NEWBIE Q Ethernet/PLC platform/PC conectivity

[eric14779]

also posted on the Automation Customer Forum...



I looked at a proposed project yesterday that the customer wants to retrofit a old, old Motion control system (uses a phone modem for remote login)

this machine is dedicated to punch up to 8 different types of holes and slots along a length of roll formed steel or aluminum strip.

Each different part is assigned a contract #, Program #, and a description.

they enter in the "punch number" , the distance to the first "hit" from (zero), the quantity of hits per part, and the Pitch between. for each punch # that is used to process the workpiece.

The list of different punch hits is then calculated and sorted by the existing control, So that the workpiece can be pulled thru the punch "gang" in one pass and exit the machine done.

The workpiece is gripped and released as necessary to index down the length of the workpiece. But the workpiece only moves in one direction from one end to the other... and out..

My thinking is that this can be done with a modern PLC as well.

can I read in a speadsheet file with the required data in some set format from a Ethernet network off a PC acting as a server, or enter the data at the control.

After loading the data can I calculate and sort the required holes from the starting end to the finish end and come up with a motion plan for the part and drive a servo motor to index the workpiece and also fire the proper punch solenoid to put the punched features in the proper locations.

There will be a multitude of parts so a "recipe" type setup is not efficient... the control MUST be able to look at the list of holes and punch outs and calculate how to process the workpiece in one pass.

I am not sure what platform would be best to do this...

Again I would need Ethernet connectivity for loading and backup of data

ability to load data off a PC spreadsheet

ability to calculate total number of holes and locations and sort from the start end to the finish end.

then drive a servo motor and fire the 8 different punches in time.

[Controls Guy]

A modern PLC is certainly capable of handling the punching and indexing operation, but most current PLC's would have trouble extracting the data from a spreadsheet residing on a PC on the Ethernet network with the PLC.  I think you'll need a program running on a PC, either one you write in total or one based on a commercially available HMI (Human Machine Interface) software package.  That package could also be the operator interface for the machine.  The program would get the information from the spreadsheet, probably do the sorting as well since that sort of thing is easier in a PC than a PLC, create a one-off "recipe", and download it to the PLC either in total or one step at a time.  I would probably transfer the instructions for one part complete all at one time.

[eric14779]

Thanks Controls Guy,

  That is what I am starting to believe....  Do I need to use a WinPLC CPU to integrate the PC to the PLC ?   

[Controls Guy]

I wouldn't recommend it.  Get a PLC and program it to do the indexing, punching, material handling, labeling, etc. and get a PC, either an office type or an industrial type with a touchscreen, and get an OTS HMI package like InTouch or Lookout Direct or whip something up yourself in VB or something.  There's a company called Azeotech (http://www.azeotech.com) that makes an good, inexpensive HMI called DAQ Factory that includes scripting capability.