Luke.S

I don't know if it's still of interest to the OP or anyone else but I was looking up an instruction in the FX5U programming manual today and noticed that instructions now do have an unsigned version. It even has a nice explanation of overflows as was described above. I suppose it's the same on the iQ-R too to bring it inline with other vendors. As far as I'm aware it is not possible to specify unsigned on the Q or FX3 series. I was just surprised by the way the tool dictated the programmer's use of the register by not allowing integer representations over 32,767. Surely that's our call!?  

Great link Akahige. Wish I'd known about this when I first started using Mitsubishi. Would've saved me a lot of reading!

When the card is plugged into the bus you then need to check the XY assignment. The start I/O No. of the card needs to match up with place the card is on the bus. The XY assignment is divided into channels of 16bits e.g. 10 is channel 1 (x10~x1f), 20 is ch2 (x20~2f) etc. Some modules take 2 channels, some 1. Check the XY assignment in PC Parameters or just count to what channel card is on. That will tell you where the new Xs and Ys are. For a standard I/O card you can then just start using them in the program. You can check the I/O limit by looking the memory assignment in PLC parameters or going to Global Device Comments and seeing how long the table is for X and Y labels. Maybe around 8000 points on an FX3. Another thing to watch out for is that you don't exceed the power rating that the PLC has for the bus. Google the "FX3U Users Manual (Hardware)" and have a good read through that.

Yes in the purest sense when the bits go to the adder transistor circuit on the chip it will change the requisite bits in the bit pattern accordingly. But on the PLC  programming level to pass what the user interprets as an "unsigned int" to a program with single word commands could cause chaos. It's really interesting to think about this because (obviously I hope) you always program to make sure overflows can never happen. I didn't know that the programming tool displays the value of the register depending on what instruction it is being used with. Of course with the HMI you tell it how to display the contents of the register.

It definitely handles arithmetic operations as signed. Interestingly, it won`t even let you input a K larger than 32,767 into a single word instruction. Idiot proof but not programmer proof :)

I've always seen it that way too. You can do a block compare on a bunch of registers and it makes no difference to the PLC if they are signed, unsigned, float whatever, all the PLC sees is a bit pattern. Whether the sign bit is 1 or 0 only affects how the bit pattern is interpreted by certain instructions and devices such as HMIs. This must be interpreted by ADD instructions too because you can ADD a "negative" value to another int with the net result being a subtraction. I suppose if you SUB 65,535 from k0 you just go back to 0.

You can copy ladder logic program files, ST, FBs etc. and their local labels by right clicking on them in the navigation tree. Then just paste them into the other project's tree and set them to be scanned.  It probably won't be that simple though. This is assuming that the different program units operate independently though and don't clash on outputs etc.

Hi. Do you mean the bit you use to reset the user alarm display on a GOT HMI? You should be able to assign multiple functions to a push button. In the create push button dialogue on the left you can make a list of them. Function 1 would be set the alarm reset bit and function 2 would be "move to base screen x." You might need to write a handshake sequence with the HMI alarm reset bit because it doesn't always respond if the button was pressed very quickly.

I really understand where you're coming from with the Mitsubishi manuals. It feels like the information you need is dispersed across 10 documents, sometimes the programming examples don't work and don't explain how to actually input the command. The Q series network setup is under Parameter, Network Parameters in the navigation tree. If you go into to the CC IE tab, you can set the network settings as per your requirements. The start I/O No. needs to match up with where your network card actually sits on the base unit (your XY assignment).   The XY assignment is divided into channels of 16bits e.g. 10 is channel 1 (x10~x1f), 20 is ch2 (x20~2f) etc. Some modules take 2 channels, some 1. It should tell you that in the manual (if you can find where hehe). If you haven't already, set up your XY assignment in PC Parameters. You can check it with the "Acknowledge XY Assignment" button. See where the CC Link fits in and set its start I/O no. If the network is setup correctly you should be able to access the remote devices via buffer memory with FROM/TO commands. Or you can set up the "Refresh Parameters" to assign them to a memory location automatically.