Quad encoder

VSandhu · Jun 24, 2009

Hi, I am using a quadrature encoder using the A and B signals to calculate inches per pulse. Can someone help confirm or correct my calculation.

Roll diameter = 4 inches
Ecoder pulses/per revolution = 2

Circ = 4 * pi = 12.56

Circ/8(using the A & B signals and 2 pulses/per rev) = 1.57 inches per pulse

Thanks

PLCRookie · Jun 24, 2009

Ive never seen an encoder with 2 pulses per revolution. Post the brand and part number, and you will get more help.

VSandhu · Jun 24, 2009

It is a PHOTOCRAFT P/N HS20.625-P64Q. Basically you can configure it from 1 to 64 pulses per revolution.

I am using this for a belt conveyor where the encoder inputs land on a standard DC input card. That is the reason for the low pulse per revolution.

panic mode · Jun 24, 2009

for 4x evaluation, your calculation is correct.

bone · Jun 24, 2009

1.57 IPP....... How accurate do you need to be? Can you use a high-speed input card to increase your resolution?

Ken Roach · Jun 24, 2009

What kind of controller and input card are you using ?

What kind of belt speeds (and therefore shaft rotation speeds) do you need to measure ?

I realize you were just asking about the geometry of the system, but I recently taught an SLC-500 class where we carefully determined the response speed of discrete interrupts so it's on my mind.

VSandhu · Jun 27, 2009

I will be using a Control Logix L63 with a 1794-IB16/A DC input card.

The belt speed will be 300F/M.

Contr_Conn · Jun 27, 2009

I assume that 300F/M means 300 feet per minute.
This is 60 inches per second or based on your numbers 4.78 revolutions per second or 38.22 pulses per second or 26ms per pulse.
This means you need to deliver data and scan program at 13ms or faster.

So question is - how 1794IB16 connected to logix?
You probably should use some kind of counter module instead

BTW, 1794-IB16 has one channel counter that you can use if you are moving in one direction only

Quad encoder

VSandhu

Member

PLCRookie

Member

VSandhu

Member

panic mode

Member

bone

Member

Ken Roach

Lifetime Supporting Member + Moderator

VSandhu

Member

Contr_Conn

Member

Similar Topics