12 HD65 & HD130 Stepper Drives User Guide

12 HD65 & HD130 STEPPER DRIVES USER GUIDE

Resolution	Stepping	DIP Switch
(with 200 step/rev	Mode	Settings
motor)		7	8
200 steps/revolution	Full step	ON	OFF
400 steps/revolution*	Half step	OFF	OFF
1,000 steps/revolution	1/5 step	OFF	ON
2,000 steps/revolution**	1/10 step	ON	ON

*Default resolution setting for HD65/130

**Default resolution setting for HD65/130M

Standby Current

Boost Current

The 1/5 and 1/10 step modes only apply if the optional microstep card is fitted (types HD65M and HD130M). In a standard drive (HD65 or HD130) the half-step mode is almost always preferable to full step, since the slight loss of torque is more than offset by smoother performance at low speeds.

The motor current is automatically reduced at standby; the reduction depends on the current setting, and is 50% with the drive set to its full current. At minimum current setting the standby reduction is to approximately 80% of regulated current.

A larger reduction may be obtained by changing R76 on the drive, which is normally set at 560 ohms. Reduce the value to reduce the standby current further. This resistor is located at the bottom of the PCB opposite the main power supply capacitor, and is accessible without dismantling the drive. Do not use a value higher than 560R without consulting Digiplan.

The standby current may be measured by a meter connected in series with one of the motor leads, or by using an oscilloscope (see "Test points" on page 14). Note that in modes other than full-step the current will vary with step position, so it is safest to make the measurement with the drive on zero phase. Remember to switch off before disconnecting a motor lead.

When boost is applied the motor current increases by approximately 30%. This is set by R77 on the drive and is normally 68K. The resistor is located next to R76 opposite the power supply capacitor, and its value may be increased in order to reduce the amount of boost. Do not use a value lower than 68K.

Anti-resonance Dropout Speed

The anti-resonance circuit is inhibited at speeds above 440 full steps/sec, and this is determined by R1 on the motherboard. The standard value is 47K, and halving the resistor value will double the dropout frequency.