eth-bridge-pru-serial485

Ethernet bridge for Beaglebone's PRUserial485 module

This python module was developed to run PRUserial485 commands remotely in a Beaglebone Black from any other workstation, based on TCP/IP socket connections.

• Port 5000: for write/read commands, operations directly using serial RS485, which depends on the equipment response or serial line availability (blocking functions).
• Port 6000: for general commands, which only depends on BBB memory access and answer is always immediate.
• Port 5500: daemon socket. Use: TBD.

To find out whether ports 5000 and 6000 are available for connecting, you may use wait-for-it.

Server side - Beaglebone Black

Server side contents are available in folder server, which will be necessary to build the bridge to the BBB that will effectively run PRUserial485 commands.

Simple configuration: PRUserial485 library for BeagleboneBlack is needed (find it at pru-serial485 repo).

For building it, enter the folder server and run make install. This will copy service file into BBB system.

Server service is not launched automatically every BBB booting. Once all BBB pins are configured correctly, start it:

systemctl start eth-bridge-pru-serial485.service

Client side - another computer

Client side contents are in folder client, and will be needed on host computer, which will be linked to a Beaglebone Black.

In order to have this module on your system, enter the project folder and install it:

• cd client/
• python-sirius -m pip install . or
• sudo python-sirius setup.py install

Using the Python module

In your Python code, you can just:

import PRUserial485

It is not needed to copy any library files to your project. Package siriuspy is needed to get the server IP on the beaglebone

Before use, the Beaglebone IP must be defined on declaration

PRUserial485.EthBridgeClient("10.11.11.11")

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Available Methods

Identical to pru-serial485 methods.

General Purpose

• PRUserial485_open(int baudrate, char mode)

  PRU initialization. Shared memory configuration and loading binaries into PRU.

  • baudrate:
    RS485 serial desired baudrate. Available: 9600, 14400, 19200, 38400, 57600, 115200 bps and 6, 10, 12 Mbps
  • mode:
    "M" for master and "S" for slave mode.

• PRUserial485_address()

  Gets SERIALxxCON board address (hardware defined) Returns: integer value (0 to 31)

• PRUserial485_close()

  Closes PRUs and memory mapping.

• PRUserial485_write(char_list data, float timeout)

  Sending data through RS485 network

  Parameters

  • data:
    Python char list containing values to be transmitted through serial network.
  • timeout:
    Maximum waiting time to start getting an answer, in milliseconds (ms). Minimum: 15ns / Maximum: 64s. If 0, does not wait for response. ATTENTION: in slave mode, this parameter is ignored.

  Return

  • MASTER MODE:
    Returns only after response received (valid response, timeout or ignored)
  • SLAVE MODE:
    Returns just after data completely sent.

• PRUserial485_read()

  Receiving data through RS485 network

  Return: List of characters corresponding to data received.

Curves

• PRUserial485_curve(float_list curve1, float_list curve2, float_list curve3, float_list curve4, int block)

  Storing curves into memory. Each curve correspond to a power supply in the crate.

  Parameters

  • curveX:
    Python float list containing curve points, up to 6250 points. Curves must all have same length.
  • block:
    Identification of block which will be loaded with curve points. (0 to 3)

• PRUserial485_set_curve_block(int block)

  Selection of block which will be performed in next cycle. Default value is 0.

  Parameters

  • block:
    Identification of block (0 to 3)

• PRUserial485_read_curve_block()

  Read block identification which will be performed in next cycle.

  Returns: Block indentification (0 to 3)

• PRUserial485_set_curve_pointer(int next_point)

  Selection of point of curve that will be performed after the next sync pulse

  Parameters

  • next_point:
    index of next point (0 to (len(curve)-1))

• PRUserial485_read_curve_pointer()

  Read curve index (point) which will be sent in next sync pulse.

  Returns: index of next point (0 to (len(curve)-1))

Sync Operation

• PRUserial485_sync_start(int sync_mode, float delay, int sync_address)

  Sync mode operation.

  Parameters

  • sync_mode:
    | 0x51 - Single curve sequence & Intercalated read messages
    | 0x5E - Single curve sequence & Read messages at End of curve
    | 0xC1 - Continuous curve sequence & Intercalated read messages
    | 0xCE - Continuous curve sequence & Read messages at End of curve
    | 0x5B - Single Sequence - Single Broadcast Function command
  • delay:
    time between end of sync serial message and start of a normal message, when sending normal commands after sync pulses.
  • sync_address:
    PS Controller address to which setpoints will be addressed to. Parameter only needed if sync_mode != 0x5B

• PRUserial485_sync_stop()

  Stops sync operation mode.

• PRUserial485_sync_status()

  Verifies whether PRU is waiting for a sync pulse or not

  Returns: boolean True or False

• PRUserial485_read_pulse_count_sync()

  Read number of sync pulses already received.

  Returns: counting value (0 to (2^32 - 1))

• PRUserial485_clear_pulse_count_sync()

  Clears pulse counting registers. Action is only performed if sync mode is disabled.

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