Submit your email address to get a link for quick download on your desktop and get started!
There are many instances where the ability to troubleshoot problems in serial interfaces and devices can be important. Many industrial and commercial devices such as automation controllers, medical monitoring equipment, and scientific instruments make use of serial ports for communication. It can be quite challenging to identify the underlying issues, and we describe some common ones in our RS232 troubleshooting guide.
The most important item required for this type of problem resolution is a quality tool that can provide the information required to address the issue. Here’s where an excellent app like Serial Port Tester can save you time and trouble when tracking down serial communication problems.
This article discusses the features of this software solution and walks you through this very effective way of how to check serial port communication.
Serial Port Tester is a serial communication tool that can display and capture all data traveling through a system’s COM ports. Developers and testers of serial apps and devices are able to analyze all port activity from the software’s logs, negating the need for manual documentation.
This application offers a host of features that set it ahead of the competition. An intuitive and user-friendly interface enables the user to take advantage of all of the software’s features. These include the ability to view data in four different modes, a built-in terminal for sending data, and advanced search and filtering capabilities.
Serial Port Tester supports the RS232, RS422, RS485, Modbus and many other serial communication protocols. You can also export data to a file or copy it to the clipboard from within the application.
Modbus protocol is very broadly implemented, mainly the serial versions of it (RTU and ASCII ones). The most common way of using Modbus is Modbus RTU. Are you developing software that communicates with electronic devices through Modbus RTU? In this case, you will surely appreciate a high-quality Modbus RTU software for monitoring and analysis of data sent via this protocol.
For this demonstration, we will use Electronic Team’s Serial Port Tester as our COM port testing application. We will walk through a few typical use cases for the software.
A loopback test involves sending and receiving data from the same COM port. A signal is initiated from a device and returned to it after traversing part or all of a network.
The loopback test is providing information about:
It’s an important method for troubleshooting serial communication problems and make sure that the COM port works correctly.
It often employed to address issues with RS232, RS422, and RS485 communications. You can emulate a communication circuit with a loopback test and eliminate the need for extra equipment to track down problems. Some modification of the port’s pins needs to be done in order to allow two-way communication on the same interface.
A simple loopback test of an RS-232 interface requires connecting the transmit (TXD) pin to the receive (RXD) pin. The differential pairs of the RS-422 and RS-485 protocols demand the connection of the TXD+ pin to the RXD+ and the TXD- to the RXD-.
Hardware flow control can be incorporated into more advanced loopback tests by making additional pin connections. Similarly to the transmit and receive pins, in an RS-232 port you connect the CTS and RTS pins to the DTR and DSR pins. For RS-422 and RS-485 interfaces, you connect the CTS+ with the RTS+ and CTS- with RTS-.
Below you can see the pinout diagram of a common serial connector, DE-9:
For a simple loopback test (marked red in Fig. 2,3 below), you connect:
For a loopback test with a hardware flow control (marked blue in Fig. 2,3), you connect:
Pin numbers are often engraved on the connector casing. This is how pins are identified in the DE9 connector of the RS-232 serial port:
While performing loopback tests with HyperTerminal is convenient, there are more efficient ways to test RS-232 ports.
There are limitations to this serial loopback test which inhibit your ability to debug issues that arise in hour serial communication. Windows 7 and 10 only support the paid and private version of HyperTerminal which may impact your decision to use it as your testing platform.
Many methods and strategies can be used in an effort to diagnose and resolve serial communication problems. We have looked at some of the most popular alternatives. We believe Electronic Team’s Serial Port Tester offers the best solution based on its versatility and powerful suite of features. It provides an alternative to HyperTerminal and can be used as Modbus testing software. It is a valuable tool for individuals involved in the development and testing of serial devices and applications.