microLogix 1000 questions

dana123 · Mar 14, 2009

I am wiring up my first MicroLogix 1000 and am having trouble getting the inputs to work. I am using SPST switches. I wired up one end of the switch to I/0 and the other end to AC COM. Is this correct?
I tried another switch into I/1 and the other end into the same AC COM. Neither switch shows anything on the input of the Micrologix lights. Do I need a wire from AC COM to one side of the AC coming into the Micrologix?
The manual is not real clear on this. Any help would be appreciated.
Thanks,
Dana

Ken Moore · Mar 14, 2009

For inputs to "see" an event you must have a complete circuit. So you will need both the supply and the common in you circuit. For sinking inputs, the AC common is connected to the common on the input module, and the supply is routed through the switch. So when the switch is "made", you have flow from the AC supply through the switch and to the input. The PLC senses the "flow" and the input goes high/true.

mel_w · Mar 14, 2009

Hi
take 1 of your supply cables to ac com and connect the other wire from your supply to the switch and then from the switch to the input

i.e
switch
supply L ----||---- I1
supply N ---------- ac com
regards mel

dana123 · Mar 14, 2009

that worked great, thanks so much.
I have a software question now.
How do I ask for a value from the analog inputs?
I have read the manual but it doesn't give any examples.
It lists the voltage inputs as I:0,4 and I:0,5
aren't those the same as the other switch inputs?

Thanks again,
Dana

bernie_carlton · Mar 14, 2009

An individual input is I:0.0/0. The '/' notes the designation of a single bit.

I:0.4 and I:0.5 are complete words. (And by the way those are periods, not commas)

Attach a variable voltage to the designated input with the common of that voltage attached to the common. View I:0.4 as a decimal (check the lower right of the data table for a spot where you can change the 'radix'. Now vary your voltage input. Get the idea?

I your ladder you can MOV I:0.4 to an 'N' register. The numbers you take in can be used in any math instruction. You can compare these inputs to other numbers. Are you getting any more ideas?

Mickey · Mar 14, 2009

See table below for raw values for your voltage inputs.

dana123 · Mar 15, 2009

thanks

I sure appreciate all the help and also this forum.

Thanks again,
Dana

dana123 · Mar 21, 2009

output question

One more question, if that's ok.
The manual shows a meter hooked to the analog output. I tried hooking a small
toy motor to it and I guess there isn't enough current to drive it.
What will it drive? I'd like to vary the speed of a small motor if possible.

Thanks once again,
Dana

OZEE · Mar 21, 2009

What are the specs on your motor? How is your output configured?

dana123 · Mar 22, 2009

specs?

That's a good question. I don't have specs on the motor. It is just a small 10-20 volt motor, geared down to about 2 RPM.
I sort of assume that the ML comes configured for voltage, but I suppose I should check.
I did put a meter on the output and I can vary it from 0 to 10 volts, it just doesn't drive the motor. When it is hooked up, the voltage drops to .5 volts.

Thanks,
Dana

leitmotif · Mar 22, 2009

dana123 said:
That's a good question. I don't have specs on the motor. It is just a small 10-20 volt motor, geared down to about 2 RPM.
I sort of assume that the ML comes configured for voltage, but I suppose I should check.
I did put a meter on the output and I can vary it from 0 to 10 volts, it just doesn't drive the motor. When it is hooked up, the voltage drops to .5 volts.

Thanks, Dana

Dana
PLCs are not a magic box. They cannot do anything and everything. What is the voltage ie AC or DC that you are varyng and what is the allowable current?

What kind of motor AC or DC what is the current?

You have to know these things before you hook em up. Trial and error and smoke testing gets expensive. I think you are overloading the power supply.

Dan Bentler

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