OPc writes from external application

Hi,

Total newbie here guys so go easy on me...;-) I am writing an interface to a PLC using an OPC server (RSLinx Gateway) The application I am using is a custom web app written in Java (not by me) and there is an OPC widget that i use to connect to the OPC server and read and write tag values.

All is fine so long as the tag is defined as analog and it has a name. I can read and write all day. The problem is that when I am working with a digital bit like B3[2]/19, etc...the type is DINT and B3[2]/19 and /18 are used as a toggle.

The app I have needs to be able to toggle that bit. I can read the bit fine. When I do a opcTag.write(oValue), where oValue equals 1 or 0 - I have tried sending the 1 or 0 as a string and an int and no go. No matter what, it will not write and the method call returns null...I am lost.

Any help or information would be helpfull

Thanks...

The OPC data type should be something like BOOL or DISCRETE. I do not remember the standard OPC data types of the top of my head, but a bit is definetly not a DINT (double integer or 32-bit word). You only need to address a single bit in a word and from your address examples you are working with a maximum of an INT (16-bit word).

Darren