[?]: absolute encoder value is greater than the maximum

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seee
Posts: 10
Joined: Tue Mar 22, 2011 7:24 am

[?]: absolute encoder value is greater than the maximum

Post by seee » Mon Dec 12, 2011 8:19 am

hello.

i have an absolute encoder which is 12 bit and 4096 revolutions.
the maximum output value of the encoder is 2^12=4096*4096(revolution)=16777216
i read the encoder value in plc s7-300 in variable table with instruction
pid256 and it showed dw#16#51d72800 this value is greater than the maximum
output value of the encoder(16777216)! why?(if i turn encoder 4096 the maximum output value must be 16777216)!

how can i read encoder value and compare it with 4096 in order to know that
the encoder has been rotated 1,2,3 etc turns?

best regards.

NickLu2
Posts: 31
Joined: Wed Apr 21, 2010 4:25 pm

Re: encoder value

Post by NickLu2 » Wed Dec 14, 2011 8:48 pm

i have an absolute encoder which is 12 bit and 4096 revolutions.
the maximum output value of the encoder is 2^12=4096*4096(revolution)=16777216
i read the encoder value in plc s7-300 in variable table with instruction
pid256 and it showed dw#16#51d72800 this value is greater than the maximum
output value of the encoder(16777216)! why?(if i turn encoder 4096 the maximum output value must be 16777216)!
What kind of input card is used for encoder connection? Maybe it has some memory to count pulses from encoder and thus can be reseted to start counting from zero?
how can i read encoder value and compare it with 4096 in order to know that
the encoder has been rotated 1,2,3 etc turns?
Try to make one rotation of encoder and compare values before and after and their difference

seee
Posts: 10
Joined: Tue Mar 22, 2011 7:24 am

Re: [?]: absolute encoder value is greater than the maximum

Post by seee » Thu Dec 15, 2011 6:26 am

hello.

it is an absolute profibus encoder.i have connected it to dp port of cpu315-2dp.

best regards.

NickLu2
Posts: 31
Joined: Wed Apr 21, 2010 4:25 pm

Re: [?]: absolute encoder value is greater than the maximum

Post by NickLu2 » Thu Dec 15, 2011 8:40 am

Who is the manufacturer of encoder? Can you show the part of program which read and process related input?

Pong Qinaya
Posts: 2
Joined: Tue Apr 12, 2011 4:16 pm
Location: South East Asia

Re: [?]: absolute encoder value is greater than the maximum

Post by Pong Qinaya » Mon Feb 27, 2012 9:29 am

i think your Encoder use GRAY CODE

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