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Temperature Min and Max Control #12

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Temperature Min and Max Control #12

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85 changes: 46 additions & 39 deletions watlow/driver.py
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Original file line number Diff line number Diff line change
Expand Up @@ -52,17 +52,24 @@ class TemperatureController(object):
* Second checksum is a custom CRC-16 following Bacnet spec.
"""

commands = {'actual': unhexlify('55ff0510000006e8010301040101e399'),
'setpoint': unhexlify('55ff0510000006e80103010701018776'),
'set': {'header': unhexlify('55ff051000000aec'),
'body': unhexlify('010407010108')}}
commands = {
"actual": unhexlify("55ff0510000006e8010301040101e399"),
"setpoint": unhexlify("55ff0510000006e80103010701018776"),
"set": {
"header": unhexlify("55ff051000000aec"),
"body": unhexlify("010407010108"),
},
}
responses = {
'actual': re.compile('^55ff060010000b8802030104010108'
'([0-9a-f]{8})([0-9a-f]{4})$'),
'setpoint': re.compile('^55ff060010000b8802030107010108'
'([0-9a-f]{8})([0-9a-f]{4})$'),
'set': re.compile('^55ff060010000a76020407010108'
'([0-9a-f]{8})([0-9a-f]{4})$')
"actual": re.compile(
"^55ff060010000b8802030104010108" "([0-9a-f]{8})([0-9a-f]{4})$"
),
"setpoint": re.compile(
"^55ff060010000b8802030107010108" "([0-9a-f]{8})([0-9a-f]{4})$"
),
"set": re.compile(
"^55ff060010000a76020407010108" "([0-9a-f]{8})([0-9a-f]{4})$"
),
}

def __init__(self, port, timeout=0.5):
Expand All @@ -75,15 +82,13 @@ def __init__(self, port, timeout=0.5):
self.baudrate = 38400
self.timeout = timeout
self.connection = None
self.min_temp = -65
self.max_temp = 200
self.open()

def open(self):
"""Open up a serial connection to the oven."""
self.connection = serial.Serial(
self.port,
self.baudrate,
timeout=self.timeout
)
self.connection = serial.Serial(self.port, self.baudrate, timeout=self.timeout)

def close(self):
"""Close the serial connection. Use on cleanup."""
Expand All @@ -92,27 +97,27 @@ def close(self):

def get(self):
"""Get the current temperature and setpoint, in C."""
output = {'actual': None, 'setpoint': None}
output = {"actual": None, "setpoint": None}
for key in output:
output[key] = self._write_and_read(
request=self.commands[key],
length=21,
check=self.responses[key]
request=self.commands[key], length=21, check=self.responses[key]
)
return output

def set(self, setpoint):
"""Set the setpoint temperature, in C."""
body = self.commands['set']['body'] + struct.pack('>f', c_to_f(setpoint))
checksum = struct.pack('<H', ~crc(body) & 0xffff)
body = self.commands["set"]["body"] + struct.pack(">f", c_to_f(setpoint))
checksum = struct.pack("<H", ~crc(body) & 0xFFFF)
response = self._write_and_read(
request=self.commands['set']['header'] + body + checksum,
request=self.commands["set"]["header"] + body + checksum,
length=20,
check=self.responses['set']
check=self.responses["set"],
)
if round(setpoint, 2) != round(response, 2):
raise IOError(f"Could not change setpoint from "
f"{response:.2f}°C to {setpoint:.2f}°C.")
raise IOError(
f"Could not change setpoint from "
f"{response:.2f}°C to {setpoint:.2f}°C."
)

def _write_and_read(self, request, length, check, retries=3):
"""Write to and read from the device.
Expand All @@ -136,15 +141,15 @@ def _write_and_read(self, request, length, check, retries=3):
self.connection.write(request)
response = self.connection.read(length)
except serial.serialutil.SerialException:
return self._write_and_read(request, length, check, retries-1)
return self._write_and_read(request, length, check, retries - 1)
match = check.match(bytes.hex(response))
if not match:
return self._write_and_read(request, length, check, retries-1)
return self._write_and_read(request, length, check, retries - 1)
value = match.group(1)
# From docstring, `checksum = match.group(2)` could be added and checked.
temperature = f_to_c(struct.unpack('>f', unhexlify(value))[0])
if temperature < 0 or temperature > 250:
return self._write_and_read(request, length, check, retries-1)
temperature = f_to_c(struct.unpack(">f", unhexlify(value))[0])
if temperature < self.min_temp or temperature > max_temp:
return self._write_and_read(request, length, check, retries - 1)
return temperature


Expand All @@ -166,17 +171,16 @@ async def get(self, zone: int):
For more information on a 'Zone', refer to Watlow manuals.
"""
output = {
'actual': self.actual_temp_address,
'setpoint': self.setpoint_address,
'output': self.output_address,
"actual": self.actual_temp_address,
"setpoint": self.setpoint_address,
"output": self.output_address,
}
for k, v in output.items():
address = (zone - 1) * self.modbus_offset + v
try:
result = await self.read_registers(address, 2)
output[k] = BinaryPayloadDecoder.fromRegisters(
result,
byteorder=Endian.Big
result, byteorder=Endian.Big
).decode_32bit_float()
except AttributeError:
output[k] = None
Expand All @@ -188,10 +192,13 @@ async def set_setpoint(self, zone: int, setpoint: float):
For more information on a 'Zone', refer to Watlow manuals.
"""
if not self.setpoint_range[0] <= setpoint <= self.setpoint_range[1]:
raise ValueError(f"Setpoint ({setpoint}) in not in the valid range from"
f" {self.setpoint_range[0]} to {self.setpoint_range[1]}")
raise ValueError(
f"Setpoint ({setpoint}) in not in the valid range from"
f" {self.setpoint_range[0]} to {self.setpoint_range[1]}"
)
address = (zone - 1) * self.modbus_offset + self.setpoint_address
builder = BinaryPayloadBuilder(byteorder=Endian.Big)
builder.add_32bit_float(setpoint)
await self.client.protocol.write_registers(address, builder.build(),
skip_encode=True)
await self.client.protocol.write_registers(
address, builder.build(), skip_encode=True
)