DEV Community: Helgayork

List of Modbus Monitoring Software

Helgayork — Thu, 22 Nov 2018 16:07:57 +0000

Eltima Software has developed Modbus Tester Software which can analyze Modbus messages that use either the RTU or ASCII protocol. An intuitive user interface and flexible advanced filtering capabilities enable you to view data in a user-friendly manner. Use of this Modbus Tester can be instrumental in developing and optimizing serial applications and in testing serial devices.

Download Serial Port Monitor

This professional-grade Modbus test software allows you to perform these functions:

Connect with serial ports that are already in use by another program. Once connected, you can begin monitoring the interface immediately. You can track issues as they occur with the real-time data display provided by the Modbus test program.
Monitor and analyze the data flow of multiple serial ports in one monitoring session. Data moving in both directions from a number of serial ports can be monitored and recorded in a combined log file. Data is captured on a first-in-first-out basis making it easy to follow the transmissions from the various ports being monitored.
This Modbus RTU tester lets you employ different data views when monitoring and analyzing your serial throughput. Choose from terminal, table, dump and line views. Additional customization can be performed using the tool’s data filters.
Perform a Modbus communication test of the data transferred to a serial device. This will enable you to determine how it will react to a variety of different commands.

Master and Slave Modbus Simulators

QmodMaster is a Qt-based application that allows you to simulate a Modbus master. This free software can be used to analyze traffic in the role of a bus monitor and includes a detailed user interface.

SimplyModbusMaster – This tool displays your data in a single window and can simulate a Modbus Master in both the RTU and ASCII protocols. Using this application lets you monitor Modbus master requests and allows you to simulate a Modbus ASCII or RTU slave device. The interface uses two windows. One is used for displaying and modifying the setting while the other presents the data.

Modbus data Sniffer - Monitoring and analyzing Modbus transmissions is the main function of this professional software solution.

Modbus Poll can simulate a Modbus master and simultaneously monitor multiple slaves or data areas. It provides users with a multiple document interface for advanced monitoring. The Test Center can be used by developers to create and send test data strings and view the results in hexadecimal format.

Serial port simulation with different programming languages

Helgayork — Tue, 16 Oct 2018 15:58:38 +0000

Main principles of serial port emulation

One of the major benefits of creating multiple virtual serial ports is the freedom afforded to developers to test and debug serial applications on computers that do not have any physical serial ports.

For instance, when developing a serial communication program the engineer will need to use at least two serial ports. Most computers on the market today have at most one serial port and many do not have any at all. Workarounds include using two machines or employing a PCI card to add a COM port to the system. Use of a serial port emulator lets a developer create as many virtual serial ports as needed on a single computer. This means that any machine that can run the emulation software can be used to develop serial software.

The emulation of COM interfaces means that software developers can dispense with complicated solutions to control resource sharing and interprocess communication. The speed of transmission between virtual ports is dependent on your system’s capacity and is not tied to the physical limitations of the serial ports.

The parameters of physical serial interfaces are fully replicated when using virtual COM ports, including strict baud-rate emulation.

Eltima Software’s Virtual COM Port Driver (VSPD) is a comprehensive virtual serial port emulator for Windows 7 as well as all later versions of the Windows OS. The tool provides the user with a robust virtual serial port emulator for 32 and 64 bit operating systems all wrapped in a very user-friendly and intuitive interface. Using this serial port emulator for Windows 10 takes advantage of the software being digitally signed with WHQL. VSPD is one of the most effective serial port emulation applications that are available to serial developers

Serial port simulation with different programming languages

Software developers know that in many cases, simulating behavior by using virtual devices can offer advantages over the use of physical devices when testing and debugging their code.

A good example is using a serial port emulator during the development of complicated serial communication systems. There are numerous virtual serial port emulators available that are usually used on the Windows operating system and allow developers to create virtual serial ports for testing purposes. Communication between RS232 or RS484 interfaces can be monitored and tested easily by using these serial port simulator applications.

Development of your own virtual port emulator is possible to assist you in monitoring serial transmissions between an application and physical serial ports. This can enable the testing of programs that usually interact with physical COM ports without requiring a physical connection to the port. Specialized apps can create a virtual null-modem cable that allows communication through pairs of virtual serial interfaces.

VSPD makes it easy to work with files and devices by supporting standard options like CreatePair, DeletePair, and SetStrictBaudrate. Here are some examples that illustrate incorporating the power of Virtual Serial Port Driver when using some pf the more popular programming languages in use today.

