Downloading the program from a PLC to a PC

Lou

Member
Join Date
Apr 2004
Location
Montréal
Posts
6
Hi!

Before asking my question, i'd like to put myself in context. I'm a student (I already said it in a previous post, but I'll say it again anyways), currently doing an internship in a moldings factory. I study industrial computer science (real-time programming, communications, artificial vision and robotics, mostly). I had one course on PLC programming, where we used Allen-Bradley PLCs. So to speak, I'm "familiar" with ladder logic, but still quite a rookie, as the field I'm most comfortable with is PC programming.

School offered to find internships for us, but if we found them ourselves we earned extra credits, so that's what i did.

The project I'm working on is fairly simple :I have to reprogram 3 Mitsubishi PLCs so that the data processing is made by a PC. The PLCs are connected to MTA-250 HMIs. All of the PC programming is relatively easy for me, but when it comes to the PLCs and HMIs...

So I've read quite a lot on Mitsubishi PLCs and HMIs (thanks to Panic Mode and Dariusch for extra help), had a list of all the I/O, made my grafcet, now I'm finally ready to start getting my hands dirty... But I can't seem to communicate with my PLC... I connect to it by using the printer/programming port of the HMI (that's what I read in the manuals), but whenever I plug my serial cable, the computer freezes. I've tried both straight and null-modem RS-232 cables, switching the HMI from RUN to PROG and from PROG to RUN, but the computer always freezes.

I'd really appreciate if someone could help me a little, because there's no one in my company to help me (the guy who made the system in the first place was a consultant and just won't come). I guess that's the price for the extra credits...

Thank you all!

Lou
 
Hi Lou,

Make sure the Mitsubishi software version you use is compatible with the operating system of your computer. I have seen this happen on my computer (Win XP pro) in applications that are not WinXP compatible.

Check the communication settings also( Baud rate, address, COM port). That is one common mistake.

Also, did you mean downloading from a PC to PLC?
 
Hi Preeya

I'm using a PII running under Windows 98. What's freezing is not the program itself (it tried to get the program that's inside the HMIs to my computer; I assumed I tried to download it to my PC; I used SW-MTA-WIN 4.20), but windows itself...

What i first did was turning all the power off, then i plugged my PC to the HMI. I turned to power on and booted my PC, but windows never actually started. It only started when I unplugged the cable, and whenever I replugged it, nothing worked anymore.

I've tried all the different configurations that came through my mind (cable, HMI's configuration, HMI programming software configuration), but whatever I do, the computer freezes whenever the cable is plugged. (the keyboard and the mouse stop responding).
 
Lou,

I might be wrong but we see exactly this problem quite often
with all kind of different hardware - when COM port is not
isolated.

I would suggest to try optical RS232 isolation adapters
like the ones from B&B Electronics.
Just scroll ca. two pages down till you see Isolators.
Note that usually only 4 signals are isolated which is often good enough,
but not always, specially with PLCs, HMIs, drives etc.
Depending on what cable you use, you might want to build
adapters to route signals through isolated pins or even
put two isolators.

For PC installed in equipment, we buy special multiport cards
which have all signals isolated. All popular brands like Lava,
Moxa, Rocketport, etc only isolate up to 4 signals of each DB9.
The only fully isolated multiport card I could find was made in
Germany www.meilhaus.com.

Hope this helps...
 
Last edited:
SC09

Lou
Do you have the programming cable for Mitsubishi PLC's (SC09)try to plug it to your serial port and communicate with the plc directly if it works you have no problem with your ports and then you need to check the cables you use to connect to your HMI.Most probably as mentioned above it's short cuircted .
According to my information the cable used for mitsubishi HMI is a standard RS232 you van made by your self. try to make another one and let us know the result.
 
Hi everyone (and a real big Thanks for your support!)

I assumed the COM ports had no shorts since I tried a direct communication using HyperTerminal and my null-modem cable. I don't know if it's a valuable check, so I'm gonna try with another cable, then with all the other hints you guys gave me. It's saturday and the factory is closed, but I'm gonna check all of this first hour on Monday.

And again, I want to thank you all for your help, you can't imagine how much I appreciate it (being in charge of the whole project with no experience or almost is SOOO much harder than I thought it would be, I admire you guys for doing this all the time, it's quite a lot of pressure)

Lou
 
sw-mta-win

lou

where did you find the software sw mta win.
i have a mac12 and realy like to write the programm for it but i can't find the right software for it.
in the manual they speak about the sw mta win software or the dos version.
both i can't find on the internet i hope you can help me



cind regarts

Kees Hiemstra
[email protected]
 
Hi Preeya

I'm using a PII running under Windows 98. What's freezing is not the program itself (it tried to get the program that's inside the HMIs to my computer; I assumed I tried to download it to my PC; I used SW-MTA-WIN 4.20), but windows itself...

What i first did was turning all the power off, then i plugged my PC to the HMI. I turned to power on and booted my PC, but windows never actually started. It only started when I unplugged the cable, and whenever I replugged it, nothing worked anymore.

I've tried all the different configurations that came through my mind (cable, HMI's configuration, HMI programming software configuration), but whatever I do, the computer freezes whenever the cable is plugged. (the keyboard and the mouse stop responding).




hello preeya... from where did u downloaded the software SW-MTA-WIN 4.20 as i have to program Mac 90. do u have any idea about this...
 

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