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Author Topic: DL405 - What is the addressing scheme for analog inputs and outputs?  (Read 4194 times)

wildcatherder

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I've been working with discrete inputs and outputs and now have to use analog.  I have looked EVERYWHERE and cannot find the answer to this simple question.

What are the memory addresses for the analog inputs for a 16-point module (D4-16ND2F) in the first (leftmost) slot of a DL405?

I find information that addresses in the first slot begin at V40400 but it is not clear how much address space each input requires.
I have seen examples that show an 8-point analog current module using only eight addresses and referred to as X0 through X7.

How can X0 be the same address for a 1-bit digital input OR a 12-bit analog input?

I also find references to "pointer method".  I know what pointers are but I cannot find an explicit definition of how this applies to DirectSoft5 programming.

I found the Analog_IBox_Help_Example.PRJ but it starts with using ANLGIN Analog Input Module Pointer Setup which does not appear on the list of available IBoxes for my version of DirectSoft5 v5.3.

Please help.

b_carlton

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Re: DL405 - What is the addressing scheme for analog inputs and outputs?
« Reply #1 on: August 28, 2009, 02:04:59 PM »
D4-16ND2F is NOT an analog input card. It is a 16 point DC discrete input card.
An output is a PLC's way of getting its inputs to change.

MikeS

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Re: DL405 - What is the addressing scheme for analog inputs and outputs?
« Reply #2 on: August 28, 2009, 02:28:09 PM »
essentially what is happening is that the analog modules multiplex all of their channels into one 16-bit register. So the PLC needs ladder logic to read this one location and de-multiplex it into the PLC's v-memory. you'll find the appropriate ladder logic for each module in the analog i/o user manual, there's a chapter devoted to each analog module (by part number).

the ibox you referred to is only available for the DL205 series PLCs, not the dl405 series. so it's not a limitation of DSOFT v5.3, it's just not appropriate for your particular PLC.
Good design costs a lot. Bad design costs even more.