Delphi

Function declarations for Delphi are as follows:

Function CreatePair(Port1, Port2 : PChar) : Boolean; stdcall; external "VSPDCTL.DLL";
Function DeletePair(Port : PChar) : Boolean; stdcall; external "VSPDCTL.DLL";
Function DeleteAll : Boolean; stdcall; external "VSPDCTL.DLL";
Function SetStrictBaudrateName(Port: PChar, StrictBaudrate: Boolean) : Boolean; stdcall; external "VSPDCTL.DLL";
Function SetStrictBaudrateHandle(hPort: THandle, StrictBaudrate: Boolean) : Boolean; stdcall; external "VSPDCTL.DLL";
Function CreatePair(Port1, Port2 : PChar) : Boolean; stdcall; external "VSPDCTL.DLL";
Function DeletePair(Port : PChar) : Boolean; stdcall; external "VSPDCTL.DLL";
Function DeleteAll : Boolean; stdcall; external "VSPDCTL.DLL";
Function SetStrictBaudrate(Port: PChar, StrictBaudrate: Boolean) : Boolean; stdcall; external "VSPDCTL.DLL";
Function SetBreak (Port: PChar, bBreak: Boolean) : Boolean; stdcall; external "VSPDCTL.DLL";
Function QueryBus (InBuffer: Pointer, sizeInBuffer: Integer, OutBuffer: Pointer, sizeOutBuffer: Integer) : Boolean; stdcall; external "VSPDCTL.DLL";
Function SetWiring (Port: PChar Buffer: Pointer, sizeBuffer: Integer) : Boolean; stdcall; external "VSPDCTL.DLL";>

ArmAccess can be loaded either statically or dynamically. To use dynamic loading, make use of this same code:

Function CreatePairFn(PortName1, PortName2 : String) : Boolean;
Type TCreatePair = function(Port1, Port2 : PChar) : Boolean; stdcall;
Var Handle : THandle;
CreatePair : TCreatePair;
Begin
 CreatePairFn := False;
 Handle := LoadLibrary("VSPDCTL.DLL");
 If (Handle <> 0) Then
  Begin
   @CreatePair:=GetProcAddress(Handle, "CreatePair");
   If (CreatePair <> Nil) Then
    CreatePairFn := CreatePair(PChar(PortName1), PChar(PortName2));
    FreeLibrary(Handle);
  End;
End;

C/C++

To use the virtual port emulator, after loading the DLL file dynamically choose and call your desired functions.. Here’s how it looks in Visual C++ :

typedef bool (stdcall *CreatePairFn)(char *Port1, char *Port2);
typedef bool (stdcall *DeletePairFn)(char *Port);
typedef bool (stdcall *DeleteAllFn)(void);
typedef bool (stdcall *SetStrictBaudrateFn) (char *Port, bool StrictBaudrate);
typedef bool (stdcall *SetBreakFn) (char *Port, bool bBreak);
typedef bool (stdcall *QueryBusFn) (void* InBuffer, long sizeInBuffer, void* OutBuffer, long sizeOutBuffer);
typedef bool (stdcall *SetWiringFn) (char *Port, void *Buffer, long sizeBuffer);
typedef bool (stdcall *SetAccessListFn) (char *Port, void *Buffer, long sizeBuffer);

typedef bool (stdcall *CreatePairExFn)(char *Port1, char *Port2, char * UserSession);
typedef bool (stdcall *CreatePairWFn)(WCHAR *Port1, WCHAR *Port2);
typedef bool (stdcall *CreatePairExWFn)(WCHAR *Port1, WCHAR *Port2, WCHAR * UserSession);
typedef bool (stdcall *DeletePairWFn)(WCHAR *Port);
typedef bool (stdcall *SetStrictBaudrateWFn) (WCHAR *Port, bool StrictBaudrate);
typedef bool (stdcall *SetBreakWFn) (WCHAR *Port, bool bBreak);
typedef bool (stdcall *SetWiringWFn) (WCHAR *Port, void *Buffer, long sizeBuffer);
typedef bool (stdcall *SetAccessListWFn) (WCHAR *Port, void *Buffer, long sizeBuffer);
typedef bool (stdcall *DeletePairExFn)(char *Port, char * UserSession);
typedef bool (stdcall *DeletePairExWFn)(WCHAR *Port, WCHAR * UserSession);

typedef bool (stdcall *GetUserSessionFn)(char *Session, int &iSize);
typedef bool (stdcall *GetUserSessionWFn)(WCHAR *Session, int &iSize);

typedef bool (stdcall *SetStrictBaudrateExWFn) (WCHAR *Port, WCHAR * UserSession, bool StrictBaudrate);
typedef bool (stdcall *SetStrictBaudrateExFn) (char *Port, char * UserSession, bool StrictBaudrate);
typedef bool (stdcall *SetBreakExWFn) (WCHAR *Port, WCHAR * UserSession, bool bBreak);
typedef bool (stdcall *SetBreakExFn) (char *Port, char * UserSession, bool bBreak);
typedef bool (stdcall *SetAccessListExWFn) (WCHAR *Port, WCHAR * WCHAR, void *Buffer, long sizeBuffer);
typedef bool (stdcall *SetAccessListExFn) (char *Port, char * WCHAR, void *Buffer, long sizeBuffer);

