Sigma II User’s Manual Chapter 5: Parameter Settings and Functions5 - 285.2.5 Using the Electronic Gear FunctionThe electronic gear function enables the servomotor travel distance per inputreference pulse to be set to any value. It allows the pulses generated by the hostcontroller to be used for control without having to consider the equipment gear ratioor the number of encoder pulses. Setting the Electronic GearCalculate the electronic gear ratio (B/A) using the following procedure, and set thevalues in parameters Pn202 and 203.1. Check equipment specifications related to the electronic gear:• Deceleration ratio• Ball screw pitch• Pulley diameter2. Check the number of encoder pulses for the SGMH servomotor.Note: The number of bits representing the resolution of the applicable encoder is not the same as theServomotor Modeland EncoderSpecificationsEncoder Type Number of Encoder PulsesPer Revolution (PPR)AIncremental encoder13-bit 2048B 16-bit 16384C 17-bit 327681 Absolute encoder 16-bit 163842 17-bit 32768When the Electronic GearFunction is Not UsedWhen the Electronic GearFunction is UsedBall screw pitch: 0.24in. (6mm)WorkpieceNo. of encoder pulses: 2048 No. of encoder pulses: 2048WorkpieceBall screw pitch: 0.24in. (6mm)Reference unit: 1μmTo move a workpiece 0.39in. (10mm):1 revolution = 6mm. Therefore,10 ÷ 6 = 1.6667 revolutions.(2048 × 4) pulses = 1 revolution. So,(1.6667 × 2048 × 4) = 13653 pulses13563 pulses are input as the reference.The equation must be calculated at thehost controller.To move a workpiece 0.39in. (10mm):Equipment conditions and referenceunits must be defined for the electronicgear function beforehand.Reference unit is 1μm. Therefore,10mm1μm = 10000 pulsesBall screw pitchDeceleration ratioGear Ratio
