Communication driver

Models the communication with the gateway in order to connect to different software.

Mandatory children

• type: The type of driver. Each driver has its required setup data.
  • Var: smtk_comm_driver_choice
  • Type: constant
  • Possible values: acs_spiiplus | allenbradley_logix | abb_driver | cprog_cri | development | enip_generic_device | fanuc_roboguide | hokuyo_uam | kuka_varproxy | micro800_http | modbustcp_master | mqtt_client | omron_fins | omron_nexsocket | opcda_client | opcua_client | plcsim | plcsim_advanced | robodk_driver | rosbridge | s7protocol | simit | simulink_udp | sqlite3_conn | twincat_ads | udp_driver | ur_driver | yaskawa_plci
  • Default value: opcua_client
• enable: Enable or disable the driver.
  • Var: smtk_bool
  • Doc: (bool)
  • Type: input
  • Default value: false
• setup_data: Setup for the driver in JSON (more info below).
  • Var: smtk_string
  • Type: input
  • Default value: {}
• update_input: Update the inputs to the driver from the system in JSON. It contains the variables names as keys and their values.
  • Var: smtk_string
  • Type: input
  • Default value: {}
• update_output: Update the outputs from the driver to the system in JSON. It contains the variables names as keys and their values.
  • Var: smtk_string
  • Type: output
  • Default value: {}
• status: The status of the driver (connecting, connected, standby, running, error).
  • Var: smtk_string
  • Type: output
  • Default value: none
• info: Debug messages from the driver.
  • Var: smtk_string
  • Type: output
  • Default value: none

Setup data

The setup data is a JSON string that must contain two mandatory items:

Parameters

These values exposes the configuration or context used by the drivers to connect to other platforms. All the drivers share three common parameters (rpi, force_write and auto_reset). Except for these, each driver has its own specific parameters, which can be found on their pages here in the user manual.

The parameters are defined by a dict that may include several items following the next format {parameter_name: parameter_value}, i.e:

{
  "rpi": 35,
  "force_write": 0.5,
  "auto_reset": 5.0
}

Common parameters

• rpi: How often vars are read and write in ms. Default: 50
• force_write: Used to periodically (in s) re-write variables. Default: 1.0
• auto_reset: Used to define the time (in sec) to try reset the driver when the state is ERROR. Default: 5.0

Variables

These are the variables to be accessed in the controller, read and written through the driver. They are defined by a dict that may include several definitions following the next format {address: {'datatype':str, 'size':int, 'operation':str}:

• address (str): It can be used as name, tag, id, or simply to identify the variable.
• datatype (str): It is used to define the variable data type (bool, byte, int, word, dword, qword, float, str).
• size (int): It defines if the variable is an array. If not defined it is asumed is not an array or dimension 1.
• operation (str): It defines if the variable should be written or read by the driver in the controller (read, write).

An example of two variables input and output definition:

{
  "input": {
    "datatype": "byte",
    "size": 1,
    "operation": "write"
  },
  "output": {
    "datatype": "byte",
    "size": 2,
    "operation": "read"
  }
}

Result

Now, combining these two blocks together, a complete SETUP msg would look like the following example:

{
  "parameters": {
    "rpi": 35,
    "force_write": 0.5,
    "ip": "192.168.0.1",
    "port": 1234
  },
  "variables": {
    "input": {
      "datatype": "byte",
      "size": 1,
      "operation": "write"
    },
    "output": {
      "datatype": "byte",
      "size": 2,
      "operation": "read"
    }
  }
}

tip

You will find specific examples of the setup_data, update_input and update_output in the different drivers documentation.