EATC-120 toolchanger driver

The EATC-120 module is almost finished !



This is a driver for the EmcoTurn 120/220 original 8 positions ATC.
This design is derived from the excellent Toolerator 3000 USB controlled driver.
EATC-120 is adding MODBUS capabilities for easy integration with an industrial environment.
Single 24V power supply with embedded 5V DC/DC converter.
The “brain” of the module is an Arduino Micro.
The motor is driven by an LMD18245T providing current control.
The lock status is automatically detected by measuring the peak current when the motor stalls.
Everything is reported in MODBUS registers.
Integration with Machinekit/LinuxCNC is easy thanks to “mb2hal” HAL component.

I have found a nice empty DIN rail enclosure and designed a special PCB to fit with it.



I need to finalize integration and test with my Emco lathe before publishing.

Stay tuned !

Control panel bracket

Just built a strong bracket for the control panel.
The door can slide freely under the panel.
Nest step is electrical cabling of the link between the control panel and the motor controllers.Control panel installed 01 Control panel installed 02 Control panel installed 03


Motor drivers

VFD and stepper drivers installed in the electrical box.
Vexta driver autotest feature shows that motors are in good condition and 5 phases cabling is ok.
Need to integrate the control panel for further validation.

Adding velocity estimation in hal_pru_generic encoder

I needed this feature for my lathe control panel project. The goal is to drive the jog steps size by the rotation speed of the jog wheels.

The algorithm has been validated from 5 Hz to 100 kHz.
Maximum measurement error is 1%. See curves below.

The patch is available here:


HAL configuration

loadusr -w ../

loadrt threads name1=servo-thread period1=1000000
loadrt hal_pru_generic prucode=$(HAL_RTMOD_DIR)/xenomai/pru_generic.bin pru=0 num_encoders=1 num_pwmgens=1 pru_period=2500 halname=hpg
addf hpg.update servo-thread
addf hpg.capture-position servo-thread

setp hpg.encoder.00.chan.00.A-pin 7 #925 ENCxI
setp hpg.encoder.00.chan.00.counter-mode 2 #Up Counter (counts rising edges on A, always counts up, B ignored)

setp 921 #PWM1
setp hpg.pwmgen.00.out.00.enable 1
setp hpg.pwmgen.00.pwm_period 1000000
setp hpg.pwmgen.00.out.00.value 0.5

loadusr -w sleep 1
loadusr -w python


import subprocess
import time
import os

def readpin(p):
 r = subprocess.check_output('halcmd -s show pin ' + p + '|head -1',shell=True) 
 lst = r.split()
 return lst[3]

def setpin(p, v):
 subprocess.check_output('halcmd -s setp %s %d' % (p, v), shell=True)

freq = 5.0
prev_freq = 0.0
maxerror = 0
f = open('result.csv', 'w')
line = 'in(Hz), out(Hz), err(%), latency(ms)'
print line
f.write(line + '\n')

while freq < 100e3:
 period = int(1e9/freq/2500) * 2500 # because pru_period=2500
 real_freq = 1e9/period
 if (real_freq <> prev_freq):
 prev_freq = real_freq
 setpin('hpg.pwmgen.00.pwm_period', period)
 measured_freq = float(readpin('hpg.encoder.00.chan.00.velocity'))
 latency = float(readpin('hpg.encoder.00.chan.00.latency')) * 1e-6
 error = abs(real_freq / measured_freq - 1.0)
 maxerror = max(maxerror, error)
 line = "%8.1f, %8.1f, %4.2f, %3.0f" % (real_freq, measured_freq, error*100.0, latency)
 print line
 f.write(line + '\n')
 freq = 1.1*freq

print "Max error %.1f%s" % (maxerror*100.0, '%')