#!/usr/bin/env python3
import caproto
from caproto.server import PVGroup, ioc_arg_parser, pvproperty, run
[docs]class RecordMockingIOC(PVGroup):
# Define three records, an analog input (ai) record:
A = pvproperty(value=1.0, record='ai')
# And an analog output (ao) record:
B = pvproperty(value=2.0, record='ao',
precision=3)
# and an ai with all the bells and whistles
C = pvproperty(value=0.0,
record='ai',
upper_alarm_limit=2.0,
lower_alarm_limit=-2.0,
upper_warning_limit=1.0,
lower_warning_limit=-1.0,
upper_ctrl_limit=3.0,
lower_ctrl_limit=-3.0,
units="mm",
precision=3,
doc='The C pvproperty')
@B.putter
async def B(self, instance, value):
if value == 1:
# Mocked record will pick up the alarm status simply by us raising
# an exception in the putter:
raise ValueError('Invalid value!')
# It's also possible to modify some of the behavior of fields on a per-
# record basis. The following function is called whenever A.RVAL is put to:
@A.fields.current_raw_value.putter
async def A(fields, instance, value):
# However, somewhat confusingly, 'self' in this case is the fields
# associated with 'A'. To access the IOC (i.e., the main PV group)
# use the following:
ioc = fields.parent.group
print(f'A.RVAL: Writing values to A and B: {value}')
await ioc.B.write(value)
await ioc.A.write(value)
# Similarly, you can refer to the fields by their usual PV name:
@B.fields.RVAL.putter
async def B(fields, instance, value):
ioc = fields.parent.group
print('B.RVAL: Writing modified values to A, B')
await ioc.B.write(value + 10)
await ioc.A.write(value - 10)
# Now that the field specification has been set on B, it can be reused:
D = pvproperty(value=2.0,
precision=3,
field_spec=B.field_spec)
# D will also be reported as an 'ao' record like B, as it uses the same
# field specification.
E = pvproperty(value='this is a test',
record='stringin',
dtype=caproto.ChannelType.STRING,
)
if __name__ == '__main__':
ioc_options, run_options = ioc_arg_parser(
default_prefix='mock:',
desc='Run an IOC that mocks an ai (analog input) record.')
# Instantiate the IOC, assigning a prefix for the PV names.
ioc = RecordMockingIOC(**ioc_options)
print('PVs:', list(ioc.pvdb))
# ... but what you don't see are all of the analog input record fields
print('Fields of B:', list(ioc.B.fields.keys()))
print('Custom field specifications of A:', RecordMockingIOC.A.fields)
print('Custom field specifications of B:', RecordMockingIOC.B.fields)
print('Custom field specifications of C:', RecordMockingIOC.C.fields)
print('Custom field specifications of D:', RecordMockingIOC.D.fields)
print('Custom field specifications of E:', RecordMockingIOC.E.fields)
# Run IOC.
run(ioc.pvdb, **run_options)