87 lines
2.5 KiB
Python
87 lines
2.5 KiB
Python
from pymodbus.client.sync import ModbusSerialClient
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from pymodbus.pdu import ExceptionResponse
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import RS485Ext
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import struct
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import time
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def registersToIeeeFloat(i):
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return struct.unpack('f', bytes(
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[((x & 0xff00) >> 8) if y else (x & 0x00ff)
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for x in i[::-1]
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for y in [False, True]
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]
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)
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)[0]
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def registersToIeeeFloatReverse(i):
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return struct.unpack('f', bytes(
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[((x & 0xff00) >> 8) if y else (x & 0x00ff)
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for x in i
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for y in [False, True]
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]
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)
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)[0]
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def dataConverter(t, d):
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if t == 'F':
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return registersToIeeeFloat(d)
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elif t == 'RF':
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return registersToIeeeFloatReverse(d)
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else:
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raise Exception("Converter '{0}' is not supported".format(t))
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class ModbusException(Exception):
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def __init__(self, resp):
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self.msg = str(result)
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def __str__(self):
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return self.msg
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class ModbusRequestDefinition(object):
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def __init__(self, unit, address, count, converter, label):
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self.unit = unit
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self.address = address
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self.count = count
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self.converter = converter
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self.label = label
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reqs = [
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ModbusRequestDefinition(1, 0x2000, 2, 'F', 'Voltage'),
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ModbusRequestDefinition(1, 0x2020, 2, 'F', 'Frequency'),
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ModbusRequestDefinition(1, 0x2060, 2, 'F', 'Current'),
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ModbusRequestDefinition(3, 0x0004, 2, 'RF', 'Resistance Channel 1'),
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ModbusRequestDefinition(3, 0x000C, 2, 'RF', 'Temperature Channel 1'),
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ModbusRequestDefinition(3, 0x0014, 2, 'RF', 'Resistance Channel 2'),
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ModbusRequestDefinition(3, 0x001C, 2, 'RF', 'Temperature Channel 2'),
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]
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ser=RS485Ext.RS485Ext(port='/dev/ttyAMA0', baudrate=1200, stopbits=1,
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timeout=1)
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client = ModbusSerialClient(method='rtu')
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client.socket = ser
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client.connect()
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delay = 0.05
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while True:
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for req in reqs:
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try:
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time.sleep(delay)
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result = client.read_holding_registers(req.address, req.count, req.unit)
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if type(result) in (ExceptionResponse):
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raise ModbusException(result)
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print("{0}: {1:.2f}". format(dataConverter(req.converter, result.registers)))
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except ModbusException as e:
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print("ERROR: %s" % e)
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finally:
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print("-------------")
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time.sleep(10)
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client.close()
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