bool CreateVSPair(char *Port1, char *Port2) {
OSVERSIONINFO VersionInfo;
HINSTANCE libInst;
libInst = LoadLibrary(VSPDCTL.DLL);
if (!libInst)
   return false; /* Couldn't load library */
/* Substitute the typedefs above for functions other than CreatePairFn */
CreatePairFn CreatePair=(CreatePairFn)GetProcAddress(libInst, CreatePair);
if (CreatePair==0) return false; /* Couldn`t find function */
returnvalue=CreatePair(Port1, Port2); /* For example, Port1 = COM5 and Port2 = COM6 */
FreeLibrary(libInst);
return returnvalue;
};

Visual Basic

In order to use VSPD with Visual Basic, paste these lines into your source file:

Declare Function CreatePair Lib "VSPDCTL.DLL" (ByVal Port1$, ByVal Port2$) As Boolean
Declare Function DeletePair Lib "VSPDCTL.DLL" (ByVal Port$) As Boolean
Declare Function DeleteAll Lib "VSPDCTL.DLL" () As Boolean
Declare Function SetStrictBaudrateName Lib "VSPDCTL.DLL" (ByVal Port$, ByVal StrictBaudrate As Boolean) As Boolean
Declare Function SetStrictBaudrateHandle Lib "VSPDCTL.DLL" (ByVal Handle As Long, ByVal StrictBaudrate As Boolean) As Boolean
Declare Function CreatePair Lib "VSPDCTL.DLL" (ByVal Port1$, ByVal Port2$) As Boolean
Declare Function DeletePair Lib "VSPDCTL.DLL" (ByVal Port$) As Boolean
Declare Function DeleteAll Lib "VSPDCTL.DLL" () As Boolean
Declare Function SetStrictBaudrate Lib "VSPDCTL.DLL" (ByVal Port$, ByVal StrictBaudrate As Boolean) As Boolean
Declare Function SetBreak Lib "VSPDCTL.DLL" (ByVal Port$, ByVal bBreak As Boolean) As Boolean
Declare Function QueryBus Lib "VSPDCTL.DLL" (ByVal InBuffer As String, sizeInBuffer As Long, ByVal OutBuffer As String, sizeOutBuffer As Long) As Boolean
Declare Function SetWiring Lib "VSPDCTL.DLL" (ByVal Port1$, ByVal Buffer As String, sizeBuffer As Long) As Boolean

If you store the VSPDCTL.DLL in your application’s directory, you can make direct function calls.

RS232 null modem pinout and wiring

Helgayork — Fri, 28 Sep 2018 08:01:03 +0000

What is a null modem?

Null modems are used to connect two computers without modems via the RS232 protocol. Originally developed to allow teletype machines to connect to each other through their modems, the RS232 protocol is perfect for use in null modems.

The asymmetric connectivity using the RS232 protocol requires a data source or consumer at one end of the connection and a modem at the other end. There is no standard wiring scheme for an RS232 null modem and you will find that many different variations are used in practice. The reception and transmission lines in a null modem are connected crosswise to enable data transmission in both directions.

The most common use of null modems is to enable older laptops and computers to exchange data. Without a network card or USB port, null modem connections and null modem emulators are the only methods that can be used for data transmission between these legacy machines.

What is a null modem cable?

It might be obvious that you would create null modem connections by using a null modem cable.

What distinguishes a null modem cable from any other cable? Specifically, a null modem cable is constructed using three lines. Two of the lines take care of transmitting data with the third wire acting as a signal ground.

Null modem pinout and wiring

Based on the software you are using when transmitting over a null modem cable, you may need the connection to provide an authenticating handshake.

Here are the most common schemes of null modem cables.

Here is the RS232 cable wiring configuration that is recommended by Microsoft that includes full authentication handshaking.

This is the industry standard for RS232 null modem connections. It uses a cable developed by Microsoft that is manufactured with seven wires.

Virtual Null Modem Emulator

Null modem cables do not provide for high-speed data transmission. Theoretically, the maximum throughput speed of a null modem connection is limited by the speed of the serial port that connects it to the computer. This maximum of 115 kb/s is never reached as the transfer speed is impacted by the length of cable used to make the connection.

Higher transmission speeds can be achieved by using the specialized software of a null modem emulator. This application creates a virtual null modem connection between two computers. It employs a virtual null modem cable to connect to the machine’s serial ports.

Virtual null modem software allows you to create pairs of virtual COM ports. The software enables bi-directional data transmission between serial ports. Data that is transmitted to one COM port in the pair is also simultaneously received by the other port in the pair.

Using virtual null modem software to transmit data is a much more efficient method of communication than that which can be achieved with a physical null modem cable.

