Abstract: This article introduces the application of man-machine interface and thermostat communication via bus protocol, and details the communication setup of HITECH man-machine and thermostat. HITECH man-machine and thermostat communication has been widely used in a variety of industrial control applications.
Keywords: Human-machine interface, touch screen, thermostat, MODBUS protocol, fieldbus communication
Application of communication between HITECH HMI and temperature controller
Abstract:This article introduces the communication between HMI and temperature controller. They can communicate via MODBUS protocol with correct parameter configuration. This sort of application has been widely used in the industrial occasion so far.
Keyword: HMI, HITECH, touch screen, thermostat, temperature controller, modbus protocol, field-bus communication
With the development of industrial automation, thermostats no longer simply play the role of an early temperature detection indicator in various industrial sites and various types of industrial equipment. They gradually become restless and follow the temperature control system. Public processors grab power to seize the class, and even in some control systems can compete with PLC and other big names in court, self-contained faction.
In this case, let's first take a look at the killer of the thermostat:
1, easy to install, a variety of installation methods (combined with modular design), can be flexibly applied to various occasions;
2. The power supply standard is unified, and the on-site power supply is not picky;
3, in addition to measuring temperature objects, it can also measure pressure, flow, voltage, current, speed, counting and other common industrial parameters;
4, with PID and other high-level algorithms for self-tuning function, high control accuracy, fast response;
5, can carry on the multi-channel control, and can cascade network control, make the scene reachable;
6. With a universal fieldbus communication protocol, it is easy to communicate with various control devices or control systems to realize the global automation control of the site.
In the face of small and powerful thermostats, the man-machine interface (industrial touch screen) as a flower in the automation industry has long been conceited. HITECH man-machine as the leader in man-machine products, natural communication with the thermostat, of course, the following describes the HITECH man-machine and a domestic brand thermostat in the communication application.
As the saying goes, the first line of marriage is the result of thousands of miles, and the red line linking HITECH's man-machine and thermostat is the MODBUS communication protocol. MODBUS protocol has become one of the most widely used fieldbus communication protocols in industrial automation applications. Because of its simple protocol structure, reliable communication, and fast topology, it has been selected as a standard communication protocol by many controller manufacturers, which greatly simplifies the controller itself. The development of communication functions improves the competitiveness of the products themselves.
HITECH man-machine supports the standard MODBUS protocol, man-machine itself can do MODBUS master station, also can do MODBUS slave station. When communicating with the thermostat, the man-machine is the master station, and sends various instruction codes to the thermostat to perform corresponding reading and writing operations.
In this example application, a 5.7-inch monochrome HITECH man-machine model PWS6600S-P was used to communicate with the OKE thermostat.
I. Communication Settings in Human Machine Software
First of all, in HITECH human programming software ADP, select the man-machine model and the connected controller type, as shown below:
Modicon 984 (RTU; Slave) is the type of PLC in the software. This is the standard MODBUS protocol and the thermostat acts as a slave. (Note that the control area and status area addresses are deleted here, otherwise it will affect the communication.)
Communication parameters are set as shown below:
Second, the thermostat settings
On the thermostat, set the communication parameters and the channel address by the position of the dial switch. See the figure below:
Therefore, to set the thermostat to the same communication parameters as the human-machine, the dialing code should be set to 4 and 5 for ON, and the others are OFF; the channel address is 0-3.
Third, communication wiring
PWS6600S-P has two communication ports, and both support RS232 and RS485 communication methods. Communication with the thermostat generally uses RS485 mode, and supports multiple module networking communication.
Thermostat address list is as follows:
The correspondence between the temperature controller and the MODBUS protocol address in the man-machine is:
Fifth, run
The required parameters are planned on the screen with the corresponding components, the communication parameters are set, the touch screen and the temperature controller are connected with the communication line, the communication can be established after the operation, and the parameters of the thermostat can be viewed or modified on the human-machine screen. Working status. As shown below:
to sum up
In practical applications, the PWS6600S-P man-machine has stable communication with the thermostat, real-time control is good, and the interface is intuitive and easy to operate.
Since the introduction of Tianjin Luosheng Enterprise Co., Ltd. into the mainland in the 1990s, the HITECH man-machine interface has been well received by customers due to its mature technology, reliable quality, and powerful features. HITECH man-machine fully supports the standard MODBUS bus protocol and can communicate with any controller that supports this protocol. In the present situation where domestic brand controllers, thermostats, and frequency converters flourish, this is undoubtedly a great tool for domestic users to choose HITECH. HITECH will continue to use its own advantages to promote the progress of domestic industrial automation.
References:
ADP Software Programming Manual - Tianjin Luosheng Enterprise Co., Ltd.
"OKE four-channel temperature module manual" - Wuxi Oukai Electronic Control Equipment Factory
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