#######################
IO-Extension card
#######################
================
Example scenario
================

We have Integral controller with 2 IO-cards in slots 1 and 4.  

Slot 1 io-card contains:

.. table:: 
    :align: left

    +------------------+-------------------+
    | AI-Res           | channels 2 and 4  |
    +------------------+-------------------+
    | AO               | channel 6         |
    +------------------+-------------------+
    | AI-V             | channel 8         |
    +------------------+-------------------+

Slot 4 io-card contains:

.. table:: 
    :align: left

    +------------------+------------------+
    | DO               | channels 2 4 6 8 |
    +------------------+------------------+
    | DI-ext           | channels 10 12   |
    +------------------+------------------+

^^^^^^^^^^^^^
IO-port setup
^^^^^^^^^^^^^

We need to create ioPorts for each card. 

Slot 1:

    pointName: ``ioPorts/rpc/P1``:

        alias: 
            `IOM1`
        device: 
            `/dev/slots/internal/M1_RPC`

Slot 4:

    pointName: ``ioPorts/rpc/P4``:

        alias: 
            `IOM4`
        device: 
            `/dev/slots/internal/M4_RPC`

With this information we can build following dataSources and -targets:  

""
M1
""
sources:

    - `rpc://ioPorts%2Frpc%2FP1/readch/2/2`
    - `rpc://ioPorts%2Frpc%2FP1/readch/4/2`
    - `rpc://ioPorts%2Frpc%2FP1/readch/8/3`

targets:

    - `rpc://ioPorts%2Frpc%2FP1/setch/6/4`

""
M4
""
sources:

    - `rpc://ioPorts%2Frpc%2FP4/readch/10/6`
    - `rpc://ioPorts%2Frpc%2FP4/readch/12/6`

targets:

    - `rpc://ioPorts%2Frpc%2FP4/setch/2/8`
    - `rpc://ioPorts%2Frpc%2FP4/setch/4/8`
    - `rpc://ioPorts%2Frpc%2FP4/setch/6/8`
    - `rpc://ioPorts%2Frpc%2FP4/setch/8/8`

To use the channel as source for point, just add the datasource or datatarget

^^^^^^^^^^^^^^^^^^^^^^^^
datasource/-target logic
^^^^^^^^^^^^^^^^^^^^^^^^  
dataSources and dataTargets (later just also just *dataurls*) use following logic, to read/write to correct place:  
`rpc://device/method/channel/mode`:

    ``device``:
        Pointname of the ioPort  
    ``channel``: 
        is the channel number  
    ``mode``:
        is the mode which is used for the channel  

.. note:: 
    Note: the pointname needs to be URL-encoded.
    In short it means that if the dataurl contains the character `/` needs to be 
    replaced with ``%2F``. Otherwise parsing of the dataurl will not work correctly.

==================   ============================
Channel Mode Name    Value
==================   ============================
CH_MODE_UNINIT       0  
CH_MODE_GND 	     1  
CH_MODE_AI_RES  	 2  
CH_MODE_AI_VOLTAGE   3
CH_MODE_AO_VOLTAGE   4  
CH_MODE_DI  	     5  
CH_MODE_DI_EXT  	 6  
CH_MODE_PULSE   	 7  #Not yet implemented  
CH_MODE_DO  	     8  
CH_MODE_NTC10   	 9  
CH_MODE_PT1000  	 10  
CH_MODE_NI1000  	 11  
CH_MODE_NI1000_LG    12  
==================   ============================


.. note:: 

    The logic differs from magioRTU in few ways:
    Magio io-modules needs different registers for setting the channel mode and for the 
    actual value of the channel, so you need two database points to handle that behavior.
    You also need 2 different IO-profiles: 1 for channel modes and 1 for the actual value.
    With RPC IO-modules, it is possible bundle channel mode and method in one request.