def get_pv_value(self, name, to_string=False, timeout=TIMEOUT):
"""Get the current value of the PV"""
name = MYPVPREFIX + ':' + name
if name not in CACHE.keys():
chan = CaChannel(name)
chan.setTimeout(TIMEOUT)
#Try to connect - throws if cannot
chan.searchw()
CACHE[name] = chan
else:
chan = CACHE[name]
ftype = chan.field_type()
if ca.dbr_type_is_ENUM(ftype) or ca.dbr_type_is_CHAR(
ftype) or ca.dbr_type_is_STRING(ftype):
to_string = True
if to_string:
if ca.dbr_type_is_ENUM(ftype):
value = chan.getw(ca.DBR_STRING)
else:
value = chan.getw(ca.DBR_CHAR)
#Could see if the element count is > 1 instead
if isinstance(value, list):
return self._waveform2string(value)
else:
return str(value)
else:
return chan.getw()
def set_pv_value(self, name, value, wait=False, timeout=TIMEOUT):
"""Set the PV to a value.
When getting a PV value this call should be used, unless there is a special requirement.
Parameters:
name - the PV name
value - the value to set
wait - wait for the value to be set before returning
"""
name = MYPVPREFIX + ':' + name
if name not in CACHE.keys():
chan = CaChannel(name)
chan.setTimeout(TIMEOUT)
#Try to connect - throws if cannot
chan.searchw()
CACHE[name] = chan
else:
chan = CACHE[name]
if wait:
chan.putw(value)
else:
def putCB(epics_args, user_args):
#Do nothing in the callback
pass
ftype = chan.field_type()
ecount = chan.element_count()
chan.array_put_callback(value, ftype, ecount, putCB)
chan.flush_io()
for record in db.values():
if rtyps and record.rtyp not in rtyps:
continue
# issue connect requests and wait for connection
chans = {}
for field in record.fields:
chan = CaChannel(record.name + '.' + field)
chan.search()
chans[field] = chan
ca.pend_io(10)
# issue read requests and wait for completion
for chan in chans.values():
chan.array_get(ca.dbf_type_to_DBR_CTRL(chan.field_type()))
ca.pend_io(10)
# compare and print
all_consistent = True
for field, chan in chans.items():
# get configured value
config_value = record.fields[field]
# skip those with empty config values
if config_value == '':
continue
# dbr is a dict containing the channel information
dbr = chan.getValue()
actual_value = dbr['pv_value']
class pv():
# Wrapper for associating CaChannel class to specific PV using its name
def __init__(self, pvname):
try:
self.pv = CaChannel()
self.pv.searchw(pvname)
self.alarm_status = "n/a" # used to store severity provided by callback
self.alarm_severity = "n/a" # used to store severity provided by callback
except :
raise Exception("****** PV not found - "+pvname+" ******")
#return pv
# Wrapper for putw() function - writing a value to PV and waiting for input records to scan (update their value)
def write(self, *args):
try:
if len(args) == 2: # arguments: value, scan_time
self.pv.putw(args[0])
time.sleep(args[1])
if len(args) == 3: # arguments: value, scan_time, type
if args[2] == "STRING":
self.pv.putw(args[0],ca.DBR_STRING)
else:
raise Exception("Type "+ str(args[3]) +" not recognized")
time.sleep(args[1])
print("***W: Set PV "+self.pv.name()+" to "+str(args[0]))
except:
print("Could not set PV "+self.pv.name()+" to "+str(args[0]))
# Similar to write() except it does not print output when successfully sets the value
# Useful for setUp and tearDown methods
def write_silent(self, *args):
try:
if len(args) == 2: # arguments: value, scan_time
self.pv.putw(args[0])
time.sleep(args[1])
if len(args) == 3: # arguments: value, scan_time, type
if args[2] == "STRING":
self.pv.putw(args[0],ca.DBR_STRING)
else:
raise Exception("Type "+ str(args[3]) +" not recognized")
time.sleep(args[1])
except:
print("Could not set PV "+self.pv.name()+" to "+str(args[0]))
# Wrapper for getw()
def read(self, *args):
if len(args) == 1:
if args[0] == "STRING":
val = self.pv.getw(ca.DBR_STRING)
else:
raise Exception("Type "+ str(args[3]) +" not recognized")
print("***R: Read PV "+self.pv.name()+" value "+str(val))
return val
else:
val = self.pv.getw()
print("***R: Read PV "+self.pv.name()+" value "+str(val))
return val
# Wrapper for getw() with CALLBACK for alarm status/severity
def read_alarm(self):
self.pv.array_get_callback(ca.dbf_type_to_DBR_STS(self.pv.field_type()), None, Callback, self)
self.pv.flush_io()
for i in range(20):
self.pv.pend_event()
# Wrapper for name()
def name(self):
return self.pv.name()
