cheap_modbus_rtu
Lightweight control of cheap Modbus RTU components using Python
Public Member Functions | Public Attributes | Static Public Attributes | List of all members
cheap_modbus_rtu.cheap_modbus_io.R4DIF08 Class Reference

Control R4DIF08 8-channel digital input modules via RS-485 Modbus RTU. More...

Public Member Functions

def __init__ (self, int slave_id=1, str serial_device_name=None, int baudrate=9600, **kwargs)
 
bool get_input (self, int input_no)
 Return the state of the specified digital input. More...
 
tuple[bool,...] get_inputs (self)
 Returns the state of the 8 digital inputs. More...
 
def set_input_level (self, active_high=False, delay_enabled=True)
 Set input inverters, or voltage level for boolean True output. More...
 
int get_slave_id (self)
 Sends a broadcast query to all devices on the bus. More...
 
def set_slave_id (self, int slave_id_new)
 Set the slave ID. More...
 
def set_baudrate (self, int baudrate=9600)
 Set RS485 serial baud rate. More...
 
def do_factory_reset (self)
 Restore factory default settings. More...
 

Public Attributes

 master
 
 slave_id
 

Static Public Attributes

int INPUT_REG_OFFSET = 40129
 
int INPUT_CONF_REGISTER = 40253
 
int SLAVE_ID_REGISTER = 40255
 
int BAUDRATE_REGISTER = 40256
 
int FACTORY_RESET_REGISTER = 40256
 
int FACTORY_RESET_VALUE = 5
 
int BROADCAST_SLAVE_ID = 0xFF
 
dictionary BAUDRATE_KEYS = {1200: 0, 2400: 1, 4800: 2, 9600: 3, 19200: 4}
 

Detailed Description

Control R4DIF08 8-channel digital input modules via RS-485 Modbus RTU.

The R4DIF08 seem to come with a pre-set slave ID of 1.

Brand name is "eletechsup", available at https://www.eletechsup.com

This is for the three-channel variant.

Member Function Documentation

◆ do_factory_reset()

def cheap_modbus_rtu.cheap_modbus_io.ModbusModuleABC.do_factory_reset (   self)
inherited

Restore factory default settings.

   You must cycle the power supply after this command.

   Expect a CRC mismatch error when invoking this function,
   I don't know if this is always the case.

Reimplemented in cheap_modbus_rtu.cheap_modbus_io.RelayModule.

◆ get_input()

bool cheap_modbus_rtu.cheap_modbus_io.R4DIF08.get_input (   self,
int  input_no 
)

Return the state of the specified digital input.

Parameters
input_noInput number, starts counting at 1
Returns
True if input signal is active, False if inactive

◆ get_inputs()

tuple[bool, ...] cheap_modbus_rtu.cheap_modbus_io.R4DIF08.get_inputs (   self)

Returns the state of the 8 digital inputs.

Returns
Tuple of 8 boolean flags, one for each input

◆ get_slave_id()

int cheap_modbus_rtu.cheap_modbus_io.ModbusModuleABC.get_slave_id (   self)
inherited

Sends a broadcast query to all devices on the bus.

   This only works when only one device is attached to the bus
Returns
The first found slave ID.

◆ set_baudrate()

def cheap_modbus_rtu.cheap_modbus_io.ModbusModuleABC.set_baudrate (   self,
int   baudrate = 9600 
)
inherited

Set RS485 serial baud rate.

   Most devices require cycling the power supply after running this command
   before the new baud rate applies.
Warning
While usually undocumented, it is possible that the device writes directly to FLASH, thus frequent writes could damage the chip!
Parameters
baudrateCan be 1200, 2400, 4800, 9600 (default) or 19200

Reimplemented in cheap_modbus_rtu.cheap_modbus_io.RelayModule.

◆ set_input_level()

def cheap_modbus_rtu.cheap_modbus_io.R4DIF08.set_input_level (   self,
  active_high = False,
  delay_enabled = True 
)

Set input inverters, or voltage level for boolean True output.

   The module only supports setting all inputs at once, so this
   applies to all eight inputs.

   There seems to be a delay necessary in order for the module to be
   re-configured and ready to answer queries after setting this register.

   This is why a 0.2 second blocking delay is activated by default.
Warning
While undocumented, it is possible that the device writes directly to FLASH, thus frequent writes could damage the chip!
Parameters
active_highIf set to False (default), Report True for low-level input (0 V, GND). If set to True, Report True for high-level input (> VCC/2).
delay_enabledEnable 0.2 second delay if set to True (default)

◆ set_slave_id()

def cheap_modbus_rtu.cheap_modbus_io.ModbusModuleABC.set_slave_id (   self,
int  slave_id_new 
)
inherited

Set the slave ID.

Warning
While usually undocumented, it is possible that the device writes directly to FLASH, thus frequent writes could damage the chip!
Parameters
slave_id_newNew Modbus slave ID

Reimplemented in cheap_modbus_rtu.cheap_modbus_io.RelayModule.


The documentation for this class was generated from the following file: