When developing a data acquisition applicatition where a pc will be getting the data from a plc via ethernet what are the pros and cons of using an activex control versus an opc server?

[simpsjf]

the plc is an allen-bradley plc-5/40E. OPC server candidates are RSLinx and Software Toolbox. Software Toolbox also supplies activeX controls for the PLC.

[Greg Caesar]

Both are a suitable solution for communication with the PLC. Typically, we see a much larger preference for an OPC server, as OPC servers have a common interface from the OPC Clients. However, Active-X controls can have a custom programming interface (properties, methods, events) that can make them more difficult to implement in your program.

Greg Caesar
National Instruments, Applications Engineer