Encoder comes with a specified PPR i.e pulse per Revolution and Maximum Frequency output of the pulses given by encoder. Generally, encoders are mounted on the shaft of the conveyor, so according to the resulting RPM we should select the encoder with a proper PPR and output frequency.
How to Find PPR and Maximum Frequency of Encoder
The encoder is interfaced with the PLC for counting the pulses given by encoder and taking the feedback. PLC inputs also have a frequency range for the pulses which it can accept. So calculating the frequency of pulses by the encoder is important in an application. Below is the formula to find the Max. The frequency of encoder in from the PPR and RPM.
Max. Frequency of encoder in Hz = (RPM / 60) * PPR
So if the encoder is mounted where the RPM = 2000 and PPR of the encoder is 360 the frequency of encoder will be 12KhZ. So we could find out that our PLC will be able to count pulses with this frequency or not.
Recommended Article: Using High Speed Counter in Omron PLC
Let us also see the difference between Single turn and Multi-Turn encoders.
In single turn Encoder, the output code is repeated after every single revolution of the encoder shaft i.e we can not actually determine how many turns have encoder made 1 or 1000.
In Multi-turn Absolute encoders, the output is unique for each revolution or for every shaft positions up to 4096 revolutions and we can get to know that the numbers of rotation of Encoder.
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