Fujian Lilliput Optoelectronics Technology Co.,Ltd

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Common Communication Interface Guide
- 2017/6/30 10:00:00 -

In the Internet age, communication between equipment and networking are common to be seen. In all sorts of interfaces, under what circumstances or how to choose the communication interface to make communication more convenient? This article will provide reference

In the industrial field to select the communication interface is very common, people mostly use these ports: RS232, 485, LAN, GPIB, USB, Wi-Fi, fiber and so on.


1. RS232

RS232 communication line is simple, can be carried out as long as there is cross-point bi-directional communication line with the host PC. Cable costs are low, but the transmission speed is slow, not suitable for long distance communication. Consumer PC has gradually canceled the interface, currently it is applied more in the industrial computer and some communications equipment.

After installing the system and necessary drivers for IPC, its serial port can be used directly. There are also many popular serial debugging tools can be used to test equipment in the Internet. Secondary development communication program is relatively simple.


The biggest feature of GPIB is the use of a bus to connect a number of instruments to form an automatic test system. The communication rate is low, commonly used to send control commands, suitable for small electrical interference laboratory or production field. As the ordinary PC and IPC do not provide GPIB interface commonly, you need to buy a dedicated control card, install the driver before communication.

3. LAN

At present, most of the equipment is embedded with LAN network interface, commonly known as "crystal head". Its feature is flexible networking, multi-point communication, non-limit transmission distance, high-speed and etc., making it the mainstream communication way currently.

The role of the interface itself is mainly used for routers and LAN connection. However, the LAN type is varied, so it also lead to the variety of router's LAN interface type. Different interfaces have different interface types. Common Ethernet interfaces include AUI, BNC and RJ-45 interfaces, as well as FDDI, ATM and optical interfaces. These networks have corresponding network interfaces. In the instrument industry or system integration industry, most of the engineers will choose to write commands through the network port to control the instrument.


4. USB

As the most commonly used interface, USB only has four wires, two for power supply and two  for signals, the signal is serial transmission, so the USB interface is also known as the serial port, the interface output voltage and current is +550 500mA. The maximum errors cannot exceed +/- 0.2V, which is 4.8-5.2V.

The four wires of the USB interface are generally assigned as follows: Black line: gnd Red line: vcc Green line: data + White line: data- The main function of USB is to store the data in the device or the device through the USB interface to external information Read recognition; In addition, USB is also an effective interface for  secondary development .Although USB3.0 technology has been in the field of notebook computers and other applications is very mature, but in the field of equipment, influenced by processing speed and framework, more devices use USB2.0 technology commonly.

5. Wi-Fi

In addition to the common communication interface, the wireless connection is also a very important means of communication, it is characterized by no physical line connection and fast transmission speed. There are many instruments and equipment building directly within the 802.11 wireless interface.

You can connect the instrument to a wireless router, or connect to the smartphone WIFI hotspot to form a VLAN.


OWON XDS series oscilloscope is access with Wi-Fi communication, which spare more space in measurement field. XDS supports Wi-Fi AP and Wi-Fi STA mode: Wi-Fi AP enable the device to be the hotspot source, control end connect the hotspot network and control the real time waveform through app or software. Wi-Fi STA makes the router as a center device, all the supported devices can connect to router then form a device control system. User can manage the devices through OWON’s management software. This will reduce the wasting time on device checking on site.  


Sum up

1. If it doesn’t require high communication rate, do not need long-distance communication, only one host, an instrument. Serial port can start measuring more quickly.

2. When you need to connect with the calibration source, signal generator and other instruments at the same time, and they all provide GPIB interface. Then you can change the communication mode of the device to GPIB, which can form a small network.

3. Ethernet interface is our recommended connection term, short-range communication can be solved by connecting a twisted pair directly with the IPC, or laptop. When comes to long-distance communication, you can also increase the switch to enable a host controlling a number of instruments.