first tries with uniax stick

secop_psi/dpm.py

@@ -0,0 +1,145 @@
+#  -*- coding: utf-8 -*-
+# *****************************************************************************
+#
+# This program is free software; you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free Software
+# Foundation; either version 2 of the License, or (at your option) any later
+# version.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+# FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
+# details.
+#
+# You should have received a copy of the GNU General Public License along with
+# this program; if not, write to the Free Software Foundation, Inc.,
+# 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+# Module authors:
+#   ...
+#
+# *****************************************************************************
+
+from secop.core import Readable, Parameter, FloatRange, BoolType, StringIO, HasIodev, IntRange, Done
+
+
+class DPM3IO(StringIO):
+    end_of_line = '\r'
+    timeout = 3
+    identification = [('*1R135', '01')]
+
+
+def hex2float(hexvalue, digits):
+    value = int(hexvalue, 16)
+    if value >= 0x800000:
+        value -= 0x1000000
+    return value / (10 ** digits)
+
+
+def float2hex(value, digits):
+    intvalue = int(round(value * 10 ** digits,0))
+    if intvalue < 0:
+        intvalue += 0x1000000
+    return '%06X' % intvalue
+
+
+class DPM3(HasIodev, Readable):
+    OFFSET = 0x8f
+    SCALE = 0x8c
+    
+    MAGNITUDE = {'1': 1, '2': 10, '3': 100, '4': 1e3, '5': 1e4, '6': 1e5,
+             '9':-1, 'A':-10, 'B':-100, 'C':-1e3, 'D':-1e4, 'E':-1e5}
+    
+    iodevClass = DPM3IO
+    
+    digits = Parameter('number of digits for value', IntRange(0, 5), initwrite=True, readonly=False)
+    value = Parameter(unit='N')
+
+    offset = Parameter('', FloatRange(-1e5, 1e5), readonly=False, poll=True)
+    
+    #Note: we have tro treat the units properly.
+    """ We got an output of 150 for 10N. The maximal force we want to deal with is 100N,
+        thus a maximl output of 1500. 10=150/f 
+    """
+    scale_factor  = Parameter('', FloatRange(-1e5, 1e5, unit='input_units/N'), readonly=False, poll=True)
+    
+    def query(self, adr, value=None):
+        if value is not None:
+            if adr == self.SCALE:
+                absval = abs(value)
+                for nibble, mag in self.MAGNITUDE.items():
+                    if 10000 <= round(value * mag, 0) <= 99999:
+                        break
+                else:
+                    # not suitable range found
+                    if absval >= 99999.5:  # overrange
+                        raise ValueError('%s is out of range' % value)
+                    # underrange: take lowest
+                    nibble = '9'  if value < 0 else '1'
+                    mag = self.MAGNITUDE[nibble]
+                hex_val = nibble + '%05X' % int(round(value * mag, 0))
+                if hex_val[1:] == '00000':
+                    raise ValueError('scale factor can not be 0', value)
+            else:
+                hex_val = float2hex(value, self.digits)
+            cmd = '*1F3%02X%s\r' % (adr, hex_val)
+        else:
+            cmd = ""
+        cmd = cmd + '*1G3%02X' % adr
+        hexvalue = self._iodev.communicate(cmd)
+        print(cmd, hexvalue)
+        if adr == self.SCALE:
+            mag = self.MAGNITUDE[hexvalue[0:1]]
+            value = int(hexvalue[1:], 16)
+            return value/mag
+        else:
+            return hex2float(hexvalue, self.digits)
+    
+    def write_digits(self, value):
+        # value defines the number of digits
+        back_value=self._iodev.communicate('*1F135%02X\r*1G135' % (value + 1))
+        self.digits = int(back_value,16) - 1
+        # realculate proper scale and offset
+        self.write_scale_factor(self.scale_factor)
+        self.write_offset(self.offset)
+        return Done
+    
+    def read_digits(self):
+        back_value = self._iodev.communicate('*1G135')
+        return int(back_value,16) - 1
+ 
+    def read_value(self):
+        value = self._iodev.communicate('*1B1')
+        return float(value)
+    
+    def read_offset(self):
+        reply = self.query(self.OFFSET)
+        return reply
+            
+    def write_offset(self, value):
+        return self.query(self.OFFSET, value)
+
+    def read_scale_factor(self):
+        reply = self.query(self.SCALE)
+        return float(reply) / 10 ** self.digits
+
+    def write_scale_factor(self, value):
+        reply = self.query(self.SCALE, value * 10 ** self.digits)
+        return float(reply) / 10 ** self.digits
+      
+            
+        
+        
+    
+        
+    
+    
+
+        
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+