Ron_S

Plc type? You need to use the retentive memory area.

The SPD instruction does not work in simulation mode.

Just a point of order MrDippy I had a quick look at your program and I know you threw it together through boredom and to help   But you have put an ALT instruction to change the direction from input X5 Done this way it will be a random ON/OFF as the state will change every scan.  Either X5 should be a rising edge or the instruction should be ALTP   :)    

SFC in step-ladder can be confusing at first as there are things you can do and things you can't. But it's very easy to program a sequence - and easy to fault find as the problem will only be in the active step. Take for instance the drawing below: In STL step 20, you can put an output coil direct from the left vertical bar - but you can't put a timer like that? If you want Y0 to still be on in STL S30, you have to have to program it in again. It ignores the double coil as STL 20 is now not scanned. If you do not put the line -----------------------------------[STL S30} before a step, the S bits will be treat like normal M bits And you mark the end of the STL routine with ------------------------------------[RET]  

Thanks Gambit for the tutorial on sfc. I've never really got on with it....so gave up.   Seeing as I like many have plenty spare time, I wrote a test program for fun and education. Now I understand it a lot better.  

In short, they aren't. The Q doesn't have that function. In the fx, individual steps are defined by a line -----------------[ STL S20] etc (program for s20 here) STL S30 and so on If stl s30 is active, none of the other steps are scanned  

You are not going to be able to convert the stl to a Q Or in fact many instructions.   Stl in the fx is a set of conditional steps where only the active step is scanned.   You would be better with an fx3 or fx5....Or it's a rewrite.

The usb to serial adapters are notorious for failing. First thing I'd check is to use another.

An unusual tale, but in these times of isolation and no work, I'll tell it. A few years back I went to a machine with an FX2n 64 MR controlling  (for want of a better description) a sewing machine. I uploaded the program and saved it before I started on the fault finding. The nice programmer (or so I thought) had saved the comments in the plc too, so it made my job a lot easier. I found the fault - a proxy that lit but gave no output so it turned out a nice easy job with lots of kudos from the customer. I stayed a while and watched this great sewing machine. It had 4 sewing heads that moved in and out of each others space with great timing.   A few years pass with me never going again and they phone me. The transformer has overheated and killed the plc. They have replaced the transformer but the plc was dead. They have also bought a second hand FX2n 64 MR from ebay and swapped that out They thought it was a part you just replaced and everything would be fine.   I explained that the program has to go back in and I might possibly still have it on an old laptop. I searched my files and I did have it, so I set off to another simple job.......not.   I put the basic program back in and it wouldn't work and was doing unusual things. The sewing heads were jumping and solenoids were firing on and off and all manner of things. Looking at the program, there were about 200 data registers (timers, counters, maths etc) But, and I mean but - there was no reference to these data registers apart from where they were in the logic By this I mean, there were no lines like MOV K3 D100. I wrote some dummy logic using MOV's and could see they were all at zero..... The programmer must have punched the values in one by one using 'set device' I could see no reason for this until I realised that because he had used a lot of memory on the comments file, there was hardly any memory left for the program (strange eh) He didn't have the space to put all the MOV instructions or he would lose the comments    Luckily, my routine when first uploading a program is to save it with everything including data values and then re-upload a new copy of the program to work on. I had the data files saved and put them in and all was well.   What a funny way to program.        

Fat chance I'm clicking that.......geddit?

unic0rn Click the default button, FX1n should be 8000   nonito: You have to buy it.

Are you getting any BDTP errors on any screens. When one HMI loses communication, the error shows on the screen. Are the ethernet green lights flickering even when the screen is frozen? Clean the contacts on all the rj45 plugs and sockets.

I came across an FX0n that actually had no wires in the 240V ac power terminals and yet the inputs and outputs were working.??? On further investigation there was a separate 24V dc supply unit that was connected to the 24 and 0v terminals of the plc.  It had worked like this for years. I don't know if the internal 24V dc had failed at some time or it was done from the start - but it worked. Try this method, it will likely spring back to life.

In that case, I would re-install GX developer from scratch too, including Melsoft environment first. maybe some was corrupted.

In GX works use 'change plc type'   It will walk you through the process