RE: Gecho 210 step multiplier, was Re: [CAD_CAM_EDM_DRO] Stepper Math

Of course ! Phase-lock loop and up-down counter.
How clever. Mariss, your drives are so cool. And your prices too !
I wonder how we could be without them. I've never bought a drive before
(because I"m just a beginner in this) but you can be sure they will be
Gecko's when the time comes.

Regards,
Guy


-----Original Message-----
From: mariss92705 [mailto:mariss92705@...]
Sent: Monday, February 25, 2002 3:14 PM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: Gecho 210 step multiplier, was Re: [CAD_CAM_EDM_DRO] Stepper
Math


Hi,

The pulse multiplier (G901) is a phase-locked loop circuit. Its
output goes to a G201 10 microstep drive. Its purpose is to appear
like a full-step or half-step drive to the user while it moves the
motor with microstep smoothness.

In full-step mode, all motor movements are in 10 microstep
increments. If you send it 200 step pulses, it will output 10 times
200 or 2,000 pulses to the 10 microstep drive it sits in. The motor
will take 1 revolution, just like a full-step drive, except the motor
will turn without vibration or resonance.

Here's how it works in full-step mode:

The steps you send it increment a 4-bit up/down counter. The
counter's outputs go to a 4-bit D to A converter. The D to A output
goes thru a PID compensation amplifier. Its output goes to a VCO
(voltage controlled oscillator). The oscillator output goes to the
G201 step input and to a divide by 10 counter. The counter's output
decrements the 4-bit up/down counter, which closes the loop.

In operation, the VCO frequency divided by 10 exactly tracks the
input step pulse rate. This means the VCO frequency is exactly 10
times higher than the input step frequency. It tracks the input
whether it is accelerating, decellerating or running at a constant
speed. The microstep smoothness is set by the PID loop co-efficients.
These values are based on optimum loop transient (lag-lead) response.

Mariss