Analog Track & Hold with do-more!

[Bobby]

Hello all,

Having an issue with how to configure/control Analog Track & Hold with the do-more. I am looking to enable/disable track & hold on WX0. I know back with direcsoft I wrote to a v location but cannot see how to do this on the do-more. I looked at the help file and have attempted writing e003 to WY0 since that is what I gathered from help files but it didnt change it into track and hold.

Hope I explained it good enough  . I also attached a screen shot of my setup. All I want to do is be able to enable/disable track & hold on WX0 only.

Thanks guys!

[b_carlton]

As you have mapped them WY 8-11 are the analog input words. WY 9, 10, 11 are the channel configuration words. WY11 specifically is the word holding the Track and Hold bits.

Search the help file for analog modules and specifically the module you are using (there is a current and a voltage model). Follow the information and assign nicknames to the locations.

[Mike Nash]

As you have mapped them WY 8-11 are the analog input words. WY 9, 10, 11 are the channel configuration words. WY11 specifically is the word holding the Track and Hold bits.

Search the help file for analog modules and specifically the module you are using (there is a current and a voltage model). Follow the information and assign nicknames to the locations.

Well first, this is another of those confusing modules, but I also think you are incorrect on the addresses as his config should have his:

 Analog Inputs at WX0-WX7
 Analog Outputs at WY8-WY11
 Input Resolution Selection at WY12
 Input and Output Range Selection at WY13
 Track and Hold Bits at WY14

So WY14:0 and WY14:1 are the Track and Hold Selectors for WY8 (First Analog Input) You use a combination of the 2 bits to choose your function.

But these are really min or max value grabbers the way it reads. I would use a bit (track) to enable a MOVE instruction from WY8 to D0 say to "track" and hold by dropping the bit out.

I have had to edit these addresses multiple times to get this (hopefully) correct.

(Man, spend a few days on other PLCs and the Do-more is no longer so easy, I hate getting old and porous of memory.)

[b_carlton]

Sorry, I guess numbers were a little difficult this morning. Good catch. It would be interesting if automatic documenting of locations was available.

And I couldn't even think of a way to blame it on decimal versus octal addressing.

[Bobby]

Thank you both for the help. I am actually trying to track a max on WX0 so an input instead of an output. I will attempt the help files again too. Maybe I missed it but I could not find a good explanation of how to control them with do-more.

Thanks,

Bobby Lock

[Bobby]

And I figured it out! Thanks again guys you lead me in the right direction. I didn't realize I had to write a single word into wy14 and that controlled all the inputs depending on the hex configuration!

[Mike Nash]

You can control the bits individually if you prefer. WY14:1 is the bit address for the first channel's "track and hold high value". I think they call this casting. I am still struggling with remembering the terminology.

I also think having these analog modules auto-document would be nice. That was what was throwing me as I was expecting that after using the CTRIO. I might hate it at times though so optional would be cool!

[Bobby]

Hello all again,

I have now switched to the new BRX Analog card and found I am unable to use the track and hold as I did before.. Am I missing something?

[brucek]

I guess they do it automagically but i never new that. I do the hold bit (C0) anded with  a wx0 >= V0 then move to V1 approach. Then when you need to clear just move a 0 to V1. I like to see stuff in the program rather then let the card do the magic and then not be able to see what is not happening, I don't use the scaling to RX0 function because i want to be able to see it in the program for troubleshooting.