Linkam TMS91/TMS94 temperature stages

Kindly contributed by Filip Dominec.

rep/linkam/tms.py

@@ -0,0 +1,87 @@
+import visa
+
+__all__ = ['TempStage', 'TMS91', 'TMS94']
+
+# Original code kindly contributed by Filip Dominec <dominecf@fzu.cz>
+# See http://www.fzu.cz/~dominecf/python/FDLabInstruments.py
+
+
+class TempStage(object, visa.SerialInstrument):
+    """Base class for Linkam temperature stages."""
+
+    def __init__(self, *args, **kwargs):
+        visa.SerialInstrument.__init__(self, *args, **kwargs)
+        self.term_chars = visa.CR
+        self.rate = 20
+
+    # Dummy context manager
+    def __enter__(self):
+        return self
+
+    def __exit__(self, type, value, traceback):
+        pass
+
+    @property
+    def temp(self):
+        """Temperature in deg C"""
+        raise NotImplementedError
+
+    @property
+    def status(self):
+        """Current status byte"""
+        raw_string = self.ask('T')
+        return ord(raw_string[0])
+
+    @property
+    def rate(self):
+        """Rate of temperature change (deg C/min); default is 20"""
+        return self._rate
+
+    @rate.setter
+    def rate(self, value):
+        self._rate = abs(value)
+
+
+class TMS91(TempStage):
+    def __init__(self, *args, **kwargs):
+        super(TMS91, self).__init__(*args, **kwargs)
+        # From Linkam91 manual: 9600 baud, 8 data bits, 1 stop bit, no parity,
+        # using an RTS / CTS handshake.
+        # Serial cable (linkam D25 -> serial D9) pins: 2-2 3-3 4-8 5-7 7-5;
+        # connect 6,4 of PC together.
+        self.baud_rate = 9600
+        self.timeout = 20
+
+    @property
+    def temp(self):
+        raw_string = self.ask('T')
+        return float(raw_string[1:])
+
+    @temp.setter
+    def temp(self, value):
+        self.write('R1{:d}'.format(self.rate))  # Sets rate
+        self.write('L1{:d}'.format(value))  # Sets target temperature
+        self.write('R20')  # End of current profile
+        self.write('S')  # Starts action
+
+
+class TMS94(TempStage):
+    def __init__(self, *args, **kwargs):
+        super(TMS94, self).__init__(*args, **kwargs)
+        # From Linkam94 manual: 19200 baud, 8 data bits, 1 stop bit, no parity
+        # using an RTS / CTS handshake.
+        # All commands from the PC must end with a carriage return.
+        # NOTE: When probed at baud_rate=9600, this model freezes.
+        self.baud_rate = 19200
+        self.timeout = 3
+
+    @property
+    def temp(self):
+        raw_string = self.ask('T')
+        return int(raw_string[6:10], 16) / 10.0
+
+    @temp.setter
+    def temp(self, value):
+        self.write('R1{:04d}'.format(self.rate * 100))  # Sets rate
+        self.write('L1{:04d}'.format(value * 10))  # Sets target temperature
+        self.write('S')  # Starts action