1/21/2018 3:35 PM | |
Joined: 11/15/2017 Last visit: 9/2/2022 Posts: 87 Rating: (0) |
Hello, I am looking to control the temperature in a hot water tank(50,000 litres capacity),can this be done using a 4-20mA output signal to the 3 way valve. I have a logo 8 (0BA8) am2 rtd and am2 AQ modules, I have used some of the examples from this site to run simulations to the required set points eg 55 degrees(for legionella purposes). But I am not having much success bringing the am2 AQ into play within my test programs.I do not get the desired output to drive the valve which is rated @4-20mA. Do I require any other hardware to carry this out or am I missing something within the program,I am able to use a digital output within the simulation but as soon as I try to use an analog output within the program I get the error incompatible connectors.I have attached my first attempt it includes an over temp alarm and wire break it is work in progress but some guidance would be gratefully received please forgive my lack of experience in using logo many thanks Attachmentproject_HWTEST.zip (183 Downloads) |
1/21/2018 5:03 PM | |
Joined: 12/18/2014 Last visit: 9/25/2024 Posts: 33834 Rating: (4205)
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How works the valve? 4 mA = 100% heating? 12 mA = nothing to do? 20 mA = 100% cooling? |
1/21/2018 8:24 PM | |
Joined: 11/15/2017 Last visit: 9/2/2022 Posts: 87 Rating: (0) |
I'll start from fresh to see if this scenario is feasible 1.water in tank to be heated using thermal oil which will be allowed into tank via http://www.samsoncontrols.com/product/v20013535-3-way-valve-heat-transfer-fluid 2. Valve to open when temperature is below 55 degrees 3. Valve to close when temperature is equal to or above 55 degrees 4.4 wire 2xpt100 input (RTD AM2) 5. 4-20mA output (AM2 AQ) signal to control I/P on 3 way valve. 6.Alarm count if temperature should ever reach 60 degrees |
1/22/2018 5:56 AM | |
Joined: 12/18/2014 Last visit: 9/25/2024 Posts: 33834 Rating: (4205)
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I have to confess, I got confused by your program. Now my program proposal to keep the temperature in the tank at a preselected value. Attachmentproject_HWTEST_V2.zip (199 Downloads) |