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work in progress MKS 901P vacuum transducer sensor library and command-line program.
"""
usage: mks_901p.py [-h] [--find_baud] [--baud BAUD] [-unit] serial_port
positional arguments:
serial_port the Windows COM port or path to a linux serial port
optional arguments:
-h, --help show this help message and exit
--find_baud tries to access the sensor over all supported baud rates,
prints which is successful
--baud BAUD baud rate to connect with, defaults to 9600 (901p factory
default)
-unit print pressure unit with each reading
"""
# xxx = Transducer communication address (001 to 253. Broadcast addresses: 254, 255)
baud_supported = [4800, 9600, 19200, 38400, 57600, 115200, 230400]
commands = {
'Communication information': {
'get_baud_rate': {
'Command': '@{}BR?;FF',
'Response': '@xxxACK9600;FF',
'Explanation': 'Communication baud rate (4800, 9600, 19200, 38400, 57600, 115200,230400)'
},
'get_address': {
'Command': '@{}AD?;FF',
'Response': '@xxxACK253;FF',
'Explanation': 'Transducer communication address (001 to 253)'
},
'get_comms_delay': {
'Command': '@{}RSD?;FF',
'Response': '@xxxACKON;FF',
'Explanation': 'Communication delay between receive and transmit sequence.'
}
},
'Pressure reading': {
'pirani': {
'Command': '@{}PR1?;FF',
'Response': '@xxxACK1.23E-3;FF',
'Explanation': 'MicroPirani sensor pressure as 3 digit floating point value.'},
'piezo': {
'Command': '@{}PR2?;FF',
'Response': '@xxxACK-7.60E+2;FF',
'Explanation': 'Piezo differential sensor pressure as 3 digit floating point value.'},
'combined_3_digit': {
'Command': '@{}PR3?;FF',
'Response': '@xxxACK1.23E-3;FF',
'Explanation': 'Combined reading as 3 digit floating point value.'},
'combined_4_digit': {
'Command': '@{}PR4?;FF',
'Response': '@xxxACK1.234E-3;FF',
'Explanation': 'Combined reading as 4 digit floating point value.'}
},
'Setpoint information': {
'get_setpoint_1_status': {
'Command': '@{}SS1?;FF',
'Response': '@xxxACKSET;FF',
'Explanation': 'Set point relay 1-3 status (SET=Relay energized / CLEAR=Relay deenergized'},
'get_setpoint_2_status': {
'Command': '@{}SS2?;FF',
'Response': '@xxxACKSET;FF',
'Explanation': 'Set point relay 1-3 status (SET=Relay energized / CLEAR=Relay deenergized'},
'get_setpoint_3_status': {
'Command': '@{}SS3?;FF',
'Response': '@xxxACKSET;FF',
'Explanation': 'Set point relay 1-3 status (SET=Relay energized / CLEAR=Relay deenergized'},
'get_setpoint_1': {
'Command': '@{}SP1?;FF',
'Response': '@xxxACK1.00E-2;FF',
'Explanation': 'Set point 1-3 switch value.'},
'get_setpoint_2': {
'Command': '@{}SP2?;FF',
'Response': '@xxxACK1.00E-2;FF',
'Explanation': 'Set point 1-3 switch value.'},
'get_setpoint_3': {
'Command': '@{}SP3?;FF',
'Response': '@xxxACK1.00E-2;FF',
'Explanation': 'Set point 1-3 switch value.'},
'get_hysteresis_1': {
'Command': '@{}SH1?;FF',
'Response': '@xxxACK1.10E-2;FF',
'Explanation': 'Set point 1-3 hystereses switch value.'},
'get_hysteresis_2': {
'Command': '@{}SH2?;FF',
'Response': '@xxxACK1.10E-2;FF',
'Explanation': 'Set point 1-3 hystereses switch value.'},
'get_hysteresis_3': {
'Command': '@{}SH3?;FF',
'Response': '@xxxACK1.10E-2;FF',
'Explanation': 'Set point 1-3 hystereses switch value.'},
'get_setpoint_1_enabled': {
'Command': '@{}EN1?;FF',
'Response': '@xxxACKDIFF;FF',
'Explanation': 'Set point 1-3 enable status ( OFF, DIFF=Piezo differential or ABS=Absolute Piezo)'},
'get_setpoint_2_enabled': {
'Command': '@{}EN2?;FF',
'Response': '@xxxACKDIFF;FF',
'Explanation': 'Set point 1-3 enable status ( OFF, DIFF=Piezo differential or ABS=Absolute Piezo)'},
'get_setpoint_3_enabled': {
'Command': '@{}EN3?;FF',
'Response': '@xxxACKDIFF;FF',
'Explanation': 'Set point 1-3 enable status ( OFF, DIFF=Piezo differential or ABS=Absolute Piezo)'},
'get_setpoint1_relay_direction': {
'Command': '@{}SD1?;FF',
'Response': '@xxxACKBELOW;FF',
