PID Control Object (with questions)

Hello @Wilberforce,

Yes, I am using esp8266 (wemos d1 mini).
I have put the program on "save on send" option.
The script should be small in size as follows

I2C1.setup({scl:D5,sda:D4, bitrate:100000});
var PID = require('pid-controller');
var bme = require("BME280").connect(I2C1);
var WIFI_NAME = "xxx";
var WIFI_OPTIONS = { password : "xxx" };
var MQTT_HOST = "192.168.0.156";
var PATH = "/mydevice/";
var LED = D13;
var RELAY = D12;
var BTN = D0;
var mqtt;
var wifi;
var hum = 20,
    humSetpoint = 55;

var Kp = 100,
    Ki = 0,
    Kd = 0;

var ctr;
var timeframe = 30000;
var dacMin = 100;
var dacMax = 3000;

wifi = require("Wifi");
var nodeID = wifi.getIP().mac;
nodeID = nodeID.replace(/:/g, "");
nodeID = nodeID.toUpperCase();

function updatePid() {
  hum = bme.getData().humidity;
  hum = hum.toFixed(1);
  hum = E.clip(hum, 10, 100);
  ctr.setInput(hum);
  if (ctr.compute()) {
    var dataDac = ctr.getOutput();
    dataDac = E.clip(dataDac, dacMin, dacMax);
    I2C1.writeTo(0x60, [dataDac >> 8, dataDac]);
    setTimeout(function() {
      var adc = analogRead().toFixed(3);
      var bufText = "{\"H\":"+hum+",\"DAC\":"+dataDac+",\"ADC\":"+adc+"}";
      console.log(bufText);
      mqtt.publish(PATH+"status",bufText);
    }, 3000);
  }
}

function setState(v) {
  RELAY.write(v);
  LED.write(!v);
  mqtt.publish(PATH+"status", v?1:0);
}

function mqttMessage(pub) {
  console.log("MQTT=> ",pub.topic,pub.message);

  if (pub.topic == PATH+"set") {
    setState(pub.message!=0);
  }
  if (pub.topic == PATH+"eval") {
    try {
      mqtt.publish(PATH+"response", eval(pub.message));
    } catch(e) {
      mqtt.publish(PATH+"exception", e.toString());
    }
  }
}

function mqttConnect() {
  mqtt = require("MQTT").connect({
    host: MQTT_HOST,
    client_id : nodeID,
  });
  mqtt.on('connected', function() {
    console.log("MQTT connected");
    setTimeout(function() {      
      mqtt.subscribe(PATH+"#");
    }, 1000);
  });
  mqtt.on('publish', mqttMessage);
}


function onInit() {
  ctr = new PID(hum, humSetpoint, Kp, Ki, Kd, 'direct');
  ctr.setSampleTime(timeframe);
  ctr.setOutputLimits(dacMin, dacMax);
  ctr.setMode('auto');
  digitalWrite(D16,0);
  console.log("Connecting WiFi");
  setInterval(updatePid, timeframe);
  setInterval(function() {
    if (!mqtt) return;
    if (!mqtt.connected) {
      console.log("MQTT disconnected... reconnecting.");
      mqtt.connect();
    }
    digitalWrite(D16, 1);
    setTimeout( function d16() {
      digitalWrite(D16,0);
    }, 300);
  }, 60*1000);

  wifi = require("Wifi");
  wifi.on('connected',function() {
    console.log("Connected to WiFi");  
  });
  wifi.on('disconnected',function() {
    console.log("Disconnected from WiFi");  
  });
  wifi.setHostname("MYDEVICE");
  wifi.stopAP();
  wifi.connect(WIFI_NAME, WIFI_OPTIONS,
               function(ap){ 
    console.log("Successful connect.");
  });
  // wait, and connect MQTT
  setTimeout(function() {
    console.log("MQTT connecting");
    mqttConnect();
  }, 10000);
}

and bellow is the error message

 ____                 _
|  __|___ ___ ___ _ _|_|___ ___
|  __|_ -| . |  _| | | |   | . |
|____|___|  _|_| |___|_|_|_|___|
         |_| espruino.com
 1v99 (c) 2018 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate
Flash map 4MB:1024/1024, manuf 0xc8 chip 0x4016
>
=undefined
Running onInit()...
Connecting WiFi
Successful connect.
Connected to WiFi
MQTT connecting
ERROR: Error processing Serial data handler - removing it.
Execution Interrupted during event processing.
New interpreter error: CALLBACK,LOW_MEMORY,MEMORY
>