11/27/2016 7:03 PM | |
Posts: 29 Rating: (0) |
If I get temperature sensor with range of -50 to +50 celsius and have it send the temp via current-message ranging from 4 to 20mA How on earth I should configure the options of this analog trigger? Click for screencapture of analog threshold trigger options (same pic as an attachment also) If I type in range min. -50 and max 50 .. then try to type in offset -50 it will change the range settings to -24 and +80 .. Everything works with given parameters if I change the sensor type into 0-10V message type.. p.s. I dont yet have the sensor at my hands, im just designing this thing beforehand (this is my first attempt ever for doing some real world application with Logo :) |
Last edited by: tenuke at: 11/27/2016 7:04:50 PM |
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11/27/2016 7:23 PM | |
Joined: 12/18/2014 Last visit: 9/23/2024 Posts: 33817 Rating: (4201)
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In the attachment a video. There you can see the correct settings for a 4-20 mA sensor with a measuring range of -50 °C to 50 °C and a decimal place for the display. AttachmentTemperature -50 to 50 °C (4-20mA) with one decimal place.wmv (456 Downloads) |
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11/27/2016 8:23 PM | |
Joined: 12/27/2006 Last visit: 8/18/2024 Posts: 1197 Rating: (113) |
You only have to set: 1: Sensor type (4-20 mA) 2: Minimum value of the sensor by 4 mA (-500) 3: Maximun value of the sensor by 20 mA (+500) 4: Because the value of the temp is 10x to High you must set the nuber of digits.... to 1 LOGO Soft calqulate for you the gain and offset, dont change them manualy (exept when you know what you are doing) Tip: Use always an Analog Amplifier next to an analog input, is works better in your LOGO AttachmentCircuit Diagram1.zip (319 Downloads) |
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11/27/2016 10:07 PM | |
Joined: 12/27/2006 Last visit: 8/18/2024 Posts: 1197 Rating: (113) |
The LOGO cant make exact calqulations, it only works with hole numbers, no decimals byhind the comma. So if you multiply the value x 10 and place a comma 1 digit before the end the miscalqulations are more less. Try it at home. If you want to use a 4-20 mA sensor to the basic LOGO module you only can do it with setting a 0-10V sensor in the LOGO. You have to use a resistor of 500 Ohms (Read in the topic of ixo65 above this) And you have to make some calculations by youself on paper...... If use a -50 to +50 Degrees sensor then the hole span is (-50 to +50) = 100. Thats for 4-20 ma. So 1 mA is 100/16 = 6,25 degrees. 4 mA = 4x 6,25 = 25 degrees. Now you must let the LOGO think its a 0-20 mA (it is by the 500 Ohm resistor 0-10V) sensor. 4 mA = -50, so 0 mA = (-50 - 25)= -75 degrees. Setting in the LOGO: minimal -75 (or better 10x this value) 750 and maximal 50 (x10) = 500. Now its working. If there is no sensor LOGO let show you -75 degrees, and with the sensor and 4 mA there is -50 degrees. Exact what you wish. Dont forget the setting sensortype 0-10Volt. If you use a AM2 expansionmodule and your basic LOGO have analog inputs then the first analog input on the expansionunit is Ai3. You can set 4 Anolog inputs on your basic LOGO by software, then the first analog input on the expansionunit = Ai 5. If your basic LOGO has no analog inputs then the firstanalog input on the expansion uinit is Ai, AttachmentCircuit Diagram2.zip (246 Downloads) |
Last edited by: Toeternietoe at: 11/27/2016 10:09:11 PM |
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