Since the C-More Micro is the master, we just need to tell the C-More Micro where to get
the data it needs to control the screen and enable that feature.
In this example we have told the C-More Micro to watch PLC address 100 and use that as the
screen number.
Screen numbers can be 1-999 with a ZERO telling the C-More Micro to go to the previous screen.
Lets try a few.
In this example we have 5 screens with each one a different color.
Let’s try 2 and we go to the YELLOW Screen, a 3 takes us to the AMBER screen, and a 5
takes us to the RED screen, with a zero returning us to the previous screen.
Lets see how to set that up.
To setup the panel for PLC control of the screen number, go to the Navigation windows
function tab and click on PLC to Panel, or go to the Setup Menu and click on the same
thing.
Under the PLC to Panel tab – We need to tell the C-More Micro which TAG to monitor
to use for the screen number.
We’ve created one on a local PLC called “SCREEN NUMBER.”
It’s at address 100 on that PLC.
You simply check this box to enable that feature and you are ready to go.
Notice that we can also control BEEPS from the PLC and you can control the Backlight
from the PLC.
There are separate videos on how to do that – be sure to check those out.
Now that we have enabled screen control from the PLC, we just say click OK and Simulate
it, save the project, bring up our simulator.
Now the C-More Micro is monitoring this TAG down on the PLC to determine its screen number.
If we change this value to screen number 3, then the C-More Micro sees that and reacts
accordingly.
Change it to 5, again it see that change in the TAG so it changes the screen number.
There ARE a couple things you need to beware of so you don’t get stuck ….
1.
The C-More Micro watches this TAG for CHANGES.
So for example: If the PLC writes a 2 to this TAG, the c-more micro sees that and changes
to screen 2, our lime screen.
That’s correct.
BUT if a user changes the screen to screen 4 for example –AND THEN the PLC writes a
2 to this TAG to try and get it back to screen 2 – nothing happens.
The reason is, the C-More micro was watching this TAG, it WAS a 2, it changed to a 2, so
the C-More Micro didn’t really see a change so it didn’t react.
The best way to handle this is to have the PLC monitor the current screen and then update
this TAG with that value.
So when the user changes to screen 5, the PLC would see that, it would update this TAG
to screen 5, so now when the PLC wants to change it back to screen 2, the C-More Micro
will see the change, and actually do what the PLC asked for.
So again, the C-More Micro has to see this TAG CHANGE in order to react.
2.
Issue #2: The Number Formats Matter: Be careful when specifying screen numbers: for example,
this TAG is specified as an unsigned integer in our simulator.
That means the C-More Micro is expecting an unsigned decimal here.
But if in your PLC project you have the screen number defined as BCD then the screen number
you send is NOT going to be the screen number that the C-More Micro gets.
For example, if you send a screen 10 – a BCD 10 – the C-More Micro is going to interpret
that as a 16 and send you to screen 16, not screen 10.
So make sure the data type here and on your PLC project match.
That’ll save you a lot of headaches.
That’s all there is to controlling Screens from the PLC – be sure to check out the
other videos in this series.
And as always, please send us any topics you would like to see covered – or - any other
comments for that matter – we appreciate the feedback!