'Explanation': 'Set point relay direction (ABOVE or BELOW) If set to above relay will be energized above setpoint value. If set to below relay will be energized below setpoint value.'},
'get_setpoint2_relay_direction': {
'Command': '@{}SD2?;FF',
'Response': '@xxxACKBELOW;FF',
'Explanation': 'Set point relay direction (ABOVE or BELOW) If set to above relay will be energized above setpoint value. If set to below relay will be energized below setpoint value.'},
'get_setpoint3_relay_direction': {
'Command': '@{}SD3?;FF',
'Response': '@xxxACKBELOW;FF',
'Explanation': 'Set point relay direction (ABOVE or BELOW) If set to above relay will be energized above setpoint value. If set to below relay will be energized below setpoint value.'},
'get_setpoint_safety_delay': {
'Command': '@{}SPD?;FF',
'Response': '@xxxACKON;FF',
'Explanation': 'Setpoint safety delay'}
},
'Transducer information': {
'get_model': {
'Command': '@{}MD?;FF',
'Response': '@xxxACK901P;FF',
'Explanation': 'Model number (901P)'},
'get_devicetype': {
'Command': '@{}DT?;FF',
'Response': '@xxxACKLoadlock;FF',
'Explanation': 'Device type name (MicroPirani)'},
'get_mfg': {
'Command': '@{}MF?;FF',
'Response': '@xxxACKMKS;FF',
'Explanation': 'Manufacturer name (MKS)'},
'get_hw_version': {
'Command': '@{}HV?;FF',
'Response': '@xxxACKA;FF',
'Explanation': 'Hardware version'},
'get_fw_version': {
'Command': '@{}FV?;FF',
'Response': '@xxxACK1.00;FF',
'Explanation': 'Firmware version'},
'get_serial_num': {
'Command': '@{}SN?;FF',
'Response': '@xxxACK08350123456;FF',
'Explanation': 'Serial number'},
'get_switch': {
'Command': '@{}SW?;FF',
'Response': '@xxxACKON;FF',
'Explanation': 'Switch enable'},
'get_time_on': {
'Command': '@{}TIM?;FF',
'Response': '@xxxACK12345;FF',
'Explanation': 'Time on (hours of operation )'},
'get_pirani_temp': {
'Command': '@{}TEM?;FF',
'Response': '@xxxACK2.50E+1;FF',
'Explanation': 'MicroPirani sensor temperature'},
'get_usertext': {
'Command': '@{}UT?;FF',
'Response': '@xxxACKVACUUM1;FF',
'Explanation': 'User programmed text string'},
'get_status': {
'Command': '@{}T?;FF',
'Response': '@xxxACKO;FF',
'Explanation': 'Transducer status check'}
},
'Calibration and adjustment information': {
'get_pressure_unit': {
'Command': '@{}U?;FF',
'Response': '@xxxACKTORR;FF',
'Explanation': 'Pressure unit setup (Torr, mbar or Pascal)'},
'get_calibration_gas': {
'Command': '@{}GT?;FF',
'Response': '@xxxACKNITROGEN;FF',
'Explanation': 'MicroPirani sensor calibration gas (Nitrogen, Air, Argon, Helium, Hydrogen, H2O, Neon, CO2, Xenon)'},
'get_factory_diff_zero_point': {
'Command': '@{}VAC?;FF',
'Response': '@xxxACK5.12E-5;FF',
'Explanation': 'Provides delta pressure value between current vacuum zero adjustment and factory calibration.'},
'get_factory_diff_atmosphere': {
'Command': '@{}ATM?;FF',
'Response': '@xxxACK1.22E+1;FF',
'Explanation': 'Provides delta pressure value between current atmospheric adjustment and factory calibration.'},
'get_analog_out_1': {
'Command': '@{}AO1?;FF',
'Response': '@xxxACK10;FF',
'Explanation': 'Analog voltage output 1: Pressure assignment and calibration. (first digit is pressure assignment, second and third digit is calibration)'},
'get_analog_out_2': {
'Command': '@{}AO2?;FF',
'Response': '@xxxACK10;FF',
'Explanation': 'Analog voltage output 2: Pressure assignment and calibration. (first digit is pressure assignment, second and third digit is calibration)'}
},
'Setpoint setup and configuration': {
'set_setpoint_1':{
'Command': '@{}SP1!2.00E+1;FF',
'Response': '@xxxACK2.00E+1;FF',
'Explanation': 'Set point 1-3 switch value.'},
'set_setpoint_2':{
'Command': '@{}SP2!2.00E+1;FF',
'Response': '@xxxACK2.00E+1;FF',
'Explanation': 'Set point 1-3 switch value.'},
'set_setpoint_3':{
'Command': '@{}SP3!2.00E+1;FF',
'Response': '@xxxACK2.00E+1;FF',
'Explanation': 'Set point 1-3 switch value.'},
'set_hysteresis_1':{
'Command': '@{}SH1!5.00E+1;FF',
'Response': '@xxxACK5.00E+1;FF',
