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rINSTCONTROL/@MyTpg/MyTpg.m
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MyTpg.m
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% Class for communication with Pfeiffer TPG single and dual pressure gauge
% controllers.
% Do not use visa communication objects with this instrument
% Tested with TPG 262 and 362.
classdef MyTpg < MyInstrument
properties (Constant=true)
% Named constants for communication
ETX = char(3); % end of text
CR = char(13); % carriage return \r
LF = char(10); %#ok<CHARTEN> % line feed \n
ENQ = char(5); % enquiry
ACK = char(6); % acknowledge
NAK = char(21); % negative acknowledge
end
properties (SetAccess=protected, GetAccess=public)
pressure1 = 0; % numeric values of pressure
pressure2 = 0;
stat1;
stat2;
gauge_id1;
gauge_id2;
pressure_unit = '';
end
properties (Dependent=true)
pressure_str1; % display string with measurement unit
pressure_str2;
end
methods (Access=public)
function this = MyTpg(interface, address, varargin)
this@MyInstrument(interface, address, varargin{:});
end
% read pressure from a single channel or both channels at a time
function p_arr = readPressure(this)
query(this.Device,['PRX',this.CR,this.LF]);
str = query(this.Device,this.ENQ);
% Extract pressure and gauge status from reading.
arr = sscanf(str,'%i,%e,%i,%e');
p_arr=transpose(arr(2:2:end));
this.pressure1 = p_arr(1);
this.pressure2 = p_arr(2);
% Status codes:
% 0 –> Measurement data okay
% 1 –> Underrange
% 2 –> Overrange
% 3 –> Sensor error
% 4 –> Sensor off (IKR, PKR, IMR, PBR)
% 5 –> No sensor (output: 5,2.0000E-2 [hPa])
% 6 –> Identification error
this.stat1 = gaugeStatusFromCode(this, arr(1));
this.stat2 = gaugeStatusFromCode(this, arr(3));
end
function pu = readPressureUnit(this)
query(this.Device,['UNI',this.CR,this.LF]);
str = query(this.Device,this.ENQ);
% Pressure units correspondence table:
% 0 –> mbar/bar
% 1 –> Torr
% 2 –> Pascal
% 3 –> Micron
% 4 –> hPascal (default)
% 5 –> Volt
pu_code = sscanf(str,'%i');
pu = pressureUnitFromCode(this, pu_code);
this.pressure_unit = pu;
end
function id_list = readGaugeId(this)
query(this.Device,['TID',this.CR,this.LF]);
str = query(this.Device,this.ENQ);
id_list = deblank(strsplit(str,{','}));
this.gauge_id1 = id_list{1};
this.gauge_id2 = id_list{2};
end
function p_arr = readAllHedged(this)
openDevice(this);
try
% Try opening device before each reading as unclarified
% spontaneous closing of the device was observed
p_arr = readPressure(this);
readPressureUnit(this);
readGaugeId(this);
catch
p_arr = [0,0];
warning('Error while communicating with gauge controller')
end
closeDevice(this);
end
% Re-define readHeader function
function HdrStruct=readHeader(this)
readAllHedged(this);
HdrStruct = struct();
HdrStruct.pressure1.value = this.pressure1;
HdrStruct.pressure1.str_spec = '%e';
HdrStruct.pressure2.value = this.pressure2;
HdrStruct.pressure2.str_spec = '%e';
HdrStruct.stat1.value = this.stat1;
HdrStruct.stat1.str_spec = '%s';
HdrStruct.stat2.value = this.stat2;
HdrStruct.stat2.str_spec = '%s';
HdrStruct.gauge_id1.value = this.gauge_id1;
HdrStruct.gauge_id1.str_spec = '%s';
HdrStruct.gauge_id2.value = this.gauge_id2;
HdrStruct.gauge_id2.str_spec = '%s';
HdrStruct.pressure_unit.value = this.pressure_unit;
HdrStruct.pressure_unit.str_spec = '%s';
end
% Attempt communication and identification of the device
function [str, msg]=idn(this)
was_open=isopen(this);
try
openDevice(this);
query(this.Device,['AYT',this.CR,this.LF]);
[str,~,msg]=query(this.Device,this.ENQ);
catch ErrorMessage
str='';
msg=ErrorMessage.message;
end
this.idn_str=str;
% Leave device in the state it was in the beginning
if ~was_open
try
closeDevice(this);
catch
end
end
end
function code_list = turnGauge(this)
query(this.Device,['SEN',char(1,1),this.CR,this.LF]);
str = query(this.Device,this.ENQ);
code_list = deblank(strsplit(str,{','}));
end
% Convert numerical code for gauge status to a string
function str = gaugeStatusFromCode(~, code)
switch int8(code)
case 0
str = 'Measurement data ok';
case 1
str = 'Underrange';
case 2
str = 'Overrange';
case 3
str = 'Sensor error';
case 4
str = 'Sensor off';
case 5
str = 'No sensor';
case 6
str = 'Identification error';
otherwise
str = '';
warning('Unknown gauge status code %i', code);
end
end
% Convert numerical code for pressure unit to a string
function str = pressureUnitFromCode(~, code)
switch int8(code)
case 0
str = 'mbar';
case 1
str = 'Torr';
case 2
str = 'Pa';
case 3
str = 'Micron';
case 4
str = 'hPa';
case 5
str = 'Volt';
otherwise
str = '';
warning('unknown pressure unit, code=%i',pu_num)
end
end
end
%% Get functions
methods
function p_str = get.pressure_str1(this)
p_str = sprintf('%.2e %s', this.pressure1, this.pressure_unit);
end
function p_str = get.pressure_str2(this)
p_str = sprintf('%.2e %s', this.pressure2, this.pressure_unit);
end
end
end
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