Analog I/O 3

[microgrip]

I am new to programing analog input and output modules.
I have installed a mixed 4in/2out GE analog expansion module
as part of the control on a machine I am rebuilding.
Can someone help me understand what type of function blocks
I can use to give a specific analog output to a volume card?
This is a 0-10vdc output.
I think I have the input side covered but would welcome feedback on those as well.

 

[djs]

I believe that the analog values show up as integers (16 bit) on the input and output data space. %AI for the analog inputs and %AQ for the analog outputs. The exact range of the integer values depends on the card and the configuration of that card. To set an analog output, move or write a value to the cooresponding %AQ register.

 

[dV8r]

djs is correct.
The combo analog module will have a value of 0-32000 that represents the 0-10 volt output. i.e. a MOV "16000" to %AIxx will output 5 VDC at the module. Where "xx" is whatever value you assigned the module's outputs.

 

[microgrip]

Thanks everyone for your response. I would like to elaborate
further.
The AI's will receive signals from 4 separate linear transducers on the machine. This is a Injection mold machine. One for the clamp position, injection unit, screw position and ejector position.
As far as I understand, The values I will see at the function block I will use for the AI's will be 0-4095
after the processor scales the 0-10,000dc millivolt signal. I thought a LE function block would be one I could use
while closing the clamp for example.
I think the same values are true for the AQ but moved as an output voltage as you both stated previously.
So, if I wanted to send a 3volt signal to a amplifier card
that is controlling a proportioal valve, would I move a value of aprox 1200 through a MOV function and expect to see 3vdc at my AQ output terminal.?

 

[djs]

Should do it if all of the scaling is correct. Please note to dV8r's reply that the mov should be to %AQxx not %AIxx.

 

[microgrip]

Thanks for the input.
As I am looking at the AI values represented at the
logic elements I see that they are in fact 0-32,676 for 0-10v inputs respectivly. The scaling is all internally done.
Thanks dV8r...
Anyway, I just programmed my first few rungs of analog I/O
and actually achieved movement of the machines' clamp.
Exciting to say the least. Now comes the real fun........
Firing outputs on the fly and sequencing the machines different functions through an entire cycle.
I think I will take each set of machine functions separately
and combine them after the basic logic is written.
Does that sound like a sensible approach?
I actually had no problems with my control wiring either.
Usually I find a misplaced wire somewhere but not this time.
Thaks for your inputs.....and outputs

 

[amptramp]

microgrip:

FYI, the 16 bit values (0-32767) stored in the analog input and output registers are referred to as "raw" values and typically not considered as "scaled" values. The raw values are a function of the A-D and D-A converter electronics, i.e., a 15 bit A-D converter has a raw value range of 0 to 2^15 or 32767 (32768-1).

Typically, these raw values are "scaled" to engineering units such as inches or degress F. By using a little algebra, your clamp position could be compared to some value of inches as opposed to a number that is somewhat meaningless. If your interested in scaling, let us know and someone will provide the necessary information.

 

[microgrip]

Thanks amptrap,
I'm learing alot here. So far I'm ok with just seeing the raw values but will change them into eng units, most likely inches. Linear positioning is what I'm dealing with now. I'm using a GE micro 64 with a analog expansion unit.
Changes will be made on a laptop designated to the machine
for now.
I'll keep posting my progress. I really appeciate the input I getting.

 

[microgrip]

Hello everyone,
I am now in the process of progaming my injection press and with some success. All moving members are working and i can set speeds and pressures for them. I see now how the raw values will be much too large to deal with once I get the initial programming done. I have been trying some different math functions to get the values to a smaller understandable number. Not having much luck here. I need training.
I have a maximum clamp stroke of 13.77in (350mm) and would like to see the analog input for that stroke sensor in inches. How can I accomplish this?
I am also realizing that in dealing with analog I/O, the logic becomes extensive in a short time having to dedicate
move functions everytime I need to perform a different operation and make sure previous move elements are shut off etc. Things can get out of hand quickly.
Thanks. Hope I am making some sense.
Please correct my terminology where needed.