4-17
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Input/output (I/O) specifications
Pulley B
Encoder
Conveyor
Diameter
Pulley A
Example 2: Calculate the diameter ratio (RT) of the pulley when the rotary encoder is connected to the
conveyor through a pair of pulleys.
<Calculation conditions>
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Dot font
: 5
×
7 dots (horizontal direction 5, vertical direction 7)
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Inter-character space
: 1 dot (1 scan)
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Inter-character interval
: 1.8mm [horizontal direction 6 dots (6 scans)]
(inter-character dots 5 + inter-character space 1)
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Diameter of conveyor pulley : 60mm
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Resolution of rotary encoder : 1,000PPR
Amount of movement of conveyor per 1 revolution of rotary encoder
60mm
×
3.14=188.4mm/rev
Number of scans which must be executed while conveyor moves 1mm
6 scans/1.8mm=3.33 scans/mm
Necessary number of output pulses (resolution) from rotary encoder
188.4mm/rev
×
3.33 scans/mm=628PPR
Diameter ratio (RT) of pulley
RT=Diameter of pulley B/diameter of pulley A=1,000PPR/628PPR=Approx. 1.6/1
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Pulley
Diameter
Encoder
Conveyer
Example 3: Calculate the necessary rotary encoder resolution when a pulley is installed to the shaft of the
rotary encoder and this pulley is connected to the conveyor.
<Calculation conditions>
●
Dot font
: 5
×
7 dots (horizontal direction 5, vertical direction 7)
●
Inter-character space
: 1 dot (1 scan)
●
Inter-character interval
: 1.8mm [horizontal direction 6 dots (6 scans)]
(Inter-character dots 5 + inter-character space 1)
●
Diameter of rotary encoder pulley : 95.5mm
Amount of movement of conveyor per 1 revolution of rotary encoder
95.5mm
×
3.14=300mm/rev
Number of scans which must be executed while the conveyor is moving 1mm
6 scans/1.8mm=3.33 scans/mm
Necessary number of output pulses (resolution) from rotary encoder
300mm/rev
×
3.33 scans/mm=1,000PPR
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