Newbie Question Array / SQO help

[jersbo]

I am a college student and am having trouble programming my final project. Our project is an automated can crushed and the part I am having trouble programming is a pneumatic robotic arm that will pick the can up and move it onto a belt which feeds into the crusher.

I need to program the arm to run in a continuous sequence such as (raise up, swing left, lower, open claw, etc...). It is wired to my output card and has a total of 9 movements. My instructor said the easiest way to achieve this is through a SQO instruction, but he himself doesn't know how to set it up.

My questions are how do I set up the array? Do I need to use 1 or 2 dimensions? How do I address a certain point on the output card to a certain point within the array?

I have read that maybe MVM and MOV commands might be easier to work with rather than SQO's. If this is true could you give me some basic information on how to get started.

I am using RSLogix 5000 v12 to program it on an AB ControlLogix 1756 system.

 

[TConnolly]

When it comes to homework problems we will help you, but you have to show some work yourself.

I suggest you first get the instruction set reference manuals and review them to see how the SQO instruction works. You can find the manuals at ab.com in the literature library.

As for writing the SQO output word to actual outputs I suggest that you have the SQO write to an internal DINT tag instead of writing to an output card. Then use XIC OTE pairs to write the state of each bit in the internal DINT tag to an output bit. This is a common method in industry as it makes troubleshooting easier for the maintenance technicians who will have to maintain the equipment.

One thing that you may notice is that an SQO instruction acts pretty much like a counter with the added feature that it copies sequential numbers from an array to a single tag. Once you realize that it may occur to you that you could just use a counter and by comparing the counter accumulator to a desired step number you can turn on various outputs. Its a lot simpler to program, and its a lot simpler for someone reading the program to follow than having to look at an array of numbers, decide which number is being used from the array, and then work out the binary bit pattern of the array number.


P.S. You really need to encourage your professor to get up to date (version 19) on your copy of RSLogix5000. If your lab is using an L5x series processor then your professor can only update to version 16.