From: W. Trevor King <wking@drexel.edu>
Date: Wed, 26 Nov 2008 20:19:29 +0000 (-0500)
Subject: Minor hack to z_piezo.py to support calibcant.config module.
X-Git-Tag: 0.2~5
X-Git-Url: http://git.tremily.us/?a=commitdiff_plain;h=c732ed6778bbe6025d6a0b89ca87bd34ab90800a;p=pypiezo.git

Minor hack to z_piezo.py to support calibcant.config module.
---

diff --git a/z_piezo.py b/z_piezo.py
index ceb4d90..6b1e539 100644
--- a/z_piezo.py
+++ b/z_piezo.py
@@ -34,6 +34,13 @@ BASE_FIG_NUM = 50
 LOG_RAMPS = False
 LOG_DIR = '/home/wking/rsrch/data/z_piezo'
 
+# Hackish defaults for the calibcant.config module
+DEFAULT_GAIN = 20 # Vpiezo / Voutput
+DEFAULT_SENSITIVITY = 7.41 # nm_surface/Volt_piezo
+DEFAULT_ZERO_PHOTODIODE_BITS = 2**15
+DEFAULT_VPHOTO_IN_2_VOLTS = lambda vbits : (vbits-DEFAULT_ZERO_PHOTODIODE_BITS)/3276.8
+DEFAULT_VZP_OUT_2_VOLTS   = lambda vbits : (vbits-DEFAULT_ZERO_PHOTODIODE_BITS)/3276.8
+
 DEFAULT_ZP_CHAN = 0
 DEFAULT_ZP_MON_CHAN = 1
 DEFAULT_DEF_CHAN = 0
@@ -44,8 +51,16 @@ if USE_ABCD_DEFLECTION :
     #  C D
     # looking in along the laser
 
-import pycomedi.single_aio as single_aio
-import pycomedi.simult_aio as simult_aio
+class NoComedi (ImportError):
+    "Missing comedi.  Don't initialize a z_piezo instance."
+    pass
+
+try:
+    import pycomedi.single_aio as single_aio
+    import pycomedi.simult_aio as simult_aio
+    HAS_COMEDI = True
+except ImportError, e:
+    HAS_COMEDI = False
 
 from numpy import array, arange, ones, zeros, linspace, uint16, float, sin, pi
 from scipy.stats import linregress
@@ -66,8 +81,10 @@ class z_piezo :
     def __init__(self, zp_chan=DEFAULT_ZP_CHAN,
                  zp_mon_chan=DEFAULT_ZP_MON_CHAN,
                  def_chan=DEFAULT_DEF_CHAN) :
-        self.sensitivity = 7.41 # nm_surface/Volt_piezo
-        self.gain = 20 # Vpiezo / Voutput
+        if HAS_COMEDI is not True:
+            raise NoComedi
+        self.sensitivity = DEFAULT_SENSITIVITY
+        self.gain = DEFAULT_GAIN
         self.nm2Vout = self.sensitivity * self.gain # nm_surface / V_output
         self.chan_info = _chan_info(zp_chan, zp_mon_chan, def_chan)