Detail 4131 103 ep potentiometer IC use as 10k Potentiometer resistanceVDD = Positive power supply 1.8 to 5.5 VoltagePBO = Resistance face B side (Link in VFD (Variable Frequency Drive) V1I point)PAO = Resistance face Aside or (Link in VFD (Variable Frequency Drive) V1I point)PWO = Resistance wiper (Link in VFD (Variable Frequency Drive) Gnd point)VSS = Negative power supply 1.8 to 5.5 VoltageCS = Chip Select (SPI port chip select pin used to execute a new command after it has been loaded into the shift register) this point connected in CNC Controller out point without relaySCK = SCK is the Shared/Serial Clock. It is the SPI clock line. this point connected in CNC Controller out point without relayMach3 interface board connection output point Below a detailStep 1: Connect mach3 board PWM output in 4131 ic SCK pin no 3Step 2: Next connection 4131 ic pin no 1 connect to Mach3 interface board GND pointStep 3: let's go and connect ic VSS pin no 4 negative 5v power supply from Mach3 Interface boardAll the above point connection between the Mach3 interface to 4131 resistance ICStep 4: In 4131 ic pin no 8 Postive 5v power supply from Mach3 interface boardOur VFD Drive knows much output and input. So we are sure that use the only 10 k Resistance (Potentiometer) point. A, W, B point is an out Potentiometer resistance below ming of the pointA = This fix pin in VFD attach this one end of the resistive point (A point resistive)W=This fix pint in VFD attach this second end of the wiper point (W point Call wiper)B= This fix pin in VFD attach this third end of the resistive point (B point resistive)Step 5: Let's goPBO pin no 7 in our potentiometer ic connection VFD output port B point of potentiometerStep 6: PWO pin No 6 connection in VFD point W (Wiper) as the primary control point in speed controlling Step 7: Now final point connection PAO pin no 5 in our potentiometer ic connection VFD output port A point of potentiometerThis is the use of automatic speed control by the CNC controller.This method also uses VFD speed control.