String Data

[RheinhardtP27 0]

Hi All, Im a Siemens programmer being thrown into the wonderfull world of GX Develper IEC. I have some question... I need to move and copy a string within the PLC , actually the idea i to create a buffer area with 2 fields. Ex. String1 String2 XXXXXXXXXXXXXXXXXXXXXXXXXXXX 2384756 Question 1 How can i move the complete string typically i would have used BLOKM in the siemens. Question 2 How can one compare a string in the IEC software. Any guidance assistance will help. Rheinhardt

[kaare_t 155]

What PLC do you have?

[RheinhardtP27 0]

Sorry i forgot to mention, i use the FX3u series PLC.I also use the GX Developr IEC version of the software for the FX series. The idea is to connect the unit to a barcode scanner and to then compare the data out of a buffer. Once i have compared and found the data i delete it and shift my buffer. Many Thanks Rheinhardt Edited 16 Mar 2011 by RheinhardtP27

[plcdp 11]

Hello, Look up the instruction BMOV. It is a block move that I think should be similar to the Siemens instruction. plcdp

[kaare_t 155]

Q1: Instruction "STRING_MOV_M" Q2: Comparing strings is a bit more difficult. You'll have to convert the strings to words and compare them. To convert from string to word use the BMOV_E or BMOV_M instructions....

[kaare_t 155]

plcdp beat me to it

[Inntele 60]

The FX3U supports special instructions which work with string variable (FNC 200-209). I think you can use VAL instuction for conversion String to BIN and then use BKCMP function for comparision of two data block. If I'm wrong, please correct me colleagues

[RheinhardtP27 0]

Thank you for your prompt replies. I will do some testing and revert back to the forum. RP

[RheinhardtP27 0]

Hi Gents, I have done some testing and have a problem. What is the maximum allowed String lenth in the GX Devloper IEC Global variable definition. I have a string which is 17 characters, when i try and move data using the String_MoV_M instruction only 16 characters get transferred. Is the limitation in the definition of the string or the String_Mov_M funtion. Has anyone managed to move large amount of characters. Rheinhardt Edited 21 Mar 2011 by RheinhardtP27

[kaare_t 155]

See here (one thread is enough ): http://forums.mrplc....=0&gopid=101952&

[RheinhardtP27 0]

Thank you Kaare