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display REAL on HMI

Created by: mrfusion at: 7/4/2014 1:23 PM (6 Replies)

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7/4/2014 1:23 PM	Rate (1)
mrfusion Member Joined: 6/26/2014 Last visit: 1/13/2020 Posts: 13 Rating: (1)	Hi, I am trying to display a REAL number from an S7300 PLC to an HMI screen What I have is either a value in a DB or on tags (i've tried both) in the format REAL of a value of 1.2-e008 I create a display field on my HMI and link the input to the DB via the value name e.g DB.A1_REAL That all connects ok. In the proerties of thedisplay field I set the display field type as 'decimal' and set the digits as 9.99e however the output is 0.00e00. But the value in the PLC is greater than zero when monitored. I have noticed that when the REAL number is 0.012 i.e. e-2 if I set the display digits as 9.9e what the HMI actuall shows is 1.0-e2. The '2' is missing even though I defined a digit for it. IF I set the display digits as 9.99e what I see on the HMI is 1.20e-2 however the last zero will never be used. My REAL numbers are generate using a String-2-Real function and that works fine and I can seethe REAL numbers echo the same value as what the input string shows, in real time. So I am a bit lost as to why this is not working. Does the HMI REAL expect 9.9e99 and I am inputing 9.9e999 i.e. 1.2e-008 ? thanks for any help.

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7/4/2014 10:53 PM	Rate (0)
William_B Posts: 5225 Rating: (1198)	Hi there. To make sure we are talking of th same thing, a JPEG file is attached it to this message. A KTP600 panel is used in the example JPEG. The format pattern you specify in the IO field properties, sets a fixed decimal pattern. The panel does not show scientific notation as you see in the Step7 environment. If the pattern is set to "s9.99".. 1.2 >> 1.20 1.23 >> 1.23 1.234 >> 1.23 1.235 >> 1.24 12.34 >> #### (can not display) 0.004 >> 0.00 (TIA: 4.0E-3) You could change the background of the displayed REAL with animation properties; maybe make it red if the value is bigger than 1E-20 but smaller than 1E-2. If it is important for you to display the EXACT number, regardless of what that number is, I would suggest you make your own scientific notation display. Using the definition for REAL you could design coding to decontruct a REAL number into the BASE and MANTISSA components. TIA help file description for REAL Sign: The sign is determined by the signal state of bit 31. The bit 31 assume the value "0" (positive) or "1" (negative). 8-bit exponents to basis 2: The exponent is increased by a constant (base, +127), so that it has a value range of 0 to 255. 23-bit mantissa: Only the fraction part of the mantissa is shown. The integer part of the mantissa is always 1 with normalized floating-point numbers and is not stored. If I have misunderstood your problem.. please tell me where I have gone wrong. Greetings. w Attachment Visual clue_format pattern to view REAL number.jpg (1342 Downloads)
William_B Posts: 5225 Rating: (1198)	Last edited by: William B. at: 7/4/2014 10:55 PM add JPEG
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7/7/2014 10:01 AM	Rate (0)
mrfusion Member Joined: 6/26/2014 Last visit: 1/13/2020 Posts: 13 Rating: (1)	Hi, Thanks, that clears it up, if the display doesn't show scientific notation in the same way as in TIA when you watch the data then at least I know I wasn't doing anything silly. It is important for me to dispay the number exactly no matter the value. It is a KTP600 Panel. I actually get the value via RS232 in ASCII format so I have got around the problem by writing the number fromthe individual captured Chars into a String and sending that to the display and setting the "Display Format" to String and "Format Pattern" to "????????". I can just use the REAL for comparator operations for logic. But it would have needed less code if I could have just send the REAL to the display.
	Last edited by: furutsun at: 7/7/2014 11:02 AM
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7/7/2014 10:16 AM	Rate (0)
William_B Posts: 5225 Rating: (1198)	c´est la vie Thanks for the feedback.. _{small request: would you mind very much to share the coding to show your value on the panel?} Greetings. w
William_B Posts: 5225 Rating: (1198)
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7/7/2014 11:35 AM	Rate (0)
mrfusion Member Joined: 6/26/2014 Last visit: 1/13/2020 Posts: 13 Rating: (1)	You mean the ASCII Chars > String > HMI code? Or the original code that I had the problem with?

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7/7/2014 1:11 PM	Rate (0)
William_B Posts: 5225 Rating: (1198)	furutsun You mean the ASCII Chars > String > HMI code? Or the original code that I had the problem with? Hi there. Actually it is not really the coding. I am stuck with what the ASCII communications is giving you. .. as to extend my own knowledge, therefor my question. What is the format you receive from the communications? 1.234 E -5 or 0.00001234 or ??? Thanks. w
William_B Posts: 5225 Rating: (1198)
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7/7/2014 2:27 PM	Rate (0)
mrfusion Member Joined: 6/26/2014 Last visit: 1/13/2020 Posts: 13 Rating: (1)	The ASCII I read back comes in the formof "1,1.1e-1" from a TPG300 pressure controller Where the 1st number is a gauge status byte, and the number after the comma is a pressure value. I write the data into a DB into an Array of Char, so one char per byte. Then I write the Chars into a String so that the String to Real function in TIA can accept. This is +n.nnnnnnn-enn. So I pack it out with zeros to "+1.1000000e-01" and the function then returns the Real number in the format "1.1e-001" and this is what I was having trouble displaying on the HMI as a decimal with the formatting "9.9e".
	Last edited by: furutsun at: 7/7/2014 5:08 PM Last edited by: furutsun at: 7/7/2014 5:08 PM
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This contribution was helpful to 1 thankful Users William_B

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