Sum commands: many reads, writes, or read-writes in one ADS read-write, to an index group of the system services with the number of them as index offset.
| Index group | Write data | Read data |
|---|---|---|
0xF080, reads | each {index_group, index_offset, length} | the return codes, then the data of each |
0xF081, writes | each {index_group, index_offset, length}, then the data of each | the return codes |
0xF082, read-writes | each {index_group, index_offset, read_length, write_length}, then the data written | each return code and length read, then the data read |
Each part of the request and of the response is the same 32-bit little-endian numbers as the
single commands'. Beckhoff recommends at most 500 at a time (max/0): a device does them all
before its next cycle.
The results come in the order asked, each {:ok, data} or :ok, or {:error, name} with its
return code:
iex> reads = [{0x4020, 0, 2}, {0x4020, 8, 1}]
iex> {:read_write, 0xF080, 2, 11, _headers} = ADS.Sum.read(reads)
iex> ADS.Sum.decode_read(reads, <<0::32, 0x703::32-little, 7, 0, 0>>)
{:ok, [{:ok, <<7, 0>>}, {:error, :device_invalid_offset}]}Summary
Functions
The results of sum reads, from the data of the response. A device gives the data of each read in full, but one that gives none for those that failed is understood too.
The results of sum read-writes, from the data of the response.
The results of sum writes, from the data of the response.
The most sub-commands Beckhoff recommends in one sum command: 500.
A request of sum reads, each {index_group, index_offset, length}.
A request of sum read-writes, each {index_group, index_offset, read_length, data}, as for
getting many handles at once.
A request of sum writes, each {index_group, index_offset, data}.
Functions
@spec decode_read( [{ADS.index_group(), ADS.index_offset(), non_neg_integer()}], binary() ) :: {:ok, ok: binary(), error: ADS.error()} | {:error, {:invalid_response, binary()}}
The results of sum reads, from the data of the response. A device gives the data of each read in full, but one that gives none for those that failed is understood too.
@spec decode_read_write([term()], binary()) :: {:ok, ok: binary(), error: ADS.error()} | {:error, {:invalid_response, binary()}}
The results of sum read-writes, from the data of the response.
@spec decode_write([term()], binary()) :: {:ok, [:ok | {:error, ADS.error()}]} | {:error, {:invalid_response, binary()}}
The results of sum writes, from the data of the response.
@spec max() :: 500
The most sub-commands Beckhoff recommends in one sum command: 500.
@spec read([{ADS.index_group(), ADS.index_offset(), non_neg_integer()}]) :: ADS.Command.request()
A request of sum reads, each {index_group, index_offset, length}.
@spec read_write([ {ADS.index_group(), ADS.index_offset(), non_neg_integer(), binary()} ]) :: ADS.Command.request()
A request of sum read-writes, each {index_group, index_offset, read_length, data}, as for
getting many handles at once.
@spec write([{ADS.index_group(), ADS.index_offset(), binary()}]) :: ADS.Command.request()
A request of sum writes, each {index_group, index_offset, data}.