Add PID Controller node

function/PID/pidcontrol.js

@@ -0,0 +1,48 @@
+/**
+ * Copyright 2015 IBM Corp.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ **/
+
+module.exports = function(RED) {
+    "use strict";
+    var Controller = require('node-pid-controller');
+
+    function PIDcontrolNode(n) {
+        RED.nodes.createNode(this,n);
+        this.target = n.target;
+        this.kp = n.kp;
+        this.ki = n.ki;
+        this.kd = n.kd;
+        var node = this;
+        node.ctr = new Controller(node.kp, node.ki, node.kd);
+        node.ctr.setTarget(node.target);
+        this.status({fill:"blue",shape:"dot",text:"set point:"+node.target});
+        var tgt = node.target;
+
+        this.on("input",function(msg) {
+            if (msg.hasOwnProperty("setpoint")) {
+                tgt = Number(msg.setpoint);
+                node.ctr.setTarget(tgt);
+                this.status({fill:"blue",shape:"dot",text:"set point:"+tgt});
+            }
+            else if (!isNaN(msg.payload)) {
+                msg.payload = node.ctr.update(Number(msg.payload));
+                msg.topic = "pid";
+                node.send(msg);
+            }
+            else { node.warn("Non numeric input"); }
+        });
+    }
+    RED.nodes.registerType("PID control",PIDcontrolNode);
+}