class PtM3500a < Instrument
# multimeter
# PICOTEST M3500A

def instrument()
  @function="voltage:dc"
  @delay=0
  @count=1
end

def function(str="")
  strs=["voltage:ac", "voltage:dc", "resistance","fresistance",
	"current:ac","current:dc", "frequency","temperature",
	"period","diode","continuity"]
  #  command("sense:function",v,*str)
  if strs.include?(str)
    talk('sense:function "%s"'%str)
    @function=str
  else
    talk("sense:function?")
    @function=listen() # remove quote
  end
  @function
end
def range(v=nil)
  command("sense:%s:range"%@function,v,"min","max")
end
def rangeauto(v=nil)
  command("sense:%s:range:auto"%@function,v,"on","off")
end
def resolution(v=nil) #min is good resolution
  command("sense:%s:resolution"%@function,v,"min","max")
end
def cycle(v=nil) # measuring time in the unit of 1s/cycle of AC line
  command("sense:%s:nplcycles"%@function,v,"min","max") #0.02|0.1|1|10
end
def average(n=nil,v=nil,o=nil)
  o="on" if n
  n=command("sense:average:count",n,"min","max")
  v=command("sense:average:tcontrol",v,"mov","rep")
  o=command("sense:average:state",o,"on","off")
  [n,v,o]
end
def thermocouple(v=nil)
  command("sense:tcouple:type",v,*%w"E J K N R S T")
end
def unit(v=nil)
  command("sense:unit",v,"C","F","K")
end
#sense:tcouple:rjunction:rselect real|sim
def simulate(v=nil) #temperature reference
  command("sense:tcouple:simulated",v,"min","max")
end
def trigger(v=nil) #bus trigger, internal immediate mode, external mode
  command("trigger:source",v,"bus","imm","ext")
end
def delay(v=nil) #second
  @delay=command("trigger:delay",v,"min","max").to_f
end
def delayauto(v=nil)
  command("trigger:delay:auto",v,"on","off")
end

def measure() #sigle measurement
  talk("measure?")
  sleep @delay
  listen().to_s.sub(/^\w*/){""}.to_f
end
def read() # not stored in memory
  talk("read?")
  #trigger
  listen().to_s.sub(/^\w*/){""}.to_f
end

#TRIGger:COUNt <value>
def count(v=nil) #several measuremts in one trigger
  @count=command("sample:count",v).to_i
end
def initiate() # stored into memory
  talk("INITIATE")
end
def memory() # wait and read from memory
  sleep 0.01 while command("data:points",nil).to_f<@count
  talk("fetch?")
  listen(20*@count).split(/,/).map(&:to_f)
end
def point()
  command("data:points",nil)
end
def fetch()
  command("fetch",nil)
end

protected
def command(str="",v=nil,*strs)
 if String===v and v.to_s=~/^(#{strs*"|"})/i
  talk("%s %s"%[str,$1.upcase])
 elsif Numeric===v #Numeric===strs[0] and v
#  sign=(strs[0]==strs.max)?1:-1 #descending/ascending
#  v=v.to_f.abs
#  v=[strs.find_index{|vv|sign*vv.to_f<sign*v}.to_i-1,0].max
  talk("%s %e"%[str,v])
#  v=strs[v]
 else
  talk("%s?"%str)
#  v=strs[listen.to_f]
  v=listen()
 end
 v
end

end #class