interfacing of PLC with PC and HMI

[hizdadd]

i need to interface a siemens PLC(300series) most probably 314ifm, with a HMI(LCD screen) and a personal computer for data aquisition,
now the problem being cost, and me not being able to buy modules and cards(which cost a lot), that is why im using the 314ifm which has integrateed analogue inputs and outputs.
now i understand that the interfacing can be done through MPI port, but there is only one MPI port available in the 314ifm, so either i can interface it with the PC(personal computer-desktop) or the HMI.

so here is what i was thinking interface the PLC with the PC directly and then interface the HMI with the PC, so i can aquire data on the PC, and then display that data on to the HMI.
will this be possible? if so which HMI will i need to use, a siemens one/can some other be used?can the data be displayed real time?will control be possible through the HMI(inputs to the PLC) or will it only display?
also are there any models with 2 MPI ports in the processor itself? the maximum cable length of the MPI,because my PC will be 70 meters away.
the PC is needed for data logging(will be using labview)

 

[IRstuff]

?? Wouldn't the PC come with a "HMI?" If you can talk to the PLC with the PC, partticularly with Labview, why would you need a separate HMI?

TTFN
faq731-376

 

[cairnhill]

MPI is multi-point-interface and is based on RS485 therefore you do not need two ports as all other ports are connected together by two cables with terminating resistors at each end.
Your HMI and PC would have to have ports capable of connecting to the network. You can get (or used to be able to get) PCMCIA cards for your PC. If the HMI is Siemens it will probably have an MPI port.

 

[LunaApplication]

As "cairnhill" said, if you want to communication with 314ifm via MPI on your PC or HMI, you need to MPI card (like CP5611/CP5613 supplied by SIEMENS company) or use PC-Adapter on your PC or HMI.

I know a SCADA software for the PC end which supports MPI protocol for S7-300 series PLC. You can [blue]download software for free with MPI driver and documentation [/blue] at the link:

http://www.icpdas-usa.com/king_view.php

[blue]Luna Li
Application Engineer
www.icpdas-usa.com[/blue]