Maybe Variables

Hello all, I am a real PLC newbie that is actually a Network Admin with another hat to wear. I have went to one class (2day) to learn a few of the basics. So here is my question. If I have a control panel that has a limited amount of switchs and buttons can I have a particular process rung dependent upon the sequence in which the switches or buttons are pushed. For example. I want the output to be that of 3inces to move a device if buttons A,B, then C are hit in order. If want the device to move 4 inches I would push buttons B,A then C and so on. Is there a better way to do this. We "will" be using Rslogix if the solution is software dependent. I am also a programmer so my first thought was a variable to hold the bit until another sequence is initiated, but since I have yet to actually touch the software this makes it a little more difficult to know for sure. Thanx much in helping a bigtime newbie

first off, I would be inclined to say that this is possible. however I think there is probably an easier way of doing this. Some more detail might help. Just how limited is the amount of switches and buttons on the control panel? How many I/O does (will) your PLC have. How many different travel lengths will you require? What device will you be moving?

Couple quick solutions which may be easier before my lunch break is over....Selector Switches would be one possible solution I'd look at. Another solution would be to put a Panelview in the control panel. A panelview 300 would be a good choice if your limited on space and also is quite inexpensive (about 300 bucks I believe plus 250ish for programming software).


Any further questions let us know. I'm glad to help out a newbie cuz I am one too


Also, just curious where in WI your from?

r

Well I am just wondering basically we are not quite ready to do this I just was wondering if it was possible in Rslogix cause our class used a different piece of Sw that was not capable of doing such. Up here in Keshena. I will keep in mind the rest of the info you mentioned thanx

You could program the ladder code to do what you want using RSLogix. Your programs ability is only limited by the instruction set of your processor and your imagination. But I think as hd_coop said it would be easier to use a selector switch or HMI to select the length. However, you could write some code that depending on what button is pressed moves a number to a mem location and then indexes the data to provide room for the next and so on until a preset number of moves has been detected. You could then compare this number sequence and enable the appropriate rung. An cleaner and even easier approach would be to replace the 3 buttons with 3 toggle switches and do a binary count and compare.