I/O question

Interesting question.  

 Yes, but it might take some work to get there.  VBA as a language can do a lot.

 It boils down to what the controller can accept as a signal.  What are you looking to send to it?  A command?

 Does it have PC software that can talk to it already?  If so, another method might be to call the other software to send the command rather than trying to talk to the controller directly.

Jim.

So I just took a quick look through the EZPlus manual and don't see where ti really allows for external programs or to be controlled by one.

 I think your best bet would be to talk to the vendor directly and see what they suggest.   PLC's usually provide some method of getting data to/from it fairly easily.

 If you don't use the EZPlus software or some other utility, then it means from VBA you would need to do all the low level stuff; establish a TCP/IP connection, form and parse packets going back and forth, take care of communications, etc; quite a bit of work if you go that route.

There is an upload/download capability I see built into EZPlus, so I'm left wondering if you could not use that feature, but it would need to be externally callable by Access.

I'll take another pass through the manual a little later, but your fastest answer will probably be to call the vendor direct and just ask them how an external program could possibly interface.

Jim.

just wanted to jump in

years ago, I wrote some code in Pascal to interact with a signal generator.  I've also written stuff in Excel to interact with data collectors, so if we can get some specs, I think we can do it from VBA too.

We obviously, however, wouldn't be able to test anything since we don't have the equipment that you do.

Crystal I would really appreciate any help

what port is your controller plugged into?

also, as Jim mentioned, you will probably need to talk to your vendor to see if the controller can even acknowledge the information

I talked to the vendor's tech support and he advised me that it would have to be sent to the RMI using a modbus protocol.

so the question is:

can the controller accept a READY signal and process it?

and then the next question, which Jim also eluded to, is, if you already have code to send information to the controller, why not just add this to that?

The tech said that it could receive and process a signal sent in Modbus protocol as in turning on a bit. And there is a stand alone programming software called EZware that is designed to program the unit. That software and a VNC viewer are the only ways that I have of communicating from the PC to RMI and not something that I can add to.

OK, after a little footwork, have a look at this:

http://www.maplesystems.com/cgi-bin/beimatdongon/TechNote/09075099.pdf

 This is what the tech was speaking of.   By activating this gateway, you can control the HMI and devices connected to it.  To do that, you'd use the ModbusTCP Master protocol.

To help with that, consider getting something like this:

http://www.modbustools.com/modbus_activex.html

which is an Active-X control that would handle a lot of things for you.  You'd then start writing code that looks like this (look at the bottom):

http://www.modbustools.com/mbaxp_quickstart.html

Just make sure if you are going to but an active-x control, make sure the vendor says it will work with Access, or will give you a refund if it does not.  

Jim.

great information, Jim ~

Thanks Jim, I will give this some effort and let you know how it turns out!

Holler if you get stuck anywhere, but I must admit it has been quite some time since I did any work like this.

Thought I'd have a good handle on it, but it was quite a surprise to see how much has changed in this area and what's now available.

Definitely an interesting question though, so thanks for asking it!

Jim.