Panasonic FPWIN FP2 DT values

[Riteway]

Can someone tell me what I'm seeing here? I'm online with the FP2 and looking at some rungs with DT120 and DT124. Each are used twice and each have a live value, but the live value is different for the two DT120's and the two DT124's...? How is this possible? How can DT120 be 33554569 and 137 at the same time? I've attached a screenshot if that helps.
Thanks in advance for any help!

 

[parky]

Never done Panasonic but some instructions are very similar to Mitsubishi,
At a guess a DMOV is 32 bit move instruction, however, the WRT may be a 16 bit instruction hence the "K" constant so when evaluating for monitoring purposes DT120 is actually DT120 & DT121 (two 16 bit registers, not looked at the values but assume any value below 32767 will only show up in DT121 so DT120 would be 0, values above this would show a small number in DT120
So as the rung is not evaluated it looks like as the second DT120 value is reading only DT120 as a 16 bit value whereas the first instruction is reading as a 32 bit value.
So as DT120 as a 32 bit number with a value of 1,362,582 would be
DT120 as 0000 0000 0001 0100 & D121 as 1100 1010 1001 0110
So as I assume the WRT function is 16 bit (I would expect a 32 bit to be DWRT)
so it is evaluating DT120 as Decimal 20 in the second rung although by the looks of it the rung is not being processed as R701 is not on.

 

[parky]

Just tried it on Mitsubishi & it does appear to tie in with what I explained.
Below is some code where I put your value into D120 & D121 (32 bit)
& also see the status of just D120 as a 16 bit word.

 

[Riteway]

Thank you Parky!! I've been in this program for 8 hrs today. Never used this software and finding more questions than answers. My eyes are about bugged out. I now have 1 answer!
Much appreciated, makes perfect sense, kind of feel a little dense for not thinking of that on my own. LOL Again, Thank you!!

 

[parky]

Seems to me that this is bad practice to zero only the top end of a 32 bit Dint, perhaps there is some reason we do not know of but unlikely, perhaps the original programmer has simply made a mistake by using a 16 bit instruction when it should have been a 32 bit, whatever the reason many people would not realise why this is happening so don't beat yourself up.

 

[drbitboy]

Looking at the manual (cf. attached pages; found via The Google), the WRT instruction is roughly analogous to COPy in other PLCs, reading data from a CPU starting at a register (DT120), but writing to an address in the shared memory of an "intelligent unit" (whatever that is).

So the preceding DMV (Double MoVe) is used to load two 16-bit words (0x0200 and 0x0089), which is probably why a hexadecimal constant is used, i.e. so it is be easier to grok the individual words when browsing the code.

The WRT command

• copies those two words (K2; third parameter),
• starting at DT120 (second parameter; 16-bit address) in CPU memory,
• to address 256 (H100 = 0x100; last parameter)
• of the intelligent unit in slot 0, bank 0 (H0; first parameter).

It is the convention of that second [F151 WRT] parameter, D120 in this case, being a 16-bit register that makes it display 137 (0x0089) instead of the full 32 bits being transferred.

Mystery solved, but I gotta get a life .

 

[parky]

@DR: Yes I believe you are right, I imagine the WRT instruction is equivelent to Mitsubishi TO instruction the instructions FROM & TO are used to send data to & from special cards I imagine that the WRT function & probably the RD function in other words write & read.
In Mitsubishi a [TO K0 D120 Kxx] is the same I suspect it is probably an analogue card to set up some parameters.

 

[Riteway]

You are correct! This is writing to a Servo Control Card, PP42 passing parameters to Mitsubishi amplifiers in one machine and Panasonic in the other.

Thank you all again!!!!