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
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