A quality null modem emulator such as Virtual Com Port Driver by Eltima allows you to emulate baud rate and enables full HandFlow control. This application supports all standard line signals like RTS/CTS, DRT/DSR, RING, and ERROR. A virtual null modem emulator also enables you to simulate line breaks in serial connections.

Using Several Apps Simultaneously to Control a Ham Radio Transceiver

Helgayork — Fri, 21 Sep 2018 15:00:19 +0000

A problem faced by a large number of Ham radio operators is the fact that only one serial port at a time can be accessed through the Windows operating system. If you want to use several applications at the same time with the same physical COM interface you will need to employ dedicated serial port splitting software.

Some standard issues encountered by Ham radio amateurs and the best ways to resolve them.

The station control software running on your PC needs access to the Ham radio transceiver through the COM port where it is attached. Other software such as a station book or logging software also needs access to the transceiver through the same serial port.

The native operating system does not allow the simultaneous connection forcing you to use only one app at a time as a workaround. This is the usual way of getting around this issue but it is not a very efficient or effective solution.

A better way to allow two programs to interact with the same serial port is to use a COM port splitter application such as Virtual COM Port Driver PRO.

Using this software solution enables you to take a single physical serial port and split it into a number of virtual copies. This allows the simultaneous connection of all your serial programs to the same real port. The virtual copies appear as distinct COM ports when in reality they are all employing the same physical interface. Using serial port splitting software will let you connect as many programs as you like to your Ham radio transceiver.

Virtual Serial Port Driver PRO can be used with 32 and 64-bit versions of Windows 10 as well as many older iterations of the Windows operating system.

Here is another case where Virtual COM Port Driver PRO can prove to be extremely useful.

If you have CW Skimmer, MixW, or some other specialized software running and want to use your logging program to control your radio, you again run into the problem of requiring simultaneous access to the same port. Using serial port splitter software this is an easy problem to resolve. Each application can simply attach to a virtual copy of your interface.

You also might consider Serial Sniffer by Eltima for your data logging software solution. It enables you to trace, debug, and monitor all of the serial ports in your environment and display all of the logged data in a number of convenient formats.

Another challenging situation is when a GPS user would like to share a single NMEA (National Marine Electronics Association) information stream with several applications.

Once again, we need the ability to split a single data stream into multiple streams or face the prospect of using only one application at a time. Virtual COM Port Driver PRO is an excellent and simple solution to this problem by allowing you to create as many virtual serial ports as you need from a single physical interface. This lets you share the information from the GPS unit with as many applications as you wanted. All programs will have access to the same data at the same time.

As demonstrated above, you can see that Virtual Serial Port Driver PRO is one of the best Com port splitters available. Its advanced features can be very helpful to Ham radio operators using a PC to interact with their equipment. With Virtual Serial Port Driver PRO, you can:

split one serial data stream into multiple exact copies;
combine serial data from multiple sources into a single data flow;
use the same serial interface to connect to multiple serial applications;
create an unlimited number of virtual serial ports on your system;
merge multiple real and virtual COM ports in such a way that several hardware - devices and serial applications can exchange data with each other simultaneously.

Using Serial Port Test Software for RS232 Device Activity Analysis

Helgayork — Wed, 19 Sep 2018 13:46:22 +0000

You will need to monitor and analyze serial port activity occasionally if you want to work with serial ports. Monitoring the data sent and received by RS232/422/485 ports--especially when one is setting up equipment—is a good way to spot troubles easily should they arise.

Currently, there is no serial port testing tool on Windows OS to analyze data sent and received by COM ports. However, you can use a program that will allow you to monitor and analyze COM port activity.

There is a less stressful way to track problems that could arise during an application or driver development process (or while you are testing, debugging and optimizing your application). Eltima Software has created Serial Port Tester that provides a way to analyze, monitor, display and log data produced by RS232/422/485 COM ports.

The RS232 testing software is a simple serial port testing tool that allows you to:

Instantly connect with and monitor serial ports already being used by an application. Our COM port testing software provides real-time reporting that maximizes all opportunities to troubleshoot any issues that may arise.
Simultaneously view data in multiple modes (i.e., table, line, terminal or dump view). Various options are available to display recorded data. For instance, you can select various filters to restrict what data you would like to see.
Simultaneously monitor multiple COM ports during the same rs232 tester software analysis. Analyzing data is easier to do this way when using a com port test program because the data compiled from simultaneous COM port monitoring is displayed in one log (first-in, first-out approach).
Emulate the transference of serial port data to a serial device when viewing data in terminal mode. Data is sent on behalf of a monitored application via decimal, binary, hexadecimal, string or mixed format to allow you to monitor the activity of a serial device when certain commands are used.

Find out more about RS485 protocol Analyzer (for programming and debugging of RS485 port communication).

See additional information on how to read serial port data.