Listening on a COM Port for Data from an FX2N

[jtaylor42 0]

I am reading data from an FX2N via the COM port. I have the device Y5 desingateded as the end of cycle "part count". Currenty, in order to get the data I have to write to the plc via the com port with a sting that tells it to send back the data for the 1st Byte of the Y device. I then compare the result with a byte mask to see if the bit at position 5 is a 1 or 0. I am doing this every 200ms to make sure I can capture in changes in the bit. This all works. My question: Is there a way to configure the plc so that I all I have to do is open the com port to the PLC and just listen for the data (ie Y5 changing from a 0 to a 1) instead of having to send the write string and waiting for the response every time? The kicker is I am also reading 2 values from the X device. So I would need my program to just open the com port and wait for a "data recieved event". When this happens I would get the data, determine which device and byte it came from, and record the value. Is this possible? Thanks in advance.

[Sergei Troizky 26]

You did not specify what is communicating with your PLC. What device or software?

[jtaylor42 0]

I am using a vb 2005 program that I wrote to collect the data. The server it runs on is using virtual serial ports which are connected via ip to ethernet-serial converters on the other end. The plc's are connected to the ethernet-serial converters. It looks and acts just like a pc connected directly connected to plc via the com port.

[Sergei Troizky 26]

Then why don't you use ready DDE driver?

[jtaylor42 0]

Where do you get the dde driver and how does it work? Do you have a link to some docmentation on it?

[Sergei Troizky 26]

Email me to truyzky@yahoo.com for the DDE driver details. Edited 19 May 2006 by Sergei Troizky