3 state switch

[Nogmor]

Hi,

 

the visilogic has a nice Auto/Off/Manual switch images but - how do I use them?

 

I need a 3 state switch, but the only options i could find are the "range of images" and the 2 state bit-switch.

 

Thanks,

 

Mori

[Michael_P]

Hi Mori, 

You are on the right track, there is no simple 3 state coil to perform the operation. You will have to use the image by pointer to drive the images on the HMI. I have written a 3 way switch example for a on/off/auto pump system. This may be of great use to you as you can see i have used the Image by pointer value within the logic to drive operations. 

http://forum.unitronics.com/files/file/35-%7B%3F%7D/

 

Thank you 

 

[Nogmor]

Hi and thanks!

 

I am currently using VisiLogic 9.4.0 and the file you created (is apparently) from the newer 9.5.0.

 

I am having some difficulties using the 9.5.0 version, any chance for a 9.4.0 version of the file?

 

Or just a general explenation on how you achieved the 3 state switch? (Maybe multiple coils?)

 

Thanks!

 

Mori

[Walkerok]

To make the three images making up the hand off auto. You will set up an image by pointer and designate an MI for selecting which image you want and an MB for when the image is touched.

 

The only problem with this is how will the PLC know if you were trying to go from off to auto or off to manual? The answer is that if you use the actual three picture image "by pointer" as the touch object you never can know which direction you wanted to go.

 

If you put two buttons under, or above, or wherever to indicate left rotation or right rotation then you can write a simple logic (but it won't look as nice on screeen) so that if you touch the left rotation your switch moves to the left or the right rotation your image will move to the right. Note if you go this way that you need to put the off position as image number one and either the hand or auto as images number zero or two.

The logic is as follows:

You can make the H-O-A switch only work as described by Michael, but then you will have to cycle through the other positions to get where you want to go.  If you chose this method then you will want an activation timer delay so your process does not automatically start as you cycle through either hand or auto to get to off.

 

Personally I believe that this is one of those things where an ald fashioned real 3 position switch is just the easiest way to go.

 

Good Luck

Keith