How does labview opc communication with plc affect timing for the actual plc application

[Olivioloyer]

Hi Everyone, 

I have a doubt and thus want to start a discussion regarding communication with PLC's from NI OPC server.

Let's imagine you have a production machine like a caping machine for a bottle production line, let's say the PLC on this machine is a Siemens S7300 which according to NI is compatible with NI OPC server.

The PLC would have already been programmed by the company who sells the machine to control it correctly.

The question is, if you'd like to add an interface, and all the capabilities that LabVIEW offers to this machine by controlling/monitoring its PLC, returning its alarms etc...

In that configuration is there a possibility that the LabVIEW application you would devellop affects the PLC's Behaviour and thus the machine functionality or yield and thus would have a negative impact?

Thanks a lot for your answers.

Best Regards,

[JuDa]

Hi Olivioloyer Good Morning:

The issue here is that if you want to control, display and log data and funcionality from that PLC through LabVIEW you will have to change the program on the PLC to work correctly with your Interface and Alarming program that you will create in LabVIEW. If you develop a well designed architecture and an efficient code there will be no negative impact on yout PLC, on the contrary you will expand the funcionality and capability of your application. 

Note: You will need to change your PLC program to achieve correct functionality with what your LabVIEW code will do.(Send and receive control commands). If you just want to monitor your PLCs behaviour, your code will be much more simple and maybe no change will be required on the PLCs program.