TozoM8 Posted May 31, 2013 Report Share Posted May 31, 2013 I am working on a project that has a scale to load the machine. If the feeder is less than 350 lbs the operator is able to turn on the blower to fill more material into the feeder. When the weight reaches 350lbs the blower stops and the feeder automatically loads the material into the machine. When the scale is empty (0 lbs) it stops the loading and goes to the next step. I am having trouble to set the TARA and the 100 lbs calibrating point. I am trying to "store" linear X to Y1 as a 0 (tara) point and use the math functions to set/teach 100 lbs when I put my 100 lbs weights on the scale. Neither works so far. I would greatly appreciate any help with this. Thanks! scale sample.vlp Quote Link to comment Share on other sites More sharing options...
Gabriel Franco Posted May 31, 2013 Report Share Posted May 31, 2013 Are you using IO-LCx module? If so, you don´t need LINEAR function, rather than, use calibrate, acquire tare and acquire zero FBs. In that way, operand associated with your hardware gives weigh value in the units you calibrated. Quote Link to comment Share on other sites More sharing options...
TozoM8 Posted June 1, 2013 Author Report Share Posted June 1, 2013 No. I have 3 load cells connected to an amplifier sending out 0-10V. I am using the V200-18-E3XB. I have the display setup and it shows my weight. I am using the enable charge, full and empty settings and everything works fine. The problem I have is that I want to set 1V (410 counts on X2) as my 0 lb on the display so if the scale goes out of calibration (below 410 counts) I would see it as - *** lbs on the display instead of just showing 0lb. I have this working on a different machine, but that uses an omron plc and I have no access to the program to figure out how they did it. If I could set Y1 to 0 then it would be my 0lb on the display (tara). Quote Link to comment Share on other sites More sharing options...
TozoM8 Posted June 10, 2013 Author Report Share Posted June 10, 2013 I don't have a problem showing the weight. The display is configured 4 digits, 0-1000lbs. What I can't figure out how to set a new Tara. Example if I replace a part on the machine that will make it 5lbs lighter, the scale will read 0000 instead of -0005lbs and I have no way to make that a new 0000 point other than re-calibrating my amplifier. Quote Link to comment Share on other sites More sharing options...
MVP 2023 Joe Tauser Posted June 10, 2013 MVP 2023 Report Share Posted June 10, 2013 Tare is an offset, not a re-calibration point. The output characteristics of your load cells doesn't change just because you put something on it. You need to subtract the tare value after you've calibrated the scale with nothing on it and with a test weight. Look at this program. I have moved the working register to MI 20 - let me know if it does what you want. Joe T. scale sample JT.vlp Quote Link to comment Share on other sites More sharing options...
TozoM8 Posted June 11, 2013 Author Report Share Posted June 11, 2013 Thanks! I will try it tomorrow. Quote Link to comment Share on other sites More sharing options...
TozoM8 Posted June 11, 2013 Author Report Share Posted June 11, 2013 It worked great, thank you! The only problem I have when I restart the PLC I have to re-teach the scale for the 100lbs. Quote Link to comment Share on other sites More sharing options...
TozoM8 Posted June 11, 2013 Author Report Share Posted June 11, 2013 Figured it out. I had MI16 with power up condition checked with 100. Unchecked it and it works fine. Thanks again! Quote Link to comment Share on other sites More sharing options...
egato Posted December 16, 2014 Report Share Posted December 16, 2014 Hello, We have made an application with PLC V120-22-R1 and IO-LC3 for weighting with a crane. As an option we want to implement a diagnostic display for microvolts measurement of loadcells using function "Change representation mode". But only Gross Weight or Net Weight is displayed.The LC Command Status Messages MI returns always "3" when this function is activated. I would greatly appreciate any help with this Quote Link to comment Share on other sites More sharing options...
s.pratt Posted December 17, 2014 Report Share Posted December 17, 2014 Hello egato, The LC command status of '3' states that the I/O expansion module (the LC module you are trying to change the representation mode on) is busy at that time. This may be due to trying to change the representation mode and conducting another LC command too soon. Please note, it takes 330msec to change between representation modes. Also, please note, changing the representation mode of one value to mV/V will force the representation mode of both values to mV/V (net and gross). Quote Link to comment Share on other sites More sharing options...
egato Posted December 18, 2014 Report Share Posted December 18, 2014 Hello S.Pratt I have reviewed the program and there is only a call to the function "change representation mode" I have modified also to ensure that this only LC command is called, but the result is the same as before:LC Command Status Messages MI returns "3" when the function is just called and don´t change to "1" Quote Link to comment Share on other sites More sharing options...
s.pratt Posted December 18, 2014 Report Share Posted December 18, 2014 Hello egato, Are you sure you are triggering this function command off of a positive transition contact? We have seen this status message related to the function being called in too many scans. Quote Link to comment Share on other sites More sharing options...
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