Push to ON PUSH to OFF PLC program using NO NC and Coil


This is  Interview question that every PLC programmer came across in his carrier.The Question is very tricky and shows the fundamentals (basic Ladder Laws) and depth of candidates knowledge.


Today we are going to discuss PLC program for Push to ON device  and Push to Off Device.But the trick is that we have to use  only Normally open(NO) ,Normally Close (NC) contacts ,and Coil as output only(No timer,Counter, OSR ). In short there will be a single Push Button Input (X0) , and one Output (Y0). When user press Push button for 1st time output will be ON ,when user Presses Push Button for 2nd time output will be OFF. This is also called as "Push to On Push to Off " logic.Analogy can be provided with "TV" on and off Push Button. 


  We Can Break Sequence Like This :
1) Push Button Pressed (X0) ==> Output (Y0)On
2)Push Button Released (X0)==> Output (Y0) Latched
3)Push Button Pressed (X0)==> Output (Y0 )Off
4)Push Button Released (X0)==> Output (Y0) Off

Remember you can write PLC program in number of ways 
  •  Using only NO,NC,Coil only
  • Using Counter
  • Using Pulse Instruction
  • Using OSR (Rising Edge ,Falling Edge) Instruction
 below program is using NO,NC,Coil

Note:Do not Replace M0 with Y0

Below Program is using Counter instruction

Below Program is using PLS instruction


More Question asked on this are related to Scan time and rung interchange etc.

Comments

Post a Comment

Popular posts from this blog

Build a Curve Tracer Circuit Diagram

Image
How to Build a Curve Tracer Circuit Diagram ? This is the simple Curve Tracer Circuit Diagram. This circuit Useful for checking diodes, transistors, triacs, SCRs, resistors, and LEDs, this curve tracer should prove useful in the experimenter`s lab.   Curve Tracer Circuit Diagram It displays the volt-ampere characteristic of a two-ter-minal device on an oscilloscope. This is a simple block diagram of the EZ-Curve. Current-limited AC signals are passed through both the device under test and a precision resistor to yield current and voltage readings.
Keep reading

Making an RIAA phono preamp

Image
Before we start today's blog post, I think I really need to clarify what we’re discussing. I’ve recently got back into vinyl in a big way. Part of the reason for this is the fantastic “Vinyl Decision” in Taipei, run by a couple of very fine gentlemen by the names of Mark and Terry ( https://www.facebook.com/VinylDecision / http://www.vinyldecision.com/ ). If you're in Taipei, and like music, pay them a visit. A recent purchase from there brought back memories of trying again, and again (and again) to play guitar like my guitar heroes as a teenager in the 1980s. In fact, vinyl is making quite a comeback worldwide. A lot of people are realizing that digital versions just lack some of the personality that vinyl can provide. Many of them are buying old record players/turntables and wiring them up to their modern amps. However, they are often disappointed to find that the output audio is very quiet and lacking bass. This is because records are/were recorded using a very specific f...
Keep reading

5 1 surround amplifier circuit schematic

Image
This 5.1 surround amplifier circuit schematic use the IC AN7168 as the main component from this circuit . Minimum voltage required 12V and maximum voltage 24V , I recomended it 12 V because the voltage support on are components. But if you want to better a loud sound you can raise it.  Maximum power output 40W with impedance 4 ohm . This 5.1 surround amplifier circuit schematic also support to make surround sound or 5.1 speaker. Use this amplifier on rear speaker , left right , and center but dont use to subwoofer speaker. See 5.1 surround amplifier circuit schematic below : Click to view large If you want to make a 5.1 surround sound you must make 5 the circuit of 5.1 surround amplifier circuit schematic , for left and right speaker , rear left and right speaker , and center speaker. Use the subwoofer speaker with support amlplifier subwoofer circuit .
Keep reading