9/26/2011 4:03 PM  
Posts: 22 Rating: (1) 
Hello! I'm somewhat new to PLC programming (took one general PLC ladder logic course in college, but never programmed before professionally, only academically). I'm trying to interpret some code but I'm unsure about something. Please view the following image: see attachment I've seen "E" (capital) being used to represent a *10^(n) operation. However, in all of my calculus and other math courses, "e" (lowercase) was always used as a mathematical constant. For example, 1*e^(1)=2.71828. Conversely, 1*E1=1*10^(1)=10. I'm assuming in the image I provide above, the "e" in "5.000000e002" is to be interpreted as a "*10^(n)" or "E" operation. Therefore, this function block is telling me to compute MD440.05. Is this assumption correct, or is it actually the mathematic constant described above? Thank you! 
Last edited by: O_Moderator at: 9/27/2011 8:15 AMpicture transferred to attachment Last edited by: AutoNub at: 9/26/2011 4:06 PMI''''''''m working with a Siemens® SIMATIC® STEP® 7. 

9/26/2011 4:16 PM  
Posts: 270 Rating: (52) 
Hello AutoNub, I don't see the picture above, however I am pretty sure that the right interpretation is 5.000000e002 means 0.05 as you say. That is the way numbers are interpreted in real/float by PLCs, there is perhaps somewhere some function to give one an Euler's number, but surely not in such notation. 
9/26/2011 4:16 PM  
Joined: 4/22/2010 Last visit: 12/15/2022 Posts: 5697 Rating: (708) 
Hello, Your assumption is correct, that's just the way step 7 notates a real(float. You can enter 0.05 and see when entered the step 7 software changes it into the figure you just shown in your picture. Regards, Marcjan 
Last edited by: Marcjan at: 9/26/2011 4:18 PMattached the picture for who cannot see it. Problem solved? 

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9/26/2011 5:38 PM  
Posts: 22 Rating: (1) 
Thanks so much for the helpful replies. I hope you don't mind, but I have a new question. I'm trying to figure out exactly what "L#" does and/or how it works. I understand the number following it makes it possible for the user to alter the overall value, but how do I calculate exactly what this value would be? For example, how would I calculate the value for L#100? What about L#73? Please let me know if you require more details. At this point, I'm assuming L# is a commonly used command or variable function (or combination thereof). I wasn't able to find information about it in the following document (which I've been using as a PLC function glossary), though: PLC Glossary 
Last edited by: AutoNub at: 9/26/2011 5:40 PMRemoved image because it was too large. Please see the attachment instead. 

9/26/2011 6:00 PM  
Joined: 4/22/2010 Last visit: 12/15/2022 Posts: 5697 Rating: (708) 
Hello, back again #L is the notation off a double integer, just not more than that. Have look at the helpfile, search for Data type to read more about it. Regards, Marcjan 
Problem solved? 

9/26/2011 6:07 PM  
Posts: 270 Rating: (52) 
Hello again, AutoNub, 
9/26/2011 6:37 PM  
Posts: 22 Rating: (1) 
Wow! This community is fantastic! Thanks so much for the very helpful replies. Kudos to you all! 
This contribution was helpful to2 thankful Users 
9/26/2011 10:38 PM  
Posts: 22 Rating: (1) 
I'll bet you thought I was done! Hehe, I did too... Anyway, another rookie question: new question is splitted to Is it acceptable to have an output before a function block, or do all outputs need to be at the end of each rung/network?. 
Last edited by: O_Moderator at: 9/27/2011 12:15 PMLast edited by: O_Moderator at: 9/27/2011 12:15 PMLast edited by: O_Moderator at: 9/27/2011 8:16 AM 

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