11 replies to this topic

[Superkalle]

Hi

A friend at work has this idea to use Mindstorms/LEGO to visualize MES (Manufacturing Execusion Systems). So I was wondering if anyone here knows cases where Mindstorms units have ever been controlled by an industrial PLC, like Siemens Simatic/S7 or similar. Or does anyone have some good examples of LEGO/Mindstorms used to illustrate industrial MES-concepts.

[DLuders]

National Instruments' LabVIEW software is used in both Lego Mindstorms and industrial Programmable Logic Controllers (PLCs): http://www.ni.com/labview/ .  In the "Search" box, I typed in "PLC" and "Mindstorms" and got a whole bunch of "hits."  Here's a video of a German instructor who, with his students, made a Lego Aircraft Factory that could assemble a Lego airplane using 25 Mindstorms controllers: http://decibel.ni.co...ircraft-factory .

[Superkalle]

Thanks dluders. Have you had any own experience in this field, or did you google it?

[DLuders]

No, I don't have any experience in PLCs or using National Instrument's LabVIEW software.  I'm sure that SOMEBODY out there has done more -- one just has to go down further on the Google pages!  

[Superkalle]

Well, googled I have, thus this topic  

So, the question is still open

[DLuders]

From an article posted two weeks ago on http://www.controlgl...s/2010/126.html :

"Connect to Any PLC using NI LabVIEW
ControlGlobal.com
06/17/2010

By National Instruments

Add advanced analysis and control functionality—available through National Instruments' LabVIEW software and programmable automation controllers—to any PLC using the new NI OPC servers. View this webcast to learn how to create tags in OPC servers and utilize OPC client connectivity to communicate between NI LabVIEW and PLCs."

Lego Mindstorms NXT uses LabVIEW, PLCs can use LabVIEW, hence NXT can be programmed like PLCs.  

[Superkalle]

dluders, on 05 July 2010 - 04:37 PM, said:

From an article posted two weeks ago on http://www.controlgl...s/2010/126.html :
Lego Mindstorms NXT uses LabVIEW, PLCs can use LabVIEW, hence NXT can be programmed like PLCs.  

Like I said. I have done all the googling needed and I have seen that article before. Mayve I was unclear in my first post, but my quesiton was here if anyone has practical experience or personal knowledge, or knew if any company or university had actually done anything in this area. Thanks anyway dluders!

[roamingstudio]

Practical experience in Labview = Yes
Practical experience in connecting NXT to PLC = No (sorry).

I would look at the website for the Control Laboratory (RWTH) at the University of Aachen - they developed the Matlab NXT toolboxes - and may know others working in this area.
http://www.mindstorms.rwth-aachen.de/

Option 1: if you want direct integration then you are perhaps thinking of running a converter cable into the inputs / outputs. Since these run on the I2C format it might be possible to find a converter to the PLC... (A quick google search was not looking positive).

Option 2: Control the NXT via the serial interface (USB cable/ bluetooth). I have used the Matlab toolbox from RWTH which communicates with a small firmware module downloaded to the NXT memory. This interface is a simple serial protocol - and with a small embedded PLC it should be possible to send and receive sensor port data in semi-realtime. It is not perfect; (i.e. uses a polling loop to monitor motor positions, so has overshoot) but could provide a quick and dirty hack. There might be other alternative firmware - but this was the most practical / open one (http://en.wikipedia....dstorms_NXT_2.0)

Feel free to send me a PM if I can be of more help.

[Superkalle]

Thanks so much roamingstudio   . I'll take this info to my workmate, and see what he says. However, now it's summer vacation, so it'll probably be in August.

[Silcantar]

I've used NXT with LabView, if that's what you're looking for.  I'm not sure how much help I can be, I found it to be rather frustrating.  I'm new to both LabView and NXT, although I do have two Robotics Invention Systems.  Someone with more LabView experience might find it less frustrating and be more helpful.

[ronmcrae]

roamingstudio, on 05 July 2010 - 06:33 PM, said:

if you want direct integration then you are perhaps thinking of running a converter cable into the inputs / outputs. Since these run on the I2C format it might be possible to find a converter to the PLC...

So far I don't see anyone mentioning the very much underused and under-publicized RS485 serial interface on NXT input port 4.  That allows the NXT to interact directly with any PLC that supports Modbus-ASCII, which typically runs on a 2-wire daisychained serial link.  All that you would need is Modbus drivers (i.e. software) for the NXT.

Some months ago I played with some NXC code on the NXT to have it receive Modbus data packets and generate a response.  I definitely proved the concept, but never did complete the project due to other things coming up.

Ron.

[roamingstudio]

ronmcrae, on 16 July 2010 - 08:05 PM, said:

So far I don't see anyone mentioning the very much underused and under-publicized RS485 serial interface on NXT input port 4.  That allows the NXT to interact directly with any PLC that supports Modbus-ASCII, which typically runs on a 2-wire daisychained serial link.  All that you would need is Modbus drivers (i.e. software) for the NXT.

Did not know there was an RS485 on there. Now that is a neat... but the NXT protocol would need to be written. Damn I wish I had more hack-time... ;-) Currently my head is full of Quaternion theory.