Ron_S

glavanov is right - you bought the wrong encoder

Did you read from the eeprom?

I think he meant retentive.

In settings.

Also, if there are no hmi or other devices that can write to that register, the value can be directly entered through the software.

K is a permanent decimal number You need to use a D register in the plc program. Ie C10 D100 Then use D100 in your hmi

Thanks. I don't have the program with me but i'll be going back. I did have a look for indirect addressing but it's a big program. My suspicions are mounting that this is some kind of way to keep outsiders out.   I'll be back with more details later... with this lockdown, they are only working 2 days a week with skeleton staff  

To describe it better, the 12 stations are all one machine on the same common frame. They all do the same job times 12. (Wind yarn into cones to an exact length.) The I/O come into the panel from each station in a multicore and connect to these printed circuit boards. (Inputs to 1set of terminals outputs to another) These pc boards then have 2 plugs connected to the plc I/O (the standard Mitsubishi plugs that connect to the input and output units) There is nothing complicated about this machine. It has buttons, limit switches, valves  and photo cells. And a motor on each station controlled by an inverter that only has 2 inputs (slow and fast), I can't quite remember if there was an error when I tried writing a line, it went grey and when I pressed write, it just stayed grey. I was in monitor write mode.   But the missing I/O in the program baffled me. The inputs came on (led lit) and the machine did what it should but there was no reference in the program To be exact, some inputs outputs were there from each station and I could see them working correctly. I'm open to suggestions as to what these pc boards are doing.      

A strange one yesterday so I am asking if anyone has come across such a thing.   A customer bought a second hand machine and they wanted me to do some minor alterations to the program. It has an A series plc and a beijers e100 hmi (so you can tell it's old) I uploaded the plc program with no trouble.   The machine has 12 identical stations and all the I/O go back to 12 seperate PC boards. These boards then plug into the plc with 12 plugin leads. All the I/O are digital - no analogue. It looks like it is just an interface board but there are some pretty big IC's on these boards.? I monitored the program and couldn't find a lot of the inputs in the program. For instance: Station 1, start button =X1, press the start button X1 input lights up on the plc. X1 does not exist in the program but the station starts The same with them all. When the machine is totally stopped, lots of inputs and outputs are flashing on and off at a rapid rate. If I try alter anything it just won't write to the plc The machine works perfectly, it's not lose wires or anything.   UGH??        

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