panic mode

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About panic mode

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    Mitsubishi Moderator
  • Birthday 12/15/69

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  • Location Mississauga, ON
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  1. i would expect that candidates have strong theoretical understanding and can explain what goes on and can prove to me they are quick learners. experience is nice but i prefer good attitude and no experience - specially over bad experience. not experienced person can quickly gain experience with a bit of coaching in the workplace (and this gives me a chance to make sure he/she does it the proper way). wrong kind of experience is still experience but... it is bad and dangerous... correcting this requires a lot of un-learning... and i don't have time for that.  actually using VFD is not a perfect substitute for real 3-phases - VFD output is a chopped DC, not a sinewave. This also means you need to at least use TrueRMS multi-meter and know what to expect. anything less is waste of time. if you can get your hands on it, try ganging two motors, one as motor and other as a 3-phase generator. this can also be very small or low power for those willing to experiment.   things that bug me is candidates that waste my time. that includes people that: - don't understand social effects of (not using) shower, laundry and personal hygiene (you would not believe how many people show up with BO, greasy hair etc.). this is what makes meetings VERY short... - cannot read and write. knowing alphabet and ability to communicate verbally is only the most rudimentary skill set. i still need to see handwriting, basic algebra, basic computer skills, critical thinking etc. (yes, give them small word problem and see how they do, my 15 year old son is doing that in school and he is good at it, adult should be able to at least match it). if i cannot EASILY read their notes, i cannot have them complete service reports, note down reasons why equipment is locked down etc. if someone failed to learn how to read and write in 12+ years of schooling, they came to a wrong place to ask for another chance, i am not that good of a mentor. - send resumes without proofreading them. when they type it, word processor tells if there is a spelling mistake. demonstrate that you know how to use it before you email that resume. and i specially love it when they state great communication skills but use inappropriate language, terminology or mess up resume. - don't understand electric power but want job that requires knowing it. those who cannot explain difference between P=V*I, P=V*I*cos(phi) and P=V*I*cos(phi)*1.73 need not apply... - don't understand Ohms or Kirchhoff's Laws or how multi-meter behaves in a circuit. easily tested on paper by drawing mixed circuit of various meters and a power source. i may also throw in resistor just to give them some hope.  - don't understand operation of transformer and voltage divider   That would be just a set of "no nonsense" checks to weed out 95% of "candidates". real interview starts after this...    
  2. ASCII !@#$!@#(*&^

    "27" is two bytes or characters or SINT. "2" = 0x32 = 3x16+2 = 50 decimal "7" = 0x37 = 3x16+7 = 55 decimal  
  3. I am sorry and I apologize... Another moderator informed me that that was link to updates only and that those are free... Your status is restored and warning is removed.




  4. incremental encoder missing counts

    as Joe stated, can you verify actual length of cut pieces and confirm if there is an error or not? if there is an error, then troubleshooting is needed (shielding, configuration,..) 
  5. CP1E Analog input connection and programming

    do you know what a potentiometer is? you MUST connect all three terminals. brown wire is positive blue wire is negative yellow wire is analog output...   
  6. CP1E Analog input connection and programming

    that is not LVDT, it is a linear potentiometer...  read datasheet, it tells that max current through it is 10mA which will be no problem if you power it by 10VDC source. then you can use its output directly although that is not recommended. max wiper current is recommended to be less than 0.1uA. Ohms law states R=V/I = 10V/0.1uA = 100MOhm. No analog input on PLC has such high impedance. Usually they have 0.1-1MOhm. To properly use such device one would need buffer of some sort (voltage follower) with high input impedance.    
  7. HC-SRO4 an arduino Sensor

    No PLC can use this kind of sensor directly.   This type of sensor requires controller to initiate measurement and capture echo with very precise timing - something PLCs simply cant do (need I/O that respond within micro seconds). You can use microcontroller and convert signals to something PLC can read or - choose an industrial sensor with output that is compatible with PLCs (this is simple to interface  but it will cost hundreds of $). if you are on a budget, just throw in Arduino as a converter... you can transmit signal to PLC in different forms (analog, serial, parallel).   Btw. ultrasound sensors have some peculiarities, cannot use more than one at a same time (syncing required), sensing field is conical (pretty wide) so target need to be reasonably large and reflect sound, sloped surfaces work as mirrors and deflect beam in another direction, one does not see what exactly sensor is looking at etc. Where possible (99.9% of times) lasers work better. Some low cost industrial distance sensor is for example O1D100 (should be 2-3 times cheaper than ultrasonic).  
  8. Hi Friend,

    Do you haveany idea of how to create queue in mitsubishi PLC?




    yep... we all have been there... anyway, this is not plug and play... what commissioning steps have been completed? message suggests to check mains power. what messages servo drive reports? is everything connected correctly (motor, encoder, over-travel switches,...) and configured (motor type, gear ratio etc.)?  

    in just 15min you created four identical topics. stop spamming or you will be banned... give chance to someone to respond.
  11. to do positioning you need a servo. in recent years some VFD drives (but not all) also support this functionality. to do any kind of precision you need tight loop. normally that loop is part of the drive or motion controller. You can of course use PLC  code for this but the fact remains that this is not a fast loop resulting in loss of performance (either speed or accuracy or both). using only contactors to control motor in an attempt to control position is exercise in futility. another issue is braking (slowing down). if you need an example, use any cheap motor (ceiling fan, drill gun etc) and try to operate it manually using switch and - stop at specific position. it just wont work... if you have VFD, you can control velocity (and deceleration!!!). this allows you to slow down axis before reaching stop position. with clever code and calculating deceleration ramps etc this can get you potentially close to what you expect. theoretically the only compromise would be speed. the other issue is that induction motors are designed to operate at specific speed (within some tolerances).  
  12. Bit Shift GX Works2 shifting 2 bits simultaneously

    Can you please elaborate on this.. 
  13. Trouble Wiring a Simple LED with a Micro820 Controller

    LEDs are polarized devices like all diodes. When forward biased voltage drop is usually 2-3V and current is usually 5-20mA. To operate on higher DC voltage al you need is series resistor but 10K will be too high value (LED will likely show some output but very dim).  If we assume 15mA (0.015A) and 3V for LED, then resistor will be 21V/0.015A = 1400 Ohm. Nearest common value is 1.5k and it should be rated for 0.5W    But keep in mind that reverse biased LED will not survive if it is connected to voltage that exceeds some 6-7V.  common solution is to either make sure this will never happen or protect LED somehow. simplest solution is to wire another diode anti-parallel to LED. another option is to use bridge so polarity will not matter.  
  14. Binary string to int conversion

    i agree, using string to represent numeric values is less than ideal. but if that's what you have, use a loop and go through each string character, something like this (sample pseudo code): INT N, I N:=0 FOR I:=1 to stringData.LEN   N:=N+N   if stringData[I]=='1' then       N:=N+1   endif NEXT  
  15. Binary string to int conversion

    and post your code