software program problem tri-logic/edu ver 4.61

I am stuck on the first lab1 washing machine. Circuit 1 after the 2 input switches (start I/2 and door I/1) I can't place The T/1 NC contact after the door switch which applies voltage to O/1 heater coil. What the heck am I doing wrong? Everything I have tried places a parallel branch around I/1 door switch and there is no way to continue the branch circuit to the output coil)/1 heater. Help

Stephen G Walk
[email protected]
Madison Heights Michigan, USA

Stephen,

Probably what you did wrong is start thinking about the Inputs (Start, Door, Timer) before you make a list of the Outputs that are going to be needed to do the actual WORK of washing the clothes. I find it easier to start thinking about the Outputs (machine motor, heater, cold water valve, hot water valve, pump solenoid, wash cycle solenoid, spin cycle solenoid, and so on). Heater? Your machine has a heater? Must be a deluxe model! My old home machine does not have one of those....

Everything I have tried places a parallel branch around I/1 door switch and there is no way to continue the branch circuit to the output coil)/1 heater. Help

Click to expand...

Do not limit your program to only 1 rung. You are allowed to use as many as you need to solve the problem. There are ways to continue the logic on the 2nd, 3rd, and so on until you finish the LAST Output that is doing WORK.

See the attached picture for these mysterious ways to make a PLC behave.

Trilogic version with Fill Timer (can't imagine heating BEFORE filling) and Heat Timer.

Everything I have tried places a parallel branch around I/1 door switch and there is no way to continue the branch circuit to the output coil)/1 heater. Help

Click to expand...

Now after using the Trilogic, I see your problem. Notice on the "Insert Circuit" menu, there are 3 sets of contacts: "1" puts the next one in series, "2" places it parallel, and "5" encloses parallel branches. See the Trilogic HELP menu for more complete explanations.

Washer lab1 tri-logic/ver 6.41

I understand about the circuit insert that was a no brainer. What I can't do is insert the NC contact from T1 timer rung1 to start the parallel rung to O1 heater. I can't figure out how to get the software place the bits in the right place.

Stephen,
Your Trilogic version is severely limited in what it can do (even Version 6 does not have the needed capabilities), so you must improvise - figure out how to do the job with the tools available. You cannot place rung branches as needed but you can make a new rung that does the same thing. This is a case where you must look at the forest (the overall program results) instead of the trees (the individual rungs which are not important as long as the job gets done).

Here are the first Rungs 1 and 3 "no brainers"! I will leave the others for you to do.

Thanks for your help. I Thought the lab book where the practice plc programs had been tested. I could not figure it out. I have been looking around for a Plc to program and fool around with for aligning solar panels
to the sun. Found Koyo click plc downloaded there very cool software. Plc brick cost 69 bucks and you can add I/O blocks only needs a P/S 29bucks.
Thanks again Steve Walk

I know that Phil Melore tests his programs, but remember that PLCs are not all made the same. Your Trilogic happens not to allow rung branches with separate inputs and outputs. You can have two or more ouputs on different branches, but only if there all parallel ouptuts have exactly the same input conditions.

You could try the LogixPro Simulator from thelearningpit.com. It will let you do what you needed for this lab exercise.