5.2 Node-RED – Reading Parameters

This section is about reading parameter data from an IO-Link device using Node-RED. The target is the creation of a specific Node-RED node for the write read of the parameter’s index and sub-index.

Starting point is the configuration web interface. If a parameter is readable (Read only, Read/Write), the Node-RED node creation link is shown at the variable in the “Parameter section:

In the new tab that opens, click on “Copy to clipboard”:

In the Node-RED Flows Workspace, import the node (ether with the menu or CTRL-I).

Paste the content of the clipboard to the node/flow JSON box:

The specific node is the imported into Node-RED:

• The Read Trigger Input starts the data read action. No specific data needs to be written to the port.
• The Error Number and Error Text hold the error number (see 8.1 Error Codes)
• Output is the data that is read from the parameter. For datatypes like Numbers or Strings, this is usually the data that was written. For more complex datatypes like BLOB (represented by OctetString data), this might be formatted data.

Numbers and strings are read in the native Javascript format.

Octet Stings and buffers are provided in OctetSting format.