YASKAWA SGD7S-xxxDA0 series Product Manual

Contents

6.14 Setting Unit Systems6.14.1 Setting the Position Reference Unit6-436 Basic Functions That Require Setting before Operation• Linear ServomotorsIn this example, the following machine configuration is used to move the load 10 mm. We’llassume that the resolution of the Serial Converter Unit is 256 and that the linear encoder pitchis 20 μm.Calculating the Settings for the Electronic Gear Ratio Rotary ServomotorsIf the gear ratio between the Servomotor shaft and the load is given as n/m, where n is thenumber of load rotations for m Servomotor shaft rotations, the settings for the electronic gearratio can be calculated as follows: Encoder ResolutionYou can check the encoder resolution in the Servomotor model number.For a Rotary Servomotor with an encoder resolution of 24 bits (16,777,216), Pn20E (Elec-tronic Gear Ratio (Numerator)) is automatically set to 16 and Pn210 (Electronic Gear Ratio(Denominator)) is automatically set to 1. Therefore, the encoder resolution will be equivalentto 20 bits (1,048,576). Consider this when you set the position reference unit in position userunit (2701h).When the Electronic Gear Is Not Used When the Electronic Gear Is UsedTo move a workpiece 10 mm:Calculate the number of revolutions.The motor will move 6 mm for each revolution,so 10/6 revolutions are required to move 10mm.Calculate the required number of referencepulses.One revolution is 1,048,576 pulses, therefore10/6 × 1,048,576 = 1,747,626.66 pulses.Input 1,747,627 pulses as the reference.If you use reference units tomove the workpiece when onereference unit is set to 1 μm,the travel distance is 1 μm perpulse.To move the workpiece 10 mm(10,000 μm), 10,000 ÷ 1 =10,000 pulses, so 10,000pulses would be input.Calculating the number of reference pulses for eachreference is troublesome.Calculating the number of ref-erence pulses for each refer-ence is not necessary.Linear encoderWhen the Electronic Gear Is Not Used When the Electronic Gear Is UsedTo move the load 10 mm:10 × 1000 ÷ 20 × 256 = 128,000pulses, so 128,000 pulses are inputas the reference.To use reference units to move the load 10 mm:If we set the reference unit to 1 μm, the traveldistance is 1 μm per pulse. To move the load 10mm (10,000 μm), 10,000/1 = 10,000 pulses, so10,000 pulses would be input as the reference.Calculating the number of referencepulses for each reference is trouble-some.Calculating the number of reference pulsesfor each reference is not necessary.= = ×BANumeratorDenominatormnElectronic gear ratio Encoder resolutionTravel distance per load shaft revolution (reference units)InformationSGM7J, SGM7A,or SGM7G -7 16,777,216F 16,777,216Code Specification24-bit multiturn absolute encoder24-bit incremental encoderEncoder Resolution