def PV(self, attr, connect=True, **kw):
"""return epics.PV for a device attribute"""
if attr in self._aliases:
attr = self._aliases[attr]
if attr not in self._pvs and attr not in no_attrs:
pvname = attr
if self._prefix is not None:
pvname = "%s%s" % (self._prefix, attr)
self._pvs[attr] = get_pv(pvname, **kw)
if connect and not self._pvs[attr].connected:
self._pvs[attr].wait_for_connection()
return self._pvs[attr]
def restore_pvs(filepath, debug=False):
"""
Restore pvs from a save file via Channel Access
debug - Set to True if you want a line printed for each value set
Returns True if all pvs were restored successfully.
"""
pv_vals = []
failures = []
# preload PV names and values, hoping PV connections happen in background
with open(filepath, 'r') as fh:
for line in fh.readlines():
if len(line) < 2 or line.startswith('<END') or line.startswith(
'#'):
continue
pvname, value = [w.strip() for w in line[:-1].split(' ', 1)]
if value.startswith('@array@'):
value = value.replace('@array@', '').strip()
if value.startswith('{') and value.endswith('}'):
value = value[1:-1]
value = json.loads(value)
thispv = get_pv(pvname, connect=False)
pv_vals.append((thispv, value))
for thispv, value in pv_vals:
thispv.connect()
pvname = thispv.pvname
if not thispv.connected:
print("Cannot connect to %s" % (pvname))
elif not thispv.write_access:
print("No write access to %s" % (pvname))
else:
if debug:
print("Setting %s to %s" % (pvname, value))
try:
thispv.put(value, wait=False)
except:
exctype, excvalue, exctrace = sys.exc_info()
print("Error restoring %s to %s : %s" %
(pvname, value, exctype, excvalue))
failues.append(pvname)
return len(failures) == 0
def add_pv(self, pvname, attr=None, **kw):
"""add a PV with an optional attribute name that may not exactly
correspond to the mapping of Attribute -> Prefix + Delim + Attribute
That is, with a device defined as
>>> dev = Device('XXX', delim='.')
getting the VAL attribute
>>> dev.get('VAL') # or dev.VAL
becomes 'caget(XXX.VAL)'. With add_pv(), one can add a
non-conforming PV to the collection:
>>> dev.add_pv('XXX_status.VAL', attr='status')
and then use as
>>> dev.get('status') # or dev.status
If attr is not specified, the full pvname will be used.
"""
if attr is None:
attr = pvname
self._pvs[attr] = get_pv(pvname, **kw)
return self._pvs[attr]
def read_request_file(self, request_file=None):
if request_file is not None:
self.request_file = request_file
self.pvs = []
for pvname in _parse_request_file(request_file):
self.pvs.append(get_pv(pvname, connect=False))