up down counter

[radium1212]

up down counter

Could anybody let me know the principle how up down counting is done using 2 micro switches or proximity switches. I can figure out the electronics to start counting up or down.
If i have 2 sensors, (proximity or on/off switches) , what is the principle and wiring of the switches , used to make it count the number of turns of the wheel, increasing clockwise and decreasing anti cw . The wheel is hand turned and will have a cam or plate to activate the switch or proximity switch serially or one after the other.
thanks

 

[Hero999]

Normally an incremental rotary encoder is used.
Rotary encoder - Wikipedia, the free encyclopedia

It has a quadrature output.

How are you planning to do this?

You could use a micro-controller or do it the old way and just a shift register and logic gates to determine the direction?

 

[radium1212]

Thanks Hero999 for your reply
A gate valve with a large wheel needs to be open and closed 75 turns. Hence I intend using 2 proximity switches and discreet electronics. However, I have seen this been done for paying out wire rope over a pulley and the counter counts the pulses and calculates the length based on the diameter of the pulley. It sense which switch was actuated first followed by the second and hence determines the direction. I need to figure out how this is direction is used to count up and down.
tks again
radium1212

up down counter

Could anybody let me know the principle how up down counting is done using 2 micro switches or proximity switches. I can figure out the electronics to start counting up or down.
If i have 2 sensors, (proximity or on/off switches) , what is the principle and wiring of the switches , used to make it count the number of turns of the wheel, increasing clockwise and decreasing anti cw . The wheel is hand turned and will have a cam or plate to activate the switch or proximity switch serially or one after the other.
thanks

 

[Reloadron]

Thanks Hero999 for your reply
A gate valve with a large wheel needs to be open and closed 75 turns. Hence I intend using 2 proximity switches and discreet electronics. However, I have seen this been done for paying out wire rope over a pulley and the counter counts the pulses and calculates the length based on the diameter of the pulley. It sense which switch was actuated first followed by the second and hence determines the direction. I need to figure out how this is direction is used to count up and down.
tks again
radium1212

If you want to do this using discreet components attached is a crude start using an old 74192 programmable up/down counter. I suggest you look at a data sheet for the chip. Additionally the cartoon shows a single chip but they can be cascaded giving you tens and units so you can count up to 75 and down from 75 (actually up to 99 and down to 00). Your sensor tells it to count up or down and another sensor provides one clock pulse per revolution of the gate valve. There are other chips that could be used but the cartoon should get you going with an idea or two.

Ron

 

[radium1212]

Hi Ron,
Thanks for your advice and circuit.
Could you advice me how I could wire the sensor to sense that the direction is for eg: turning cw and then suddenly ccw and provide a high or low accordingly??

 

[Reloadron]

Hi Ron,
Thanks for your advice and circuit.
Could you advice me how I could wire the sensor to sense that the direction is for eg: turning cw and then suddenly ccw and provide a high or low accordingly??

Keep in mind that if I were doing this for work I would do it using the earlier ways mentioned. I would use a rotary encoder for valve position. The output of which would feed a totalizer configuration. I would likely use a BEI encoder as we use them quite a bit where I work. I would not do this with discreet components using archaic chips.

However, after work today and into the weekend as time allows I'll try to give you some suggestions based on the drawing I posted. Motor driven valve? Sensors for full open and full closed? There are 75 turns either direction? What exactly should the circuit do?

Do you have any thoughts on the sensors you plan to use?

Ron

 

[radium1212]

Hi Ron,
Thanks for your input. Do appreciate it.
Its a big wheel , about 2 feet in diameter that has to be opened by hand and takes 75 turns from fully open to fully shut. Its not a motor driven valve, the wheel is like a car sterring wheel, heavy metal. I plan to use 2 proximity switches. These have been used on 2 occassions earlier for counting the length of wire payed out over a pulley, but I dont know how it was done. They use 2 proximity switches besides each other and based on which one gets activated first, it tells the direction. The pulley had a metal patch that passed the 2 proximity one after the other as it turned.
tks again and will look forward to your advice.
Roy