The AL state machine of a SubDevice (ETG.1000.6, 6.4.1), through its AL control and AL status registers (5.3).
| State | Code | The SubDevice |
|---|---|---|
:init | 1 | is set up by the MainDevice, its mailbox sync managers among the rest |
:pre_operational | 2 | has its mailbox working, and no process data |
:bootstrap | 3 | takes firmware over FoE, and nothing else |
:safe_operational | 4 | gives its inputs, and holds its outputs in their safe state |
:operational | 8 | gives its inputs and drives its outputs |
From Init there is a way to Pre-Operational and Bootstrap only, and from Pre-Operational none straight to Operational; any state can go down to one below it. A change that fails leaves the SubDevice with its error flag set and an AL status code that says why, until the MainDevice acknowledges it.
Summary
Functions
The code of a state in AL control and AL status.
AL status from its six bytes, from 0x0130: the state, the error flag, whether R6 holds a device identification, and the AL status code, which counts only with the error flag set.
What an AL status code means, in a few words.
Reads a SubDevice's AL status, by station address.
Asks a SubDevice for a state, by station address, and waits until it is there: :ok, or
{:error, {:al_status, state, code}} with the state it is in and the AL status code it gave for
refusing, or {:error, :timeout}. A refusal is acknowledged, as is an error from before, so that
the SubDevice can be asked again.
The state of a code, or the code itself for one the spec doesn't define.
Every state, from Init up.
Types
Functions
The code of a state in AL control and AL status.
AL status from its six bytes, from 0x0130: the state, the error flag, whether R6 holds a device identification, and the AL status code, which counts only with the error flag set.
iex> EtherCAT.AL.decode_status(<<0x14, 0, 0, 0, 0x1E, 0>>)
%{state: :safe_operational, error: true, id_loaded: false, code: 0x001E}@spec describe(0..65535) :: String.t()
What an AL status code means, in a few words.
iex> EtherCAT.AL.describe(0x001E)
"The inputs are set up wrong"
iex> EtherCAT.AL.describe(0x8001)
"Vendor specific (0x8001)"@spec read_status(EtherCAT.MainDevice.t(), 0..65535) :: {:ok, status()} | {:error, term()}
Reads a SubDevice's AL status, by station address.
@spec request(EtherCAT.MainDevice.t(), 0..65535, state(), keyword()) :: :ok | {:error, {:al_status, state() | byte(), 0..65535} | :timeout | term()}
Asks a SubDevice for a state, by station address, and waits until it is there: :ok, or
{:error, {:al_status, state, code}} with the state it is in and the AL status code it gave for
refusing, or {:error, :timeout}. A refusal is acknowledged, as is an error from before, so that
the SubDevice can be asked again.
Options:
timeout:(5 seconds), how long it may take
The state of a code, or the code itself for one the spec doesn't define.
@spec states() :: [state()]
Every state, from Init up.