Hitachi RX - Page 37

4-16 ●Input/output (I/O) specifications
PulleyB
Encoder
Conveyer
Diameter
PulleyA
Example 2: Calculate the diameter ratio (RT) of the pulley when the rotary encoder is connected to the
conveyer through a pair of pulleys.
<Calculation conditions>
●Dot font : 5x7 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 conveyer pulley : 60mm
●Resolution of rotary encoder : 1.000PPR
Amount of movement of conveyer per 1 revolution of rotary encoder
60mm x 3.14=188.4mm/rev
Number of scans which must be executed while conveyer moves 1mm
6 scans/1.8mm=3.33 scans/mm
Necessary number of output pulses (resolution) from rotary encoder
188.4mm/rev x 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 conveyer.
<Calculation conditions>
●Dot font : 5x7 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 conveyer per 1 revolution of rotary encoder
95.5mm x 3.14=300mm/rev
Number of scans which must be executed while the conveyer is moving 1mm
6 scans/1.8mm=3.33 scans/mm
Necessary number of output pulses (resolution) from rotary encoder
300mm/rev x 3.33 scans/mm=1,000PPR
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