pyjanssen

An object-oriented Python library for interfacing with the MCM module by Janssen Precision Engineering via cacli.exe (provided on the Janssen website). Implements all functions except autocalibration (as it is interactive).

Usage

Linear positioner import syntax: from pyjanssen import MCM, FORWARD, BACKWARD

Rotational positioner import syntax: from pyjanssen import MCM, CW, CCW

Class MCM provides an object-oriented wrapper for cacli.exe provided by Janssen Precision Engineering for control of their low temperature piezoelectric positioners

Example usage:

from pyjanssen import MCM, FORWARD, BACKWARD

m = MCM() # connect to the Janssen MCM using cacli.exe in current directory
m.move(1, FORWARD) # moves in positive direction
m.move(2, BACKWARD, frequency=10, step_size=50, temperature=293, steps=100, profile='PROFILE1') # moves in negative direction; sets new frequency, step_size, temperature, steps, and profile config
print(m.get_position(1)) # ask the MCM for the position of axis 1 (requires OEM2 module)

API Reference

MCM(device=None, **kwargs)

arguments: *device (default None) to specify specific MCM module if multiple returns: MCM instance

kwargs: exe (string) to specify path to cacli.exe if not in current directory server (bool) to specify use of cacli.exe in server mode (good for fast command responses) verbose (bool) to output commands and responses from cacli.exe for debugging

autocalibrate(self, address, channel, **kwargs)

Not implemented (needs input/output)

disable_servodrive(self)

returns: dictionary of STATUS

enable_servodrive(self, pgain=300, **kwargs)

arguments: *pgain (default 300) returns: dictionary of STATUS

uses values from channel 1 when setting TEMP, TYPE

frequency(self, address)

arguments: address returns: frequency for given address

get_description(self, address, **kwargs)

arguments: address returns: dictionary of Version and Available Channels

kwargs: force command to run ignoring servodrive gets module information

get_information(self, address, channel='1', **kwargs)

arguments: address, *channel (default 1) returns: dictionary of TYPE and TAG

kwargs: force command to run ignoring servodrive

gets positioner information

get_position(self, address, channel=1, **kwargs)

arguments: address, *channel (default 1) returns: position (integer)

kwargs: force command to run ignoring servodrive

get_position_raw(self, address, channel=1, **kwargs)

arguments: address, *channel (default 1) returns: raw encoder value (integer)

kwargs: force command to run ignoring servodrive

returns 'rvl' value from POS command

get_status(self, address, **kwargs)

arguments: address returns: dictionary of FAILSAFE STATE and STATUS

kwargs: force command to run ignoring servodrive

gets status of address

move(self, address, direction, channel=1, **kwargs)

arguments: address, direction, *channel (default 1), **kwargs returns: dictionary of STATUS

kwargs: frequency, step_size, temperature, steps, profile

takes address of module to move and direction (FORWARD, BACKWARD) as well as optional channel if using CADM module (not CADM2!) plus optional kwargs to set frequency/step size/temperature (these values are retained)

profile(self, address)

arguments: address returns: profile for given address reset_position(self, address, channel=1, **kwargs) arguments: address, *channel (default 1) returns: string

kwargs: force command to run ignoring servodrive

resets the position counter to 0

select_analogue_input(self, address, direction, channel=1, **kwargs)

arguments: address, direction, *channel (default 1), **kwargs returns: dictionary of STATUS

kwargs: frequency, step_size, temperature, steps, profile

!! NOTE !! From the manual: The CADM2 module will perform an ‘automatic zero calibration’ upon power on to make sure the connected actuator will not move at an input voltage of o (zero) [V]14. However, this means that it is required to hold the input at 0 (zero) [V] during power on of the module (do not let the input float).

servodrive_emergency_stop(self, **kwargs)

returns: dictionary of STATUS servodrive_find_end_stops(self, direction, filter, zero, **kwargs) arguments: direction, filter, zero returns: dictionary of STATUS

direction: FORWARD or BACKWARD filter: integer, 1-20, velocity polling delay (relative) zero: boolean, reset position after completion

servodrive_go_to(self, pos1=0, pos2=0, pos3=0, **kwargs)

arguments: *pos1, *pos2, *pos3 (set 0 if not connected) returns: dictionary of STATUS servodrive_status_position(self, **kwargs) returns: dictionary of STATUS, ENABLED, BUSY, POS1, POS2, POS3, ERR1, ERR2, ERR3

ENABLED is 0 (disabled), 1 (enabled), 2 (find end stop active) BUSY is 1 if minimizing error between setpoint and current point POSx is current position information for each ERRx is the difference between current position and target position

set_frequency(self, address, frequency)

arguments: address, frequency

in Hz, between 0 and 600

set_profile(self, address, profile)

arguments: address, profile

name of controller profile

set_step_size(self, address, step_size)

arguments: address, step_size

in %, between 0 and 100

set_steps(self, address, steps)

arguments: address, steps

number, between 0 and 50000

set_temperature(self, address, temperature)

arguments: address, temperature

in K, between 0 and 300

step_size(self, address)

arguments: address returns: step_size for given address

steps(self, address)

arguments: address returns: steps for given address

stop(self, address, **kwargs)

arguments: address returns: dictionary of STATUS

kwargs: force command to run ignoring servodrive

stops movement (Flexidrive only)

temperature(self, address)

arguments: address returns: temperature for given address