axis

Axis is Python module for controlling stepper motors with MLAB HBSTEP01B based on ST L6470 inteligent stepper motor driver.

Class axis is prepared for use with multiple ways of connecting to the control computer.

I2C (PyMLAB)

Connecting HBSTEP01B with control computer with I2C requires I2C-SPI translator supported with pymlab. For example I2CSPI01A or SC18IS602B equivalent.

AROM (ROS framework)

Using with AROM requires fully installed and configured AROM and running pymlab_bridge.

SPI

Examples

Example with I2C

cd ~/repos/axis/examples
python i2c_example.py

This example requires working PyMLAB.

import axis
from pymlab import config

cfg = config.Config(
        i2c = {
            "port": 1,
        },

        bus = [
            { 
            "name":"spi", 
            "type":"i2cspi"
            },
        ],
)

cfg.initialize()
spi = cfg.get_device("spi")
spi.SPI_config(spi.I2CSPI_MSB_FIRST| spi.I2CSPI_MODE_CLK_IDLE_HIGH_DATA_EDGE_TRAILING| spi.I2CSPI_CLK_461kHz)

motor = axis.axis(SPI = spi, SPI_CS = spi.I2CSPI_SS0)
motor.Reset(KVAL_RUN = 0x90, KVAL_ACC = 0xF0, KVAL_DEC = 0xF0, FS_SPD = 0xFFFFFF)

#motor.setConfig(EXT_CLK = 0b1, OSC_SEL = 0b110) # Ext clock source: 24 MHz(Crystal/resonator driver disabled)

motor.Float()
print motor.GetStatus()

i = 0
while True:
    print "loop"
    motor.MoveWait(5000)
    motor.MoveWait(-5000)

Example with AROM

Example with AROM (Autonomous robotic observatory manager) is attached to AROM repository.

To run an example is needed to have installed AROM, PyMLAB and this Axis class.

Before running example you must have configured and running pymlab_bridge AROM node. Configuration is described at MLAB wiki page

Pro tento příklad je potřeba mít vytvořený konfigurační sobor /home/odroid/robozor/station/pymlab_presets/telescope.json s následujícím obsahem:

{
        "name": "pymlab", 
        "children": [{
                "port": 1, 
                "name": "bus1",
                "children": [
                {
                        "type": "i2cspi", 
                        "name": "spi"
                }]
        }]
}

Nyní by mělo být možné spustit pymlab_bridge příkazem

rosrun arom pymlab_bridge. Po spuštění můžeme spustit samotný příklad rosrun arom demo_HBSTEP

Using

Reset

def Reset(self, init = True, ACC = 0x00a, DEC = 0x00a, stall_th = 2030, ocd_th = 3380, KVAL_HOLD = 0x29, KVAL_RUN = 0x29, KVAL_ACC = 0x29, KVAL_DEC = 0x29, FS_SPD = 0x027)

init (default: True) reset driver to initial values

ACC (default: 0x00A) Acceleration speed

DEC (default: 0x00A) Acceleration speed

stall_th (default: 2030mA) Stall current treshold in mA, maximal value is ******

ocd_th (default: 3380mA) Over current treshold in mA, maximal value is ******

KVAL_HOLD (default: 0x29)

KVAL_RUN(default: 0x29)

KVAL_ACC(default: 0x29)

KVAL_DEC(default: 0x29)

FS_SPD(default: 0x29)

MaxSpeed

def MaxSpeed(self, speed)

Write maximal speed to driver

speed (range: 15.25 - 1560) Maximal speed value in stpes/s

GoTo

def GoTo(self, abspos)

Brings motor into ABS_POS position (minimum path)

GoToDir

def GoToDir(self, direction, abspos)

Brings motor into ABS_POS position forcing DIR direction

Installation

cd ~/repos
git clone [email protected]:MLAB-project/axis.git
cd axis
sudo python setup.py develop