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About ndzied1

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  1. It's hard to glean mechanical skills from an online class. I think the best to hope for online would be to pick up on terminology and identification of parts/tools (i.e. difference between hex and torx bits). If you have some machinery there give them tasks to work on that (of course teach safety first) Tasks that I think will be helpful for and electrical person learning mechanical skills. Depending on the student's level, they will need more or less guidance. Adjust a limit switch on a machine. Regardless of the type of switch, they are going to have to do some wrench/screwdriver turning and movement.  They will have to learn about alignment. Depending on the motion sensed, they will learn the trouble of adjusting the switch to actuate too soon. Or if they set the switch on the harry edge the problem of intermittent switching. Adjusting light curtains is also a good task. Have them do some wiring in a panel. Besides the screwdriver skill, they learn that it is not so easy to land the wires the right place. If you use ferrules, make sure they do the crimping of those too. Have them change out a pushbutton on a panel. Then have them verify that it works correctly. If you have any small motors in service you could have them take one off and put it back on. Show them the couplings and how they work. (good chance to go over lock out / tag out here as well). If you have any bigger contactors, have them take one apart and demonstrate how to change out the contacts.    It is good if you can pawn them off on other people in the company to help them with these tasks (talk with the other party first so they know what you're doing). Give them names of people but not their extensions or where they work. In my experience, the new one's want to do everything with texts or emails and not face to face. This gets them used to talking to people they don't know and talking face to face with people. Do give clear expectations. Be up front about making them find people on their own and talk to people face to face or on the voice phone.  Put them in situations where they have to call the tech support lines of manufacturers. Even if you can give them the answer right away, it will make them more self sufficient in the long run. 
  2. On the simple systems, I just program Manual to be NOT Auto.  Then all the logic to enter/leave auto is in the auto rung. It has some seal in branch and the manual PB breaks the seal. This avoids any possible races.   I have had customers that want 3 modes, MANUAL, OFF, AUTO.  For multiple modes I have found a series of latches seems to work best. Each button latches in it's mode and unlatches all the others.
  3. Standard Pumping Station Logic

    The logic may be flawed. I had a system that I programmed like this a while back (without the pressure maintenance requirement). With the logic of always starting the pump with the least run time and stopping the pump with the most run time you end up with all pumps with around the same runtime. This sounds good until you realize that, if all the pumps are identical, then they will all fail around the same time. You may want a startup phase that has a priority system to have some pumps run more than others. You should still throw all the pumps into the mix to keep them from extended off time. Eventually then, you could equalize the priorities of the pumps so that they get about the same amount of run time each week (or whatever time frame makes sense). Then they will all have different accumulated run times that keep increasing. The longest running pumps should fail first but the others will still have some life in them so you won't have to replace them all around the same time. It's a more complicated system but makes more sense in the long run.
  4. Assuming InVar is your word, you should be able to use dot notation to get to any individual bit in the word. The 2nd bit is at InVar.2 10th bit is at  InVar.10 and so on....
  5. best way to filter an analog reading

    I'm not sure what instructions are available in that PLC but if you have a modular division function (sometimes called MOD) then you can take the (value - (value MOD 5)) and you will get increments of 5. The modular division gives a remainder of the division so when you subtract the remainder, you essentiall round down to the next multiple.
  6. I think you'll want to check out this post. http://forums.mrplc.com/index.php?showtopic=12217&p=100125 There is a free version of RSLogix useable with the small controllers.
  7. You are correct. First I found an online calculator that procured a table of tank volume for every inch of liquid height. Not sure if this was the site I used but something like this: http://www.odayequipment.com/Support/TankChart/tankchartcalculator.shtml Then I read the table into Excel and created an X-Y chart of height vs. volume. I had to do a little number parsing to separate the height and volume numbers. Depending on your familiarity with Excel this can be a 1 minute simple task or a confusing mountain. Next I used a little known feature in an excel chart to get an approximate function representing the data. You right click on the chart line and select trend line. This plots the trend line which gives you a visual BUT, and here's the cool part, you can also ask Excel to display the equation for the trend line. This is where I got the polynomial coefficients in question. They are numbers that Excel spit out after it used its internal routine to create a best fit trend line.
  8. I attached a file showing how I would do it in the MLX1500. The calculation proceeds step by step using something called Horner's method. Volume = -0.0187*h3 + 4.0443*h2 + 163.51*h - 368.98 First you multiply the first coefficient (-0.0187) by the height and store it in F8:0 Then you add the next coefficient (4.0443) and store in F8:0 Then multiply this result by the height again and store in F8:0 Then add the next coefficient (163.51) and store in F8:0 Then multiply this result by the height again and store in F8:0 Lastly, add the last coefficient (- 368.98) and store in F8:0 At this point, F8:0 contains the result of the equation. For good measure, I usually copy the value from what I call the working register (F8:0) to another register (F8:2 in my example) so that if the volume is displayed somewhere the screen numbers don't jump around as the calculation is occurring. Hope this makes sense. If the calculation is confusing, I recommend writing it out by hand step by step so you can see how it works. TANKVOLUME.pdf
  9. Here's a pretty good approximation Volume = -0.0187*h3 + 4.0443*h2 + 163.51*h - 368.98 Volume is in gallons, height is in inches. It is not so good at the very bottom but at 14" liquid height it is only 5% off Starting at 25" liquid height, it is only 1% off and remains under 1% from here until the tank is full. I got this by putting your numbers into an online calculator that gave me the volume for every inch of height. Then I put these values into Excel and made a chart. Then I right clicked on the chart and asked for a trendline. I selected a polynomial order 3. You can probably increase the accuracy going to a higher order polynomial. If you just need a pretty good idea of volume for trending then this should be easy to program in the MLX1500. If you need commercial accuracy then this is not the way.
  10. You could use a Moeller EASY 821-DC-TC It has 10 bit analog inputs (0-10V) and 8 DC transistor outputs. And it mounts on a din rail http://www.moeller.net/en/products_solutio.../easy/index.jsp You can program it through the display but might be easier to use the software...
  11. Samples about ILC 150ETH from Phoenix Contact

    Did you order this as a starter kit? There should be a startup guide if you did. I think this link will get through: http://select.phoenixcontact.com/cgi-bin2/...amp;asid=898188 It should be a pdf with instructions and a sample project
  12. I have 3 TV's but if I watch more than 1 hr. a week it's rare. I understand the part about people trying to give you TV's. My father in law fixes old TV's and is always trying to give me one. I have actually never paid for a TV! Even the kids don't watch too much but like Russell, I do know more Hanna Montana songs than I care to. At least she has a pretty voice unlike the Jonas Brothers. Every year their school has what they call "TV Turn off week" which most kids cringe at but we've never had a problem with it.
  13. Small PLC with simple screen

    The Moeller Easy Relays have versions with screens. These are also marketed by Eaton (which owns Moeller) And by Allen Bradley as the Pico Line.
  14. sensing position in space

    It sounds like you found the solution with the BLG-1. Is this not an option? Can you touch the part with a probe arm connected to an encoder or something like that? Can you sweep a laser distance sensor slowly over the area on a slide and watch an analog input for a max value?
  15. need a new HMI for an old Klockner Moeller PLC

    Micro Innovation makes HMI's that will talk to the Moeller PLC. http://www.microinnovation.com I believe they are partially owned by Moeller. The problem is going to be finding the tags/addresses that the system is using. You cannot upload the program out of these PLC's. You should try to find out more about the existing HMI and see if you can get the configuration from that device. You might try to call Moeller or Micro Innovation to see if they can help you.