'Explanation': 'Set point 1-3 hysteresis switch value.'},
'set_hysteresis_2':{
'Command': '@{}SH2!5.00E+1;FF',
'Response': '@xxxACK5.00E+1;FF',
'Explanation': 'Set point 1-3 hysteresis switch value.'},
'set_hysteresis_3':{
'Command': '@{}SH3!5.00E+1;FF',
'Response': '@xxxACK5.00E+1;FF',
'Explanation': 'Set point 1-3 hysteresis switch value.'},
'enable_setpoint_1':{
'Command': '@{}EN1!ON;FF',
'Response': '@xxxACKON;FF',
'Explanantion': 'Set point 1-3 enable status (ON or OFF)'},
'enable_setpoint_2':{
'Command': '@{}EN2!ON;FF',
'Response': '@xxxACKON;FF',
'Explanantion': 'Set point 1-3 enable status (ON or OFF)'},
'enable_setpoint_3':{
'Command': '@{}EN3!ON;FF',
'Response': '@xxxACKON;FF',
'Explanantion': 'Set point 1-3 enable status (ON or OFF)'},
'set_setpoint1_relay_direction':{
'Command': '@{}SD1!BELOW;FF',
'Response': '@xxxACKBELOW;FF',
'Explanation': 'Set point relay direction (ABOVE or BELOW). If set to above relay will be energized above setpoint value. If set to below relay will be energized below setpoint value.'},
'set_setpoint2_relay_direction':{
'Command': '@{}SD2!BELOW;FF',
'Response': '@xxxACKBELOW;FF',
'Explanation': 'Set point relay direction (ABOVE or BELOW). If set to above relay will be energized above setpoint value. If set to below relay will be energized below setpoint value.'},
'set_setpoint3_relay_direction':{
'Command': '@{}SD3!BELOW;FF',
'Response': '@xxxACKBELOW;FF',
'Explanation': 'Set point relay direction (ABOVE or BELOW). If set to above relay will be energized above setpoint value. If set to below relay will be energized below setpoint value.'},
'set_setpoint_safety_delay':{
'Command': '@{}SPD!ON;FF',
'Response': '@xxxACKON;FF',
'Explanation': 'Setpoint safety delay (prevent pulse trig of setpoint)'}
},
'Communication setup': {
'set_baud_rate': {
'Command': '@{}BR!19200;FF',
'Response': '@xxxACK19200;FF',
'Explanation': 'Set communication Baud rate (4800, 9600, 19200, 38400, 57600, 115200, 230400)'},
'set_address': {
'Command': '@{}AD!123;FF',
'Response': '@xxxACK123;FF',
'Explanation': 'Set Transducer communication address (001 to 253)'},
'set_comms_delay': {
'Command': '@{}RSD!OFF;FF',
'Response': '@xxxACKOFF;FF',
'Explanation': 'Turn on or off communication delay between receive and transmit sequence.'}
},
'Calibration and adjustment': {
'set_pressure_unit': {
'Command': '@{}U!MBAR;FF',
'Response': '@xxxACKMBAR;FF',
'Explanation': 'Set pressure unit setup (Torr, mbar, Pascal)'},
'set_calibration_gas': {
'Command': '@{}GT!ARGON;FF',
'Response': '@xxxACKARGON;FF',
'Explanation': 'Set MicroPirani sensor calibration gas. (Nitrogen, Air, Argon, Helium, Hydrogen, H2O, Neon, CO2, Xenon)'},
'perform_pirani_zero_adjustment': {
'Command': '@{}VAC!;FF',
'Response': '@xxxACK;FF',
'Explanation': 'Executes MicroPirani zero adjustment'},
'perform_pirani_atmosphere_adjustment': {
'Command': '@{}ATM!7.60E+2;FF',
'Response': '@xxxACK;FF',
'Explanation': 'Executes MicroPirani full scale atmospheric adjustment.'},
'perform_piezo_absolute_adjustment': {
'Command': '@{}ATD!7.60E+2;FF',
'Response': '@xxxACK;FF',
'Explanation': 'Executes Piezo absolute reading at zero differential pressure.'},
'perform_piezo_differential_adjustment': {
'Command': '@{}ATZ;FF',
'Response': '@xxxACK;FF',
'Explanation': 'Executes Piezo differential zero adjustment'},
'set_analog_out_1': {
'Command': '@{}AO1!10;FF',
'Response': '@xxxACK10;FF',
'Explanation': 'Set analog voltage output 1 calibration.'},
'set_analog_out_2': {
'Command': '@{}AO1!10;FF',
'Response': '@xxxACK10;FF',
'Explanation': 'Set analog voltage output 2 calibration.'}
},
'Information setup': {
'set_user_tag':{
'Command': '@{}UT!LOADLOCK;FF',
'Response': '@xxxACKLOADLOCK;FF',
'Explanation': 'Set transducer user tag'
}
},
'User Switch': {
'set_userswitch_on_off': {
'Command': '@{}SW!ON;FF',
'Response': '@xxxACKON;FF',
'Explanation': 'Enable / disable user switch'
}
}
}
error_responses = [
