Peter Nachtwey
Member
What a nightmare. It rates right up there with S7s. The only thing I did like is that I could enter a block where I could enter a ST block in the middle of the ladder programming. This allowed me to simply write code instead of mickey mousing around with my hand going between the keyboard and mouse. The ST blocks are like our expression/compute blocks in our motion controller.
Connecting with GX2: I used a USB cable at first. This was simple and worked flawlessly. However, when I used Ethernet it would only work for a few minutes and stop. I went back to using the USB cable. I should have stopped right there and handed the PLC back to Jacob.
I started by making an example program with nested FBs. They were easy enough. One thing I didn't like as there was no obvious RUN/STOP keys or buttons.
Help: There is lots of it but it isn't very clear. What I didn't like is that the help is spread around in many files so you must manually search for the right PDF. They should have one complied help file with lots of cross indexing like we do. Also, some of the documentation was for ST, some for LD and some for IL. The On-line help for instructions was good though.
HMI: It is fairly typical. What I didn't like was the editing. I had to move my hand from the keyboard to the mouse all the time. Here Rockwell wins big. I like the fact I can enter ladder in text on one line. Also, if I used long names the boxes wouldn't fit across the page and I would get errors instead of the HMI moving the boxes for me so they would fit. GX2 has intellisense but it would display only the first few characters of the variables even though it could have easily displayed more. To make sure I had the right variable I had to hover on a possible variable until the whole name was displayed.
Features: At first I was very impressed that one can have arrays and structures. I made some structures for the Ethernet headers so it would be easier to tell which data was from which layer in the Ethernet. What I found out is that I couldn't reference the arrays or structures from the SP.xxxxxx type socket functions that I trying to use. I couldn't make a one register alias for the first word in the structure or array that I could use either. The BMOV function would accept an array as the source and destination.
My goal was to write a FB that would function like a Rockwell MSG block except I would have one for read and one for write. This is where things got bad. After fighting with the system for a few days to make the read function block I activated the read function block and the first thing it did was to stop the PLC when it tried to open the socket. The ladder compiled correctly but the CPU still faulted. The error message said something about my PLC may not be supported but my PLC was the right kind with the right serial number.
Perhaps I can't sockets in a FB. I don't know. The error messages were often misleading.
Conclusion: GX2 Developer is painful to use compared to Microsoft Visual Studio,NetBeans, CodeWarrior or CodeComposer. The fact that Mitsubishi has an Ethernet port does not mean it is functional. The pain and agony to get the Ethernet to do what a message block is too great. The time I wasted on this PLC was worth more than the PLC easily. The GX2 and PLC are a little more transparent than the Step7 and S7 but functionally neither are nice to use.
A PLC should have something equivalent to the Rockwell MSG blocks before it can say it has Ethernet capability. Socket level functions don't hack it. It takes too much code. Sockets are easy enough in C though. This is kind of like a lot of motion controllers that claim to have auto tuning but it really isn't functional.
One should be able to program without having to use a mouse. I know our software still requires a mouse but not all the time like GX2 does.
Connecting with GX2: I used a USB cable at first. This was simple and worked flawlessly. However, when I used Ethernet it would only work for a few minutes and stop. I went back to using the USB cable. I should have stopped right there and handed the PLC back to Jacob.
I started by making an example program with nested FBs. They were easy enough. One thing I didn't like as there was no obvious RUN/STOP keys or buttons.
Help: There is lots of it but it isn't very clear. What I didn't like is that the help is spread around in many files so you must manually search for the right PDF. They should have one complied help file with lots of cross indexing like we do. Also, some of the documentation was for ST, some for LD and some for IL. The On-line help for instructions was good though.
HMI: It is fairly typical. What I didn't like was the editing. I had to move my hand from the keyboard to the mouse all the time. Here Rockwell wins big. I like the fact I can enter ladder in text on one line. Also, if I used long names the boxes wouldn't fit across the page and I would get errors instead of the HMI moving the boxes for me so they would fit. GX2 has intellisense but it would display only the first few characters of the variables even though it could have easily displayed more. To make sure I had the right variable I had to hover on a possible variable until the whole name was displayed.
Features: At first I was very impressed that one can have arrays and structures. I made some structures for the Ethernet headers so it would be easier to tell which data was from which layer in the Ethernet. What I found out is that I couldn't reference the arrays or structures from the SP.xxxxxx type socket functions that I trying to use. I couldn't make a one register alias for the first word in the structure or array that I could use either. The BMOV function would accept an array as the source and destination.
My goal was to write a FB that would function like a Rockwell MSG block except I would have one for read and one for write. This is where things got bad. After fighting with the system for a few days to make the read function block I activated the read function block and the first thing it did was to stop the PLC when it tried to open the socket. The ladder compiled correctly but the CPU still faulted. The error message said something about my PLC may not be supported but my PLC was the right kind with the right serial number.
Perhaps I can't sockets in a FB. I don't know. The error messages were often misleading.
Conclusion: GX2 Developer is painful to use compared to Microsoft Visual Studio,NetBeans, CodeWarrior or CodeComposer. The fact that Mitsubishi has an Ethernet port does not mean it is functional. The pain and agony to get the Ethernet to do what a message block is too great. The time I wasted on this PLC was worth more than the PLC easily. The GX2 and PLC are a little more transparent than the Step7 and S7 but functionally neither are nice to use.
A PLC should have something equivalent to the Rockwell MSG blocks before it can say it has Ethernet capability. Socket level functions don't hack it. It takes too much code. Sockets are easy enough in C though. This is kind of like a lot of motion controllers that claim to have auto tuning but it really isn't functional.
One should be able to program without having to use a mouse. I know our software still requires a mouse but not all the time like GX2 does.
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