communication of DAQfactory with a siemens steep 7-300

[simonmuthike]

I want to automate a plant using daqfactory but they are using step 7-300 PLC's as RTUs. so which protrocol will i use please help.

[AzeoTech]

I believe the S7-300's only talk their native protocol. I could be wrong, you'd have to check the manual or the web to see if it talks Modbus or not. If I'm right, then you will have to buy an OPC server. Siemens does not publically release their protocol specification so we cannot create a reliable native driver. I'm sure Siemens would release it to us if we paid them a lot of money (as I'm sure the OPC server publishers did), but then we'd have to double the cost of DAQFactory!

In my personal opinion, the days of proprietary protocols are numbered. I strongly recommend, when selecting hardware, that you use devices that use a standard protocol like Modbus. This will ensure that you have a wide variety of connectivity choices. This doesn't apply to USB or PCI hardware as they require proprietary connections due to their very nature, but applies to any hardware on ethernet or serial connections.