FX series indexing problem

[M1923 0]

Hi ,everyone: why can't FX series PLC use index registers in structure program except FX3U/3UC ? Is structure program not designed for those outdated PLC? Can anyone tell me why? thanks in advance.

[Sergei Troizky 26]

The set of supported addressing methods is the property of the PLC, and does not depend on programming language or software used. FX series below FX3 does not support indexed addressing for bits.

[Inntele 60]

but support the indexing a group of bits. So the aim can be achieved by following sequence of command: LD TRUE MOV K1M233Z K1M35 LD M35 ( both and M36, M37, M38) ... Because MOV command can copy not only four bits, but up to 16 bits (with DMOV up to 32 bits can be copied) a programmer can copy the quantity of bits that he need and then use direct addressing for each bit of those copied. Edited 16 Aug 2013 by Inntele

[M1923 0]

Thank you for your answer, Mr Troizky . I made a mistake. The FX series PLC dose support indexing instruction in structure language as you say, but I just can't monitor structure program containing Z/V device neither online, nor offline. When I do so , a message “the device which can't be monitored is used" is displayed. I have tried to reinstall the GX WORK2, but it dosen't work.

[M1923 0]

but support the indexing a group of bits. So the aim can be achieved by following sequence of command: LD TRUE MOV K1M233Z K1M35 LD M35 ( both and M36, M37, M38) ... Because MOV command can copy not only four bits, but up to 16 bits (with DMOV up to 32 bits can be copied) a programmer can copy the quantity of bits that he need and then use direct addressing for each bit of those copied.

[kaare_t 155]

You can "never" monitor indexed bits since the software cannot know the value of the index register, and hence cannot know which bit to monitor in the GUI.

[M1923 0]

It's indexed data register I want to monitor. It can be done in simple ladder, but not in structured ladder.

[Crossbow 297]

There is a limit on some older FX products of one index, so Z not Z1. Check the manual for the PLC to see how many exist for your CPU. Also, there are some limitations to structured projects in the FX series, all of which are in the manual for the FX structured programming.