Source code for pymodbus.constants

'''
Constants For Modbus Server/Client
----------------------------------

This is the single location for storing default
values for the servers and clients.
'''
from pymodbus.interfaces import Singleton


[docs]class Defaults(Singleton): ''' A collection of modbus default values .. attribute:: Port The default modbus tcp server port (502) .. attribute:: Retries The default number of times a client should retry the given request before failing (3) .. attribute:: RetryOnEmpty A flag indicating if a transaction should be retried in the case that an empty response is received. This is useful for slow clients that may need more time to process a requst. .. attribute:: Timeout The default amount of time a client should wait for a request to be processed (3 seconds) .. attribute:: Reconnects The default number of times a client should attempt to reconnect before deciding the server is down (0) .. attribute:: TransactionId The starting transaction identifier number (0) .. attribute:: ProtocolId The modbus protocol id. Currently this is set to 0 in all but proprietary implementations. .. attribute:: UnitId The modbus slave addrss. Currently this is set to 0x00 which means this request should be broadcast to all the slave devices (really means that all the devices should respons). .. attribute:: Baudrate The speed at which the data is transmitted over the serial line. This defaults to 19200. .. attribute:: Parity The type of checksum to use to verify data integrity. This can be on of the following:: - (E)ven - 1 0 1 0 | P(0) - (O)dd - 1 0 1 0 | P(1) - (N)one - 1 0 1 0 | no parity This defaults to (N)one. .. attribute:: Bytesize The number of bits in a byte of serial data. This can be one of 5, 6, 7, or 8. This defaults to 8. .. attribute:: Stopbits The number of bits sent after each character in a message to indicate the end of the byte. This defaults to 1. .. attribute:: ZeroMode Indicates if the slave datastore should use indexing at 0 or 1. More about this can be read in section 4.4 of the modbus specification. .. attribute:: IgnoreMissingSlaves In case a request is made to a missing slave, this defines if an error should be returned or simply ignored. This is useful for the case of a serial server emulater where a request to a non-existant slave on a bus will never respond. The client in this case will simply timeout. ''' Port = 502 Retries = 3 RetryOnEmpty = False Timeout = 3 Reconnects = 0 TransactionId = 0 ProtocolId = 0 UnitId = 0x00 Baudrate = 19200 Parity = 'N' Bytesize = 8 Stopbits = 1 ZeroMode = False IgnoreMissingSlaves = False
[docs]class ModbusStatus(Singleton): ''' These represent various status codes in the modbus protocol. .. attribute:: Waiting This indicates that a modbus device is currently waiting for a given request to finish some running task. .. attribute:: Ready This indicates that a modbus device is currently free to perform the next request task. .. attribute:: On This indicates that the given modbus entity is on .. attribute:: Off This indicates that the given modbus entity is off .. attribute:: SlaveOn This indicates that the given modbus slave is running .. attribute:: SlaveOff This indicates that the given modbus slave is not running ''' Waiting = 0xffff Ready = 0x0000 On = 0xff00 Off = 0x0000 SlaveOn = 0xff SlaveOff = 0x00
[docs]class Endian(Singleton): ''' An enumeration representing the various byte endianess. .. attribute:: Auto This indicates that the byte order is chosen by the current native environment. .. attribute:: Big This indicates that the bytes are in little endian format .. attribute:: Little This indicates that the bytes are in big endian format .. note:: I am simply borrowing the format strings from the python struct module for my convenience. ''' Auto = '@' Big = '>' Little = '<'
[docs]class ModbusPlusOperation(Singleton): ''' Represents the type of modbus plus request .. attribute:: GetStatistics Operation requesting that the current modbus plus statistics be returned in the response. .. attribute:: ClearStatistics Operation requesting that the current modbus plus statistics be cleared and not returned in the response. ''' GetStatistics = 0x0003 ClearStatistics = 0x0004
[docs]class DeviceInformation(Singleton): ''' Represents what type of device information to read .. attribute:: Basic This is the basic (required) device information to be returned. This includes VendorName, ProductCode, and MajorMinorRevision code. .. attribute:: Regular In addition to basic data objects, the device provides additional and optinoal identification and description data objects. All of the objects of this category are defined in the standard but their implementation is optional. .. attribute:: Extended In addition to regular data objects, the device provides additional and optional identification and description private data about the physical device itself. All of these data are device dependent. .. attribute:: Specific Request to return a single data object. ''' Basic = 0x01 Regular = 0x02 Extended = 0x03 Specific = 0x04
[docs]class MoreData(Singleton): ''' Represents the more follows condition .. attribute:: Nothing This indiates that no more objects are going to be returned. .. attribute:: KeepReading This indicates that there are more objects to be returned. ''' Nothing = 0x00 KeepReading = 0xFF
#---------------------------------------------------------------------------# # Exported Identifiers #---------------------------------------------------------------------------# __all__ = [ "Defaults", "ModbusStatus", "Endian", "ModbusPlusOperation", "DeviceInformation", "MoreData", ]