The procedure for controlling a Viewmarq via Modbus
for most PLCs would be to send the message as a Modbus write, then when that is complete
use a read instruction to do a bunch of Modbus reads of the command block to see when the
Viewmarq is finished and then finally, read the Reply Status Block, to see if the result
is "OK".
If so then everything is ready to go, if not, then there was an error.
The good news is you don't have to do ANY of that with the Productivity 3000.
It has a built in Viewmarq instruction that does all of that message transfer and error
checking for you!
Let's take a look ...
Let's start a brand new project and open up the hardware configuration.
Make sure the controller is in Stop Mode and then hit this button to auto discover all
of your hardware.
This dialog is warning me that this PLC doesn't match my project -- we know that so we'll
tell it to ignore all of these messages -- and here is our system.
If we double click on that we can see that we have a small base, with a processor and
an input simulator.
Now we just double click on the CPU to configure it.
We're going to connect to the Viewmarq via the serial port in this video, but if you
were using the Ethernet port you would simply click on that tab.
Over here in the serial port tab, we just need to match the settings that are on the
ViewMarq.
Our ViewMarq is operating at 38 4, it's at address 1, Odd Parity, 8 data bits, and 1
stop bit.
Perfect.
Over in the ViewMarq software, go ahead and establish communications between the PC and
the Viewmarq.
Our productivity 3000 project will be using serial Modbus so let's set this to the same
thing: Modbus, 38 4, odd, 1 and 8.
Once we have configured that connection, we can now go check out the LED display configuration.
Since we're connected via Serial, we want to make sure we are talking Modbus, we have
the right parameters, and for this demo we'll turn on the diagnostic LED.
Perfect.
Well, now that the hardware is setup, the software is trivial.
We just drop a ViewMarq instruction in place.
Let's scroll down until we find it.
Right here.
Drop it on the rung.
And fill in the blanks.
We're using the serial port, so we'll select that.
The node address of the ViewMarq is 1 -- that's correct.
Next we grab our ViewMarq string by pressing "copy" and we paste it in here.
And then finally, we need to define a TAG for the Syntax Response.
Let's call that the ViewMarq Reply.
So we setup our serial port, we pasted our string in, and we setup the one required tag.
Hit OK.
The software recognizes that we created a new tag, and it asks: do we want to go ahead
and create that tag?
The answer is yes, but, I'm going to expand the length of this to 128 characters to give
the ViewMarq plenty of room to reply.
Let's add a contact to enable the message -- we'll use the input simulator so let me
go back to the hardware configuration, double click on my input simulator, and let's define
this first switch as our message enable.
Now that we have done that, we can place a contact over here and we can enable this instruction
by flipping that switch on the front of the input simulator.
Note this little arrow right here on the ViewMarq instruction.
That tells me this is an edge triggered instruction.
So the rising edge of this contact will enable this instruction, and then it will run to
completion over several scans all by itself.
You don't have to worry about it.
Let's go ahead and transfer our project over to the Productivity 3000.
Now I'm gin got reach down to the input simulator and flip that enable switch we just setup..
And there's our message.
Easy.
So all we did was setup the Productivity3000 hardware, setup the Viewmarq hardware, drop
a Viewmarq instruction on the screen and fill in the blanks.
And that's all there is to it.
That ought to be enough to get you going.
Let us know if you have any questions.
Automation Directs Customer Support is always free and just a phone call or e-mail away.
Performance plus Value ... That's productivity.
From Automation Direct.