Common communication problems with serial device servers used in data loggers

The data logger can record available data, but if you can't retrieve it, then the data won't fully play its role. In order to ensure the data can be retrieved successfully, it is necessary to resolve issues that may arise when communicating from the serial device server to the data logger. The following text summarizes six most common problems and explains how to solve these problems easily.

Q1:Power connection

Most data loggers require 10 to 16 V to connect to the power input, while a good power supply is between 12 and 14 V. In order to ensure that the data logger gets the power needed, make sure the logger is not powered off. By this way, some data logger models are easily implemented by illuminating them as they flash during activity. Even if your data logger does not have this feature, you can still use a voltmeter to check the voltage at the power input.


Q2:Serial connection

Must have the correct serial connection between the PC and the data logger. For example, some data loggers have two types of ports, and it is important to use the correct interface for the connected ports. Most of the data loggers are 9-pin serial ports, which are CS I / O and RS232 respectively. By using the RS232 serial port, the RS232 port between the PC end and the data logger can be connected, or use the USB to RS232 serial cable for conversion. If it is connected to a CS I / O port, you must also use a RS232 to CS I / O converter, such as the SC32B  opto-isolated RS-232 interface.


Q3:Baud rate selection

The baud rate selected in the software must match the baud rate of the data logger serial port. For example, some data records are 9600 baud rate, and some have a baud rate of 115200, which means that the 115200 starts to use automatic baud rate. The auto-baud selection attempts to automatically adjust the baud rate to match the PC device. After the connection is successful, you can change the baud rate setting of the serial port on the data logger.


Q4:COM port selection

The COM port you select in the software must match the physical port on the PC used to connect. This is rarely a problem on older computers with embedded serial ports because the port is almost always COM1 and has no change. However, most of us currently use USB to RS232 serial cable, and Windows assigns a COM number to the cable. Windows usually assigns different COM port numbers to the cable based on different inserted USB ports. Nonetheless, depending on the driver, you can specify the port number to use. Invalid COM port selection is one of the common communication problems:

(1) An error occurs when invalid COM port is selected;

(2) Use the list of COM ports available in the software to verify the port number assigned to the cable;

(3) USB to RS232 cable in the list of available COM ports;

(4) If your USB to RS-232 cable does not appear in the list of available COM ports, check if the USB driver is properly installed.


Q5:COM port availability

The COM port must be available and not yet used by other software programs. When a software opens a COM port, Windows prevents all other software from accessing it. Attempt to use the opened COM port.


Q6:PakBus address selection

The address specified in the software settings must match the address of the data logger. Use the default address 1 of the data logger, if you previously used the same computer that was successfully connected to the data logger, the settings might be correct. If you are unsure of the destination address of the data logger, you can use the device configuration utility program to check the address of the data logger when you connect.