M-Bus

api.mbusTransaction(msg, timeout, retry)

Overview

Transmit "msg" and wait given "timeout" milliseconds for the answer. The transmission is retried "retry" times.

Turn on MBus using mbusState first.

Arguments

• msg (string) - Message sent to MBus
• timeout (integer) - The maximum time in milliseconds to wait for answer from MBus device
• retry (integer) - Optional number of retransmissions, default number is 1

Return

• status (integer) - Number of bytes received, zero on failure
• c (integer) - MBus c frame field
• a (integer) - MBus a frame field
• ci (integer) - MBus ci frame field
• answer (string) - MBus frame payload received from the bus

Example

--Send MBus frame [0x10, 0x50, 0x30, 0x16] and wait 5s for the answer twice
msg = pack.pack('<b4', 0x10, 0x50, 0x30, 0x16)
status,c,a,ci,ans = api.mbusTransaction(msg, 5000, 2)

api.mbusSetup(baudrate, parity, stopBits, dataBits)

Overview

Configures the MBus communication interface. Configuration from GUI is used by default, but it can be overriden using this function.

Turn on M-Bus using mbusState after setting up M-Bus parameters using this function.

Arguments

• baudrate (integer) - Baudrate to use for communication (up to 921600 baud)
• parity (integer) - Parity, 0 for none, 1 for odd and 2 for even parity
• stopBits (integer) - Number of stop bits, 1 or 2 allowed
• dataBits (integer) - Number of data bits, 7 or 8 allowed

Example

--setup M-Bus interface to 9600 Baud, 8E2
api.mbusSetup(9600, 2, 2, 8)

api.mbusState(state)

Overview

Turns on the M-Bus circuitry.

Must be used before function api.mbusTransaction().

Arguments

• state (integer) - New state of MBus circuitry: 0 for off, 1 for on (apprx 30s power-up)

Example

api.mbusState(1) --turn on M-Bus