Class: RbVisa::Session

Inherits:
Object
  • Object
show all
Defined in:
lib/rb_visa/io.rb,
lib/rb_visa/session.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(address, &block) ⇒ Session

Returns a new instance of Session.



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# File 'lib/rb_visa/session.rb', line 7

def initialize address, &block
  mem = FFI::MemoryPointer.new :uint32, 1
  check VISA::viOpenDefaultRM mem
  puts "ressource manager opened"
  @rm = mem.read_uint32
  @address = address
  check VISA::viOpen( @rm, @address, VISA::VI_NULL, VISA::VI_NULL, mem)
  puts "session opened"
  @session = mem.read_uint32
  
  @string_buffer_length = 126
  @string_buffer = FFI::MemoryPointer.new :char, @string_buffer_length
  
  self.instance_eval &block if block
  self
end

Instance Attribute Details

#address ⇒ Object (readonly)

Returns the value of attribute address.



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# File 'lib/rb_visa/session.rb', line 5

def address
  @address
end

#rm ⇒ Object (readonly)

Returns the value of attribute rm.



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# File 'lib/rb_visa/session.rb', line 5

def rm
  @rm
end

#session ⇒ Object (readonly)

Returns the value of attribute session.



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# File 'lib/rb_visa/session.rb', line 5

def session
  @session
end

#status ⇒ Object (readonly)

Returns the value of attribute status.



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# File 'lib/rb_visa/session.rb', line 5

def status
  @status
end

Class Method Details

.release(object) ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 29

def self.release object
  object.close
end

Instance Method Details

#<<(command) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 29

def << command
  self.write command
end

#[](name) ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 62

def [] name
  mem = FFI::MemoryPointer.new :uint32, 1
  name = VISA.const_get(name) if name.is_a? Symbol 
  check VISA::viGetAttribute( @session, name, mem )
  return mem.read_uint32   
end

#[]=(name, value) ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 69

def []= name, value
  name  = VISA.const_get(name)  if name.is_a? Symbol 
  value = VISA.const_get(value) if value.is_a? Symbol 
  check VISA::viSetAttribute( @session, name, value )
end

#buffer(params = {}) ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 55

def buffer params = {}      
  VISA::Buffer.each_pair{ |buf,mask|
    check VISA::viSetBuf( @session, mask, params[buf] ) if params[buf] && params[buf] > 0
  } if params.is_a? Hash
  self
end

#buffer_grow(size) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 5

def buffer_grow size
  if size > @string_buffer_length
    @string_buffer = FFI::MemoryPointer.new :char, size
    @string_buffer_length = size
  end     
end

#check(status) ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 33

def check status
  puts self.status? if 0 > (@status = status)
  self
end

#clear ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 45

def clear
  check VISA::viClear @session
  self
end

#close ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 24

def close
  check VISA::viClose @session
  check VISA::viClose @rm
end

#flush(mask_val = VISA::VI_READ_BUF_DISCARD) ⇒ Object 



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# File 'lib/rb_visa/session.rb', line 50

def flush mask_val = VISA::VI_READ_BUF_DISCARD
  check VISA::viFlush @session, mask_val
  self
end

#id? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rb_visa/io.rb', line 37

def id?
  query "*idn?"   
end

#mread_into(chunk, &next_buffer) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 67

def mread_into chunk, &next_buffer   
  total = 0
  (self.parse / chunk).times do 
    VISA::viRead @session, next_buffer.call, chunk, @read_count  
puts "mread read count %i" % @read_count.read_uint32 
    total += @read_count.read_uint32
  end
  total
end

#mread_to(chunk, &handle_data) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 77

def mread_to chunk, &handle_data
  buffer_grow.chunk
  total = 0
  (self.parse / chunk).times do 
    VISA::viRead @session, @string_buffer, chunk, @read_count   
    handle_data.call @string_buffer.read_array_of_char chunk        
    total += @read_count.read_uint32
  end 
end

#parse ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 41

def parse
  @read_count ||= FFI::MemoryPointer.new :uint32, 1     
  
  comp   = "#".bytes.first
  offset = '0'.bytes.first
   
  #find beginning of header      
  while true
     check VISA::viRead @session, @string_buffer, 1, @read_count
     break if comp == @string_buffer.read_char
  end
  
  #read the size of the header tag
  check VISA::viRead @session, @string_buffer, 1, @read_count
  data_size_tag_size = @string_buffer.read_char - offset
#puts "data_size_tag size: %i" % data_size_tag_size
  
  #read the header tag and parse into an int
  check VISA::viRead @session, @string_buffer, data_size_tag_size, @read_count    
  size = @string_buffer.read_array_of_char(data_size_tag_size).map{ |c|
    c - offset
  }.join.to_i     
puts "data size: %i" % size    
  size
end

#query(command) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 33

def query command
  self.write(command).read
end

#read(bytes = @string_buffer_length) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 21

def read bytes = @string_buffer_length
  buffer_grow bytes
  @read_count ||= FFI::MemoryPointer.new :uint32, 1     
  check VISA::viRead @session, @string_buffer, bytes, @read_count
#puts "read count %i" % @read_count.read_uint32
  @string_buffer.read_string(@read_count.read_uint32).chomp
end

#status? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/rb_visa/session.rb', line 38

def status?
puts "error code #{@status} for #{@session ||@rm}"
  @error_buffer ||= FFI::MemoryPointer.new :char, 256
  VISA::viStatusDesc @session||@rm, @status, @error_buffer
  @error_buffer.read_string
end

#write(command) ⇒ Object 



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# File 'lib/rb_visa/io.rb', line 12

def write command
  buffer_grow command.length
  @string_buffer.write_string command
  @read_count ||= FFI::MemoryPointer.new :uint32, 1     
  check VISA::viWrite @session, @string_buffer, command.length, @read_count      
#puts "write count %i" % @read_count.read_uint32
  self     
end