Real MOV in CJ1

[Riggs 0]

Hello All, I've got a real number (x_REAL) which I want to fix into an INT (x_INT). If the value of x_REAL is above 32768 or below -32767 I want to limit it to those values. I am trying to do this with a couple of compare instructions followed by MOVF instructions: >=F x_REAL +32768 which turns on a MOVF +32768 x_REAL instruction and <=F x_REAL -32767 which turns on a MOVF -32768 x_REAL instruction Then a FIX x_REAL x_INT instruction. BUT: the CJ1 dosen't support MOVF, and I cant see another way to assign a value to a real on a CJ1. Am I missing something really obvious here? Any help would be much appreciated! James. (P.S. I'm on a bit of a steep learning curve here, so will probably be asking a few stupid questions over the next few weeks... and I'm spending a lot of time poring over the manuals, before anyone asks!) Edited 4 Sep 2009 by Riggs

[dweste 0]

I suppose you want to go up to +32767, thats the maximum for a 16-bit signed integer? Instead of 'MOVF +32767 x_REAL' you can use 'FLT +32767 x_REAL'. Instead of 'MOVF -32768 x_REAL' you can use 'FLT -32768 x_REAL'. Edited 4 Sep 2009 by dweste

[banker 2]

Hi Real format is 32 bit you can use MOVL Move long. But in you case you need to use a Convert instruction FIX. Real to 16 bit. Use CXP instruction help. Banker

[Riggs 0]

Aha, thanks for that dweste, I hadn't spotted the FLT instruction. And yes, I do mean 32767. Banker, I realise that this has been covered over and over again in the forums, but I was under the impression that if you MOV a 16 bit integer into a 32 bit real, then the PLC will interpret the real number incorrectly? I've rejigged the program now to use FIX, and if the FIX turns the error flag on, I then do the comparisons and use FIX to load the 32767's into the x_INT register. Thanks for your excellent replies, James. Edited 4 Sep 2009 by Riggs