modbus-serial - npm Package Compare versions

Comparing version 1.2.0 to 1.2.1

index.js

@@ -61,3 +61,3 @@ /**
  * Parse the data for a Modbus -
- * Read Input Registers (FC=04)
+ * Read Input Registers (FC=04,03)
  *
@@ -77,3 +77,3 @@ * @param {buffer} data the data buffer to parse.
     if (next)
-        next(null, {"data": contents});
+        next(null, {"data": contents, "buffer": data.slice(3, 3 + length)});
 }
@@ -192,4 +192,6 @@
                  
-                // Read Input Registers (FC=04)
-                if (code == 4) {
+                /* Read Input Registers (FC=04)
+                 * Read Holding Registers (FC=03)
+                 */
+                if (code == 4 || code == 3) {
                     _readFC4(data, next);
@@ -208,3 +210,3 @@ }
 /** 
- * Write a Modbus Read Input Registers (FC=04) to serial port.
+ * Write a Modbus "Read Holding Registers" (FC=03) to serial port.
  *
@@ -216,4 +218,17 @@ * @param {number} address the slave unit address.
  */
-ModbusRTU.prototype.writeFC4 = function (address, dataAddress, length, next) {
-    var code = 4;
+ModbusRTU.prototype.writeFC3 = function (address, dataAddress, length, next) {
+    this.writeFC4(address, dataAddress, length, next, 3);
+}
+
+/** 
+ * Write a Modbus "Read Input Registers" (FC=04) to serial port.
+ *
+ * @param {number} address the slave unit address.
+ * @param {number} dataAddress the Data Address of the first register.
+ * @param {number} length the total number of registers requested.
+ * @param {function} next the function to call next.
+ */
+ModbusRTU.prototype.writeFC4 = function (address, dataAddress, length, next, code) {
+    // function code defaults to 4
+    if (!code) code = 4;
     
@@ -242,3 +257,3 @@ // set state variables
 /** 
- * Write a Modbus Preset Multiple Registers (FC=16) to serial port.
+ * Write a Modbus "Preset Multiple Registers" (FC=16) to serial port.
  *
@@ -245,0 +260,0 @@ * @param {number} address the slave unit address.

package.json

 {
   "name": "modbus-serial",
-  "version": "1.2.0",
+  "version": "1.2.1",
   "description": "A pure JavaScript implemetation of MODBUS-RTU (and TCP) for NodeJS.",
@@ -5,0 +5,0 @@ "main": "index.js",

README.md

@@ -35,3 +35,3 @@ # modbus-serial
 
-This class implements FC4 "Read Input Registers" and 
+This class implements FC3 "Read Holding Registers", FC4 "Read Input Registers" and 
 FC16 "Preset Multiple Registers" of modbus-RTU.
@@ -112,3 +112,25 @@
 ```
+----
+###### Read raw buffer
+``` javascript
+var SerialPort = require("serialport").SerialPort;
+var serialPort = new SerialPort("/dev/ttyUSB0", {baudrate: 9600});
+var ModbusRTU = require("modbus-serial");
+var modbusRTU = new ModbusRTU(serialPort);
 
+modbusRTU.open();
+
+// read 2 16bit-registers to get one 32 bit number
+setTimeout(function() {
+    modbusRTU.writeFC4(1, 5, 2, function(err, data) {
+        console.log(data.buffer.readUInt32BE());
+    });
+}, 2000);
+
+// close communication
+setTimeout(function() {
+   serialPort.close();
+}, 3000);
+```
+
 #### Methods
@@ -123,2 +145,25 @@ ----
 ----
+##### .writeFC3 (unit, address, length, callback)
+Writes "Read Holding Registers" (FC=03) request to serial port.
+
+###### unit
+The slave unit address.
+
+###### address
+The Data Address of the first register.
+
+###### length
+The total number of registers requested.
+
+###### callback (optional)
+Called once the unit returns an answer. The callback should be a function 
+that looks like: function (error, data) { ... }
+```
+error - null on success, error string o/w
+data - an object with two fildes:
+    data.data: array of unsinged 16 bit registers.
+    data.buffer: raw baffer of bytes returned by slave.
+```
+
+----
 ##### .writeFC4 (unit, address, length, callback)
@@ -139,2 +184,8 @@ Writes "Read Input Registers" (FC=04) request to serial port.
 that looks like: function (error, data) { ... }
+```
+error - null on success, error string o/w
+data - an object with two fildes:
+    data.data: array of unsinged 16 bit registers.
+    data.buffer: raw baffer of bytes returned by slave.
+```
 
@@ -141,0 +192,0 @@ ----

test/test.js

@@ -21,3 +21,23 @@ 'use strict';
   
-  describe('#writeFC4() - read registers.', function () {
+  describe('#writeFC3() - read holding registers.', function () {
+    it('should read 3 registers [0xa12b, 0xffff, 0xb21a] without errors', function (done) {
+        modbusRTU.writeFC3(1, 8, 3, function(err, data) {
+            expect(err).to.be.a('null');
+            expect(data).to.have.property('data').with.length(3);
+            expect(data.data.toString()).to.equal([0xa12b, 0xffff, 0xb21a].toString());
+            done()
+        });
+    });
+    
+    it('should read raw buffer "a12bffffb21a" without errors', function (done) {
+        modbusRTU.writeFC3(1, 8, 3, function(err, data) {
+            expect(err).to.be.a('null');
+            expect(data).to.have.property('buffer');
+            expect(data.buffer.toString('hex')).to.equal("a12bffffb21a");
+            done()
+        });
+    });
+  });
+  
+  describe('#writeFC4() - read input registers.', function () {
     it('should read 3 registers [8, 9, 10] without errors', function (done) {
@@ -91,3 +111,3 @@ modbusRTU.writeFC4(1, 8, 3, function(err, data) {
   
-  describe('#writeFC4() - read registers after write.', function () {
+  describe('#writeFC4() - read input registers after write.', function () {
     it('should read 3 registers [42, 128, 5] without errors', function (done) {
@@ -94,0 +114,0 @@ modbusRTU.writeFC4(1, 8, 3, function(err, data) {

test/testport.js

@@ -14,3 +14,4 @@ 'use strict';
     // simulate 14 registers
-    this._registers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13];
+    this._registers = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+    this._holding_registers = [0,0,0,0,0,0,0,0, 0xa12b, 0xffff, 0xb21a ];
     events.call(this);
@@ -84,2 +85,22 @@ }
     
+    // function code 3
+    if (functionCode == 3) {
+        var address = buf.readUInt16BE(2);
+        var length = buf.readUInt16BE(4);
+        
+        // if length is bad, ignore message
+        if (buf.length != 8) {
+            return;
+        }
+        
+        // build answer
+        buffer = new Buffer(3 + length * 2 + 2);
+        buffer.writeUInt8(length * 2, 2);
+        
+        // read registers
+        for (var i = 0; i < length; i++) {
+            buffer.writeUInt16BE(this._holding_registers[address + i], 3 + i * 2);
+        }
+    }
+    
     // function code 4
@@ -86,0 +107,0 @@ if (functionCode == 4) {

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Improved metrics

Total package byte prevSize

29704

increased by16.38%

Number of package files

12

increased by9.09%

Lines of code

668

increased by12.08%

Number of lines in readme file

205

increased by33.12%

No dependency changes