['NAK Code', 'Error', 'description'],
['8', 'Zero adjustment at too high pressure', '@253VAC!;FF'],
['9', 'Atmospheric adjustment at too low pressure', '@253ATM!7.60;FF'],
['160', 'Unrecognized message', '@253S%;FF'],
['169', 'Invalid argument', '@253EN1!of;FF'],
['172', 'Value out of range', '@253SP1!5.00E+9;FF'],
['175', 'Command/query character invalid', '@253FV!;FF'],
['180', 'Not in setup mode (locked)', '-'],
]
# xxx = Transducer communication address (001 to 253. Broadcast addresses: 254, 255)
broadcast_address_1 = 254 # 254 WILL cause any listening sensors to reply
broadcast_address_2 = 255 # 255 will NOT cause any listening sensors to reply
DEBUG = False
import serial
class Mks901P(object):
def __init__(self, com_port_name, baud=9600):
self.com_port_name = com_port_name
if DEBUG:
print('creating new MKS 901p object with baud of {}'.format(baud))
self.serial_port = serial.Serial(com_port_name, baudrate=baud)
#self.serial_port.read()
self.pressure_unit = None
def get_pressure_unit(self, address=broadcast_address_1):
cmd = commands['Calibration and adjustment information']['get_pressure_unit']
expect = cmd['Response']
cmd = cmd['Command']
output = self.send_cmd(cmd, expect, address)
if output:
self.pressure_unit = output[1]
return self.pressure_unit
def get_pressure_combined_4_digit(self, address=broadcast_address_1, return_address=False):
cmd = commands['Pressure reading']['combined_4_digit']['Command']
expect = commands['Pressure reading']['combined_4_digit']['Response']
output = self.send_cmd(cmd, expect, address)
if output and not return_address:
return output[1]
return output
def send_cmd(self, cmd, expected_response, address):
cmd = cmd.format(address)
self.serial_port.write(bytes(cmd.encode()))
raw_data = self.serial_port.read(len(expected_response))
data = raw_data.decode()
if 'ACK' in data:
addr = data[data.index('@')+len('@'):data.index('ACK')]
value = data[data.index('ACK')+len('ACK'):].split(';')[0]
return (addr,value)
else:
if DEBUG:
print('no ACK received from cmd')
return None
import os
import sys
import time
this_files_path = os.path.abspath(__file__)
if __name__ == '__main__':
import argparse
parser = argparse.ArgumentParser()
parser.add_argument("serial_port", help='the Windows COM port or path to a linux serial port')
parser.add_argument("--find_baud", help='tries to access the sensor over all supported baud rates, prints which is successful', action="store_true")
parser.add_argument("--baud", help='baud rate to connect with, defaults to 9600 (901p factory default)', type=int)
parser.add_argument("-unit", help='print pressure unit with each reading', action="store_true")
args = parser.parse_args()
com_port = args.serial_port
if args.find_baud and not args.baud:
from subprocess import STDOUT, check_output, TimeoutExpired
for baud in baud_supported:
print("attempting to ask MKS 901p for it's baudrate using baudrate of {}".format(baud))
cmd = [sys.executable, this_files_path, com_port, '--find_baud', '--baud={}'.format(baud)]
try:
output = check_output(cmd, stderr=STDOUT, timeout=1)
if output:
output = output.decode().split(',')
output = [o.strip("() '\n") for o in output]
print('sensor ({}) replied with baudrate of ({})'.format(output[0], output[1]))
break
except TimeoutExpired:
pass
elif args.find_baud and args.baud:
if DEBUG:
print('setting up connection using baudrate of: {}'.format(args.baud))
m = Mks901P(com_port, args.baud)
cmd = commands['Communication information']['get_baud_rate']['Command']
expect = commands['Communication information']['get_baud_rate']['Response']
print(m.send_cmd(cmd, expect, broadcast_address_1))
else:
if args.baud:
m = Mks901P(com_port, args.baud)
else:
m = Mks901P(com_port)
unit = ''
if args.unit:
unit = ' {}'.format(m.get_pressure_unit())
while True:
print('{}{}'.format(m.get_pressure_combined_4_digit(), unit))
time.sleep(1)
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