Host Engineering Forum
General Category => DirectSOFT => Topic started by: wildcatherder on August 28, 2009, 01:33:21 PM
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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.
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D4-16ND2F is NOT an analog input card. It is a 16 point DC discrete input card.
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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.