How to identify which instance of node is this

i made one custom node named as "PLC", if after deploying flows there are 5 nodes of PLC is there on flows
In JS file of PLC node i want to know what is number of current node out of 5


When inside the node's code, there are several sections.

// This part is common - all instances share this but nothing here is 
// shared with Node-RED by default

module.exports = fuction(RED) {

   // This is also common to all instances 

   RED.nodes.registerType('nodeName', function(config) {
      // Everything in here is specific to a single instance.
      // you don't need to know the ID of the instance
      // just remember that every variable you create here is actually created once
      // per instance and they will be completely independent from any other instance

   // and here we are back to code that is common across all instances