your analog card is going to give you a signed integer input value between 0 and 32767 which corresponds to 0 to 10 volt. What you enter for the low and high limit is a percentage of that full range. For instance one of the values you want to know is 6 volts, to figure out what the value should be simply figure out what 60% of 32767 is and plug that value into the lim instruction.

Does that make better sense?

Martin T. · Mar 4, 2005

How about using SCP

input ?

        input min 0

        input max 32767

        scale min 0

        scale max 10

        Dest      N7:0

Then use John's LIM.

Ken Moore · Mar 5, 2005

I agree with Martin, by scaling the input it's a lot easier to trouble shoot later. You can tell what the input voltage is at a glance. You might consider using 0-100 with an implied decimal place. 55 would be 5.5 volts.

Ken

Ron Beaufort · Mar 5, 2005

got the book? ...

Greetings stasis,

how is your analog input going to be connected to the MicroLogix 1500? ... for the sake of discussion I’ll assume (gosh I hate that word) that you’ll be using the 1769-IF4 analog input module ... if so, then the Compact I/O Analog Modules User Manual will probably come in very handy ...

I suggest that you take a look at the chart on page 4-10 [Adobe Reader page 56 of 130] to begin with ... this gives a good overview of the available configurations and the data readings that you can expect for each type of input signal ...

JohnW · Mar 7, 2005

As Ron says -- Read The .... Manual. However the 1769 IF4 input modules are configurable, from RS Logix you can set the input scaling etc. Set your scaling to "engineering units" 0-10000 then the math is easy.

Analog in RSLogix?

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