separate transaction read and write counters

yaacov · May 9, 2017 · b0edd87 · b0edd87
1 parent 6cce55a
commit b0edd87
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Showing 3 changed files with 19 additions and 17 deletions.
diff --git a/index.js b/index.js
@@ -135,7 +135,7 @@ function _readFC16(data, next) {
  * @private
  */
 function _writeBufferToPort(buffer) {
-    var transaction = this._transactions[this._port._transactionId];
+    var transaction = this._transactions[this._port.transactionsCounter];
 
     this._port.write(buffer);
     if (transaction) {
@@ -207,8 +207,9 @@ ModbusRTU.prototype.open = function(callback) {
             if (callback)
                 callback(error);
 
-            /* init ports transaction id */
+            /* init ports transaction id and counter */
             modbus._port._transactionId = 1;
+            modbus._port.transactionsCounter = 1;
 
             /* On serial port success
              * register the modbus parser functions
@@ -380,7 +381,7 @@ ModbusRTU.prototype.writeFC2 = function(address, dataAddress, length, next, code
     code = code || 2;
 
     // set state variables
-    this._transactions[this._port._transactionId] = {
+    this._transactions[this._port.transactionsCounter] = {
         nextAddress: address,
         nextCode: code,
         nextLength: 3 + parseInt((length - 1) / 8 + 1) + 2,
@@ -433,7 +434,7 @@ ModbusRTU.prototype.writeFC4 = function(address, dataAddress, length, next, code
     code = code || 4;
 
     // set state variables
-    this._transactions[this._port._transactionId] = {
+    this._transactions[this._port.transactionsCounter] = {
         nextAddress: address,
         nextCode: code,
         nextLength: 3 + 2 * length + 2,
@@ -473,7 +474,7 @@ ModbusRTU.prototype.writeFC5 = function(address, dataAddress, state, next) {
     var code = 5;
 
     // set state variables
-    this._transactions[this._port._transactionId] = {
+    this._transactions[this._port.transactionsCounter] = {
         nextAddress: address,
         nextCode: code,
         nextLength: 8,
@@ -518,7 +519,7 @@ ModbusRTU.prototype.writeFC6 = function(address, dataAddress, value, next) {
     var code = 6;
 
     // set state variables
-    this._transactions[this._port._transactionId] = {
+    this._transactions[this._port.transactionsCounter] = {
         nextAddress: address,
         nextCode: code,
         nextLength: 8,
@@ -560,7 +561,7 @@ ModbusRTU.prototype.writeFC15 = function(address, dataAddress, array, next) {
     var i = 0;
 
     // set state variables
-    this._transactions[this._port._transactionId] = {
+    this._transactions[this._port.transactionsCounter] = {
         nextAddress: address,
         nextCode: code,
         nextLength: 8,
@@ -615,7 +616,7 @@ ModbusRTU.prototype.writeFC16 = function(address, dataAddress, array, next) {
     var code = 16;
 
     // set state variables
-    this._transactions[this._port._transactionId] = {
+    this._transactions[this._port.transactionsCounter] = {
         nextAddress: address,
         nextCode: code,
         nextLength: 8,

diff --git a/ports/tcpport.js b/ports/tcpport.js
@@ -22,6 +22,7 @@ var TcpPort = function(ip, options) {
     this.ip = ip;
     this.openFlag = false;
     this.callback = null;
+    this.transactionsCounter = 1;
 
     // options
     if (typeof(options) === "undefined") options = {};
@@ -115,16 +116,16 @@ TcpPort.prototype.write = function(data) {
         return;
     }
 
-    // get next transaction id
-    var transactionsId = (this._transactionId + 1) % MAX_TRANSACTIONS;
-
     // remove crc and add mbap
     var buffer = new Buffer(data.length + MIN_MBAP_LENGTH - CRC_LENGTH);
-    buffer.writeUInt16BE(transactionsId, 0);
+    buffer.writeUInt16BE(this.transactionsCounter, 0);
     buffer.writeUInt16BE(0, 2);
     buffer.writeUInt16BE(data.length - CRC_LENGTH, 4);
     data.copy(buffer, MIN_MBAP_LENGTH);
 
+    // set next transaction id
+    this.transactionsCounter = (this.transactionsCounter + 1) % MAX_TRANSACTIONS;
+
     // send buffer to slave
     this._client.write(buffer);
 

diff --git a/test/ports/tcpport.test.js b/test/ports/tcpport.test.js
@@ -57,8 +57,8 @@ describe("Modbus TCP port", function() {
             port.open(function() {
                 port.write(new Buffer("1103006B00037687", "hex"));
 
-                if (port._client._data.equals(new Buffer("0000000000061103006B0003", "hex"))) {
-                    port._client.receive(new Buffer("000000000006110366778899", "hex"));
+                if (port._client._data.equals(new Buffer("0001000000061103006B0003", "hex"))) {
+                    port._client.receive(new Buffer("000100000006110366778899", "hex"));
                 }
             });
         });
@@ -71,8 +71,8 @@ describe("Modbus TCP port", function() {
             port.open(function() {
                 port.write(new Buffer("1103006B00037687", "hex"));
 
-                if (port._client._data.equals(new Buffer("0001000000061103006B0003", "hex"))) {
-                    port._client.receive(new Buffer("000100000005118304", "hex"));
+                if (port._client._data.equals(new Buffer("0002000000061103006B0003", "hex"))) {
+                    port._client.receive(new Buffer("000200000005118304", "hex"));
                 }
             });
         });
@@ -81,7 +81,7 @@ describe("Modbus TCP port", function() {
     describe("#write", function() {
         it("should write a valid TCP message to the port", function() {
             port.write(new Buffer("1103006B00037687", "hex"));
-            expect(port._client._data.toString("hex")).to.equal("0002000000061103006b0003");
+            expect(port._client._data.toString("hex")).to.equal("0003000000061103006b0003");
         });
     });