windows interface for the PPMS driver

this runs on window systems only

Change-Id: I75ea9572981a4d6da2e5b371b709d613578a1e80
Reviewed-on: https://forge.frm2.tum.de/review/c/sine2020/secop/playground/+/21447
Tested-by: JenkinsCodeReview <bjoern_pedersen@frm2.tum.de>
Reviewed-by: Markus Zolliker <markus.zolliker@psi.ch>

secop_psi/ppmswindows.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python
+#  -*- 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:
+#   Markus Zolliker <markus.zolliker@psi.ch>
+# *****************************************************************************
+import threading
+
+try:
+    import pythoncom
+    import win32com.client
+except ImportError:
+    print("This Module only works with a pythoncom module on a MS Windows OS")
+    raise
+
+class Error(Exception):
+    pass
+
+class QDevice:
+    def __init__(self, classid):
+        self.threadlocal = threading.local()
+        self.classid = classid
+
+    def send(self, command):
+        try:
+            mvu = self.threadlocal.mvu
+        except AttributeError:
+            pythoncom.CoInitialize()
+            mvu = win32com.client.Dispatch(self.classid)
+            self.threadlocal.mvu = mvu
+        args = [
+            win32com.client.VARIANT(pythoncom.VT_BYREF | pythoncom.VT_BSTR, command),
+            win32com.client.VARIANT(pythoncom.VT_BYREF | pythoncom.VT_BSTR, ""), # reply
+            win32com.client.VARIANT(pythoncom.VT_BYREF | pythoncom.VT_BSTR, ""), # error
+            win32com.client.VARIANT(pythoncom.VT_BYREF | pythoncom.VT_I4, 0), # ?
+            win32com.client.VARIANT(pythoncom.VT_BYREF | pythoncom.VT_I4, 0)] # ?
+        err = mvu.SendPpmsCommand(*args)
+        # win32com does invert the order of results!
+        if err == 0:
+            #print '<', args[3].value
+            return args[3].value
+        if err == 1:
+            #print '<done'
+            return "OK"
+        raise Error(args[2].value.replace('\n', ' '))
+
+if __name__ == "__main__": # test only
+    print(QDevice('QD.MULTIVU.PPMS.1').send('LEVEL?'))