def read_modbus_register(self, reg_addr, reg_qty, parse_format, attempt_count=1, attempt_interval=5):
# Create request with network endianness
struct_format = ("!BBHH")
packed_data = struct.pack(struct_format, self.modbus_addr, self.modbus_func, reg_addr, reg_qty)
packed_data_size = struct.calcsize(struct_format)
# Calculate the CRC16 and append to the end
crc = crc16.calcCRC(packed_data)
crc = socket.htons(crc)
struct_format = ("!BBHHH")
packed_data = struct.pack(struct_format, self.modbus_addr, self.modbus_func, reg_addr, reg_qty, crc)
#print "Packed data: " + repr(packed_data)
sent = False
reply = None
while sent==False and attempt_count>0:
attempt_count = attempt_count-1
try:
# Send data
self.sock.sendall(packed_data)
reply = self.get_modbus_response(reg_qty,parse_format)
sent = True
except socket.error:
if (attempt_count>0):
logging.error("Connection closed by Modbus device %s:%s. Retrying in %s seconds..."%(self.type,self.id,attempt_interval))
time.sleep(attempt_interval)
self.connect()
else:
logging.error("Connection closed by Modbus device %s:%s."%(self.type,self.id))
return reply
def modbusReadReg(self, addr, modbus_func, reg_addr, reg_qty):
# Create request with network endianness
struct_format = ("!BBHH")
packed_data = struct.pack(struct_format, addr, modbus_func, reg_addr, reg_qty)
packed_data_size = struct.calcsize(struct_format)
# Calculate the CRC16 and append to the end
crc = crc16.calcCRC(packed_data)
crc = socket.htons(crc)
struct_format = ("!BBHHH")
packed_data = struct.pack(struct_format, addr, modbus_func, reg_addr, reg_qty, crc)
#print "Packed data: " + repr(packed_data)
sent = False
while sent == False:
try:
# Send data
self.sock.sendall(packed_data)
response = self.getResponse(reg_qty)
sent = True
except socket.error:
print ("Modbus Connection was closed by Modbus Server. "
"Retrying in 5 seconds...")
time.sleep(5)
self.connect()
return response
def read_modbus_register(self,
reg_addr,
reg_qty,
parse_format,
attempt_count=1,
attempt_interval=5):
# Create request with network endianness
struct_format = ("!BBHH")
packed_data = struct.pack(struct_format, self.modbus_addr,
self.modbus_func, reg_addr, reg_qty)
packed_data_size = struct.calcsize(struct_format)
# Calculate the CRC16 and append to the end
crc = crc16.calcCRC(packed_data)
crc = socket.htons(crc)
struct_format = ("!BBHHH")
packed_data = struct.pack(struct_format, self.modbus_addr,
self.modbus_func, reg_addr, reg_qty, crc)
#print "Packed data: " + repr(packed_data)
sent = False
reply = None
while sent == False and attempt_count > 0:
attempt_count = attempt_count - 1
try:
# Send data
self.sock.sendall(packed_data)
reply = self.get_modbus_response(reg_qty, parse_format)
sent = True
except socket.error:
if (attempt_count > 0):
logging.error(
"Connection closed by Modbus device %s:%s. Retrying in %s seconds..."
% (self.type, self.id, attempt_interval))
time.sleep(attempt_interval)
self.connect()
else:
logging.error("Connection closed by Modbus device %s:%s." %
(self.type, self.id))
return reply
