adccommunitymod (AutomationDirect) asked a question.
Created Date: September 17,2007
Created By: 72hdflh
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This is my first analog project and I am learning as I go, So please forgive me if this is a stupid question. I have an analog infrared temperature sensor that is 0-10 vdc, I have the sensor scaled so that at 110 deg. F, I have 10 vdc and at 140 deg. F, I have zero vdc. With a 30 deg. span I divide 4095 by 30 I should have a value of 136.5 per deg.(Example;110 deg=4095,111 deg=3958,etc.) How can I use this data to view the actual temperature on my C-more HMI. Right now my raw value is in V 2001 and my filtered value is in V 2011, also this is a DL06 plc. I tried the ANSCL i-box with High Engineering set at 110 and Low Engineering set at 140, this worked O.K. at 4095 and 0 but the in between values do not come out right. Any help will be greatly appreciated. http://forum1.automationdirect.com/board/confused.gif
Created Date: September 17,2007
Created by: KPrice
Is this correct?
0-10VDC input signal
0-4095 raw value
110.0 deg @ 10VDC
140.0 deg @ 0VDC
You want 1-decimal point temp
You are using BCD
Your equation could be:
temp (xxx.x)=1400-((raw value*300)/4095)
I included the correction for 1-decimal point. This could be into a BCD math I-box.
Using standard instructions, your code could be:
LD raw value
MUL K30
MUL K10
DIV K4095
OUT mx value
LD K140
MUL K10
SUB mx value
OUT Temp (xxx.x)
I used seperate instructions to correct for the 1-decimal point. I have not yet tried the ANSCL i-box. I do not know if the ANSCL i-box can handle the neg slope. You could then display the temp (BCD) on the C-more showing the 1-decimal point. Does this work for you?
Created Date: September 17,2007
Created by: 72hdflh
KPrice,
Yes, This info is correct.
0-10VDC input signal
0-4095 raw value
110.0 deg @ 10VDC
140.0 deg @ 0VDC
You want 1-decimal point temp
You are using BCD
The code that you posted works but only in reverse with a value of 4095 I am reading 139.4, if I drop the decimal I get 140.
Thanks for the help.
I should also add 10VDC = 4095
Created Date: September 17,2007
Created by: KPrice
I assume (which gets me in trouble) that you have the sensor connected, the PLC is in RUN, and you 're monitoring the (2) v-memory locations in a Data View? You see "4095 " in the "raw value " v-memory location, and "1394 " in the "Temp (xxx.x) " v-memory location? Could there be any other lines of code that are writing to the (3) v-memory locations "raw value ", "mx value ", or "Temp (xxx.x) "? Also, I'm curious that the senor seems to be going full-scale or out-of-range. Could there be a problem causing the signal to go out-of-range? Do you ever get the "raw value " to be, say, 3/4 range (3071)?
Created Date: September 17,2007
Created by: 72hdflh
KPrice,
"I assume (which gets me in trouble) that you have the sensor connected, the PLC is in RUN "
Yes
"You see "4095 " in the "raw value " v-memory location, and "1394 " in the "Temp (xxx.x) " v-memory location? "
Yes
"Could there be any other lines of code that are writing to the (3) v-memory locations "raw value ", "mx value ", or "Temp (xxx.x) "? "
I don't think so?
I am at full scale at 110 degrees F or less, I am not sure if it maybe going out of range, if it is I never see it go past 4095 in the Data View. I am testing it with a flame, which with scaling in the sensor that I have (110-140 degrees) it is pretty much 4095 to 0, but even with the flame in front of the sensor I never see 0 in Data View,it only goes to about 5, so I am not seeing anything in between. I am going to try to email you a pdf of my short little piece of code and a screenshot of Data View.
Thanks for your help.
Created Date: September 17,2007
Created by: KPrice
I received your email and attachments. And I will review.
Created Date: September 17,2007
Created by: KPrice
I will send you an email with some more detail. But for the purposes of this forum, I found that the V-memory location that was used for the "mx value " was also used by one of your unused analog input points and was being over-written by the unused analog input point value. The small value (caused by noise on the open connections) caused the miscalculation.
Created Date: September 18,2007
Created by: 72hdflh
I replaced V2003 with V2011, with a value of 4095 in V2001 I am getting a value of 6 in V2011 in Data View. In C-more with a value of 4095 in V2001 I am still reading 139.4 and when I put the flame in front of the sensor I will get a value of 5 in V2001 and C-more is showing 140.0.
The code that I have for the analog out seems to work as far as giving me 4-20ma out, verified with my VOM. It looks like my biggest problem is getting the readout on the C-more to display properly.
Created Date: September 21,2007
Created by: 72hdflh
I got it solved by eliminating the MUL K10 and changing the MUL K30 to MUL K300. Works perfectly now.
Thanks
Created Date: September 21,2007
Created by: Bob S BN
to: 72hdflh
Do you still have the round tube swingarm with drum brake or did you switch to rect. tube and a gma disk setup??
Yes, I rode one for 10 years.
Good luck with your project, Bob
Created Date: September 21,2007
Created by: 72hdflh
To Bob S BN
When I got the bike the Drum was in bad shape so I changed to the rectangular swingarm and I used the stock style banana caliper.
Thanks
Joe