1/24/2009 11:50 AM | |
Posts: 40 Rating:
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Does anybody out there have some positive experience with one LOGO! software to manage 8 or 16 channel PT 100 Multiplexer connected to the SIEMENS LOGO!? AttachmentRTM-8.pdf (650 Downloads) |
1/24/2009 5:39 PM | |
Posts: 40 Rating:
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I've beencreating and testingthe Softcomfort file enclosed "8-16 PT100 Multiplexer" and it works with 8 PT100 inputs from one Multiplexer device connected to LOGO! by four outputs: Q1, Q2, Q3, Q4. With this file should be possible to expand upto 16 PT100 inputs for one Multiplexer with 16 PT100 inputs. I'm just wondering if those output relay won't die soon for excessive work (sampling rate of 2 seconds...) Have you any opinion ? Thanks. Paolo Attachment8-16 PT100 Multiplexer.zip (702 Downloads) |
1/25/2009 3:49 PM | |
Joined: 1/5/2007 Last visit: 4/7/2023 Posts: 1690 Rating:
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Hi Solar Element, in the middle of 2007 a german member has the same idea as you and i have programed a full application for him to control and use an external 16xPT1000-multiplexer with 3 LOGO! basic modules... In the attachment here i have give you some program parts as info how i solve this area: a) I think, because the load of the four digital outputs ist verry low (for adress codes), it is possible for a litte time and/or for testing to use relais outputs. But for general use to control an external multiplexer it was the best to use one add-on module DM8 24 with transistor outputs (with no limit of the frequency and ther life time)! b) Remenber, the controll and using of 16 sensors needs a lot of blocks for organisation... c) My first version to generate the adress codes was the same as yours, named BCD-code...At file "Test_LOGO_2b (two_groups) V1.lsc" you can find this (at top, left side). The solution shows a modification of the scaning too, because it gives tempeatures witch needs a high actualisation rate and other needs only a low rate. The modification allowed to define 2 groups of sensors and to set the number of scans for any group....That can help to reduce the scan time between any code adresses... d) My second version of coding the adress bits you can find in the file "LOGO_Teil_2b_von_3 (external_multiplexer_A).lsc" (at top, left side). Internal i have made no modifications, but i give now to the four outputs a new code named gray-code (If you program new, it is better to use only gray-code, because this saves blocks.) By scaning all code adresses by this code, it must only one of the four outputs change his state - and this saves the output relais!). For more info about gray-code look at the attached files or the internet. e) The file "LOGO_Teil_3c_von_3 (external_multiplexer_B).lsc" you can look how it is possiple to analyze incomming gray-code to decode into BCD and use this to get the analoge values of the sensors....That is a way to split a program to two or more LOGO!-basic muduls to use more blocks in sum.... f) All the 3 files contains a simple condition for the input signals too: g) Altenative to f3) now i can give you a better methode, special for use with analog inputs from AM2 (PT100) module with 50 ms actualisation time. Look at file "DEMO_periodische_Mittelwertbildung_V2.lsc". It contains a citcuit to calculate the mean value of a analog input for n individual values!. Set the time between two individual values in the puls generator, set n in the parameters ON = OFF = n of the counter AND build with the needed equation to scale the input(s) a summary equation into one amplifiver - that means combination of division by n and scaling temperature: I hope this statements will help you! I have not the time to translate all - if you have any queastion more about the german comments into the files, then ask me here! Best regards AttachmentFORUM_Mexx_external_mutiplexer.zip (625 Downloads) |
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1/27/2009 9:48 PM | |
Joined: 1/5/2007 Last visit: 4/7/2023 Posts: 1690 Rating:
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Hi Solar Element, this modul is only for PT1000 - the new distributor is: http://www.rinck-electronic.de I think you can only search over thge internet....perhaps the following links can help also: http://www.techno-job.nl/pt100_multiplexer1.htm http://www.ziehl.de/ziehl/englisch/indexe.html(Measuring Point Change-over Switch MUM for 8 or 16 Measuring Points) Best regards Betel |
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