adccommunitymod (AutomationDirect) asked a question.
Created Date: February 17,2016
Created By: DuctSoup
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First off, I am *SO* loving these new C0-11ARE-D CLICKs. What an awesome addition to the line. I'm just finishing some lighting controllers and only remembered today that this PLC can also act as a ModbusTCP master. Gave it a try and dang if it didn't work right out of the gate. Noticed one funny thing. In CLICK a zero sometimes shows up as a float that's very near but not quite zero. The slave is reporting holding registers encoded as a standard float. In the CLICK 2.0 software data view a slave value of 0.0 is being displayed as 2.326436E-41, or something like that. If I use Ignition to poll the slave I get 0.0. If I have the CLICK polling the slave then poll the CLICK with Ignition I'm correctly getting 0.0 again. Last time I checked with Modpoll the slave reported 0.0. I totally get that I'm talking about doing floating point math on an economical industrial PLC and this observation isn't a problem for the project I'm finishing. I'm just curious if anyone has any experience or insight to share. Is this behavior coming from the CLICK, or the CLICK software?
Created Date: February 17,2016
Created by: kewakl
Click float is only -3.4028235E+ 38 to 3.4028235E+ 38
So the E-41 may be beating the bounds.
Wait for someone more knowledgeable corrects me.;)
Created Date: February 18,2016
Created by: DuctSoup
Duh, thanks!
Created Date: February 18,2016
Created by: Do-more PE
Correct. Click as well as most PLC's adheres to the IEEE-754 Floating Point standard.
Created Date: February 17,2016
Created by: DuctSoup
First off, I am *SO* loving these new C0-11ARE-D CLICKs. What an awesome addition to the line.
I'm just finishing some lighting controllers and only remembered today that this PLC can also act as a ModbusTCP master. Gave it a try and dang if it didn't work right out of the gate. Noticed one funny thing. In CLICK a zero sometimes shows up as a float that's very near but not quite zero.
The slave is reporting holding registers encoded as a standard float.
In the CLICK 2.0 software data view a slave value of 0.0 is being displayed as 2.326436E-41, or something like that.
If I use Ignition to poll the slave I get 0.0.
If I have the CLICK polling the slave then poll the CLICK with Ignition I'm correctly getting 0.0 again.
Last time I checked with Modpoll the slave reported 0.0.
I totally get that I'm talking about doing floating point math on an economical industrial PLC and this observation isn't a problem for the project I'm finishing. I'm just curious if anyone has any experience or insight to share. Is this behavior coming from the CLICK, or the CLICK software?