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Hello !

 

I am a trainee and I have a project to do. I have to command the operation of a oven and I'm trying to do that but I have a problem.

By the way I'm using Visilogic, a V570 screen, a  snap-in V200-18-E3XB and an expansion IO-RO16. 

So my problem is the following : I want to test my program but when I force a input to set or reset after that this unput is not working anymore, it's like blocked. As you can see on the image below.

So I'd like to know if there is something I can do to get back the good operation or if I'm  doing something wrong. (sorry if it's in french but I am :3 )

 

Thank you in advance for your help.

J.MOREL

 

forumunitronics.png

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Force is for INPUTS, Set & Reset are for Memory Bits.

A Bit that is manually Set or Reset will remain Set or Reset until there is activation of a Set or Reset Coil in the ladder.

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In your picture, you cannot change the value of MB111 manually since it is being activated by a Direct Coil on every PLC scan. In order to affect the value of MB111, you must change MB100 or MB40.

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Your MB 111 is being controlled by a direct coil every scan.  You need to change the value of MB100 or MB 40 in order for MB 111 to be affected.

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Flex727 and Cam, I get that, it was just to give you an example of what i was talking about.

AlexUT, I tried to Right-click on Set/Reset but nothing happened ! What have I done ?!

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First of all I have to make an oven in operation.

So if the button "Start Cycle" is pushed and if the temperature sensor is detected the output 32 will turn on which is going to switch on the oven. 

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Once you force and  Input to 1(via info mode or online mode) it will stay one until you force it to 0 or cancel the force(return it to normal operation).  This can be done as described by Alex or from the info mode on the PLC.

 

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Oh, sorry, I set and reset things that shouldn't be, like you told me. But now I can't make them back to their normal setting.

I can't cancel force and the reset don't make it back to normal.

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You can never manually Set or Reset any bit that is being activated by a Direct Coil. The only way this can happen is if the coil is in a subroutine that is not being called by the Main (or other) Routine. Post your code here and we can help you.

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Ok so here is my new program.

I have a problem on the net 1, MB100 doesn't turn on whereas MB78 is turned on.  And it's the same for the others nets. Is it because I forced them before even if it's supposed to be forced ?

forumunitronics2.png

forumunitronics3.png

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Are you calling that subroutine in the Main Routine?

As I said before, FORCE is only for INPUTS, not MBs. You can only manually SET or RESET a bit if it is not being activated by a Direct Coil in the ladder. Also in your picture in net 1, you have a SET coil (MB100) being activated by a Direct Contact (MB78). You cannot manually Reset MB100 as long as MB78 is on.

Bottom line, only INPUTS can be forced, no other memory operand can be made to take on a value manually if it is being assigned in ladder on every scan. You cannot override the ladder logic from VisiLogic.

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On 4/14/2017 at 9:55 AM, Flex727 said:

Bottom line, only INPUTS can be forced, no other memory operand can be made to take on a value manually if it is being assigned in ladder on every scan. You cannot override the ladder logic from VisiLogic.

Just want to clarify - both INPUTS and OUTPUTS can be forced, but I believe the rest of my statement about other memory operands stands.

Thanks for the heads up, @Ausman!

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One thing that is missing to my eye is setting the power up values, and likely all the coils need to be done as reset.  Perhaps the program is carrying over previous operations?

I would also be doing a full initialise and reset on each trial of a new program.

There are many other operations in this program that are not shown that could be affecting things.  Don't forget the ability to find operands etc by right clicking them in the operand list and doing a find.  This is invaluable in ensuring that you haven't forgotten/lost track of a wrong placement somewhere that can affect things.

cheers,

Aus

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I finnally found what I was searching for ! In fact all I wanted at the beginning was to reset everything in my LADDER (sort of) because I forced things that I KNOW can't be forced but I did and it worked but at the end it was blocked and I could'nt do anything. That's why I wanted to restart everything.

So I found the reset options in the PC settings, and I did  "Initialize and Reset" and I was excaltly what I wanted to do !

Thanks for your help ! :)

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