【 Weak current college 】 building automatic control system of quality control on 2---Power By 【 China power house network 】

4 construction quality control

Construction phase of the construction process and related construction and acceptance of phased construction, according to the quality assurance system for quality control. Doing a power tubes, wire, cable laying and subtle works of construction records and acceptance. In understanding the scene building automatic control system of building environment, as well as other professions on the basis of the construction progress, according to design drawings and specifications for construction. In addition to conventional engineering construction quality management, building automatic control system should focus on the following aspects of quality control.

4.1 Checkup and technology gives the low-down

Checkup is a building automation system is one of the important aspects of construction, can be seen through the checkup this specialty and other professional drawings there are conflicts, timely adjustments. And through technology gives the low-down the construction methods and construction elements to direct construction of personnel to ensure continuity of construction requirements, ensure that the construction quality.

4.2 interface aspects in construction process

Building automatic control system and charged device interface includes two, one is the monitor signal dry contact way access DDC, another is the adoption of the communication interface point-to-point or bus mode access building automatic control system. Dry contact way seems simpler, more reliable, deficiencies is the acquisition of less use of communication interface can overcome the shortcomings of dry contact, but more difficult to implement, subject to the communication protocol is a standard, manufacturers are open coding tables to such constraints.

4.2.1 hardware interface

Since building automatic control system interfaces involved in HVAC, plumbing, lighting, electrical, and other professional, therefore, the relevant device before ordering to owners interface requirements and actively explore with the device's interface solution, avoiding the waste of funds, while clearly the responsibilities of the parties and work content, prevent problems, deal with each other, thus realizing the integrity of the building automation system. Following the design of power distribution control box as an example to illustrate the interface.

Power distribution control box within the local and remote switch and control with isolated intermediate relay (passive or active AC220V), local manual control, remote by building automatic control system of the DDC to power distribution control device to issue remote reboot/shutdown signal and is receiving power distribution control box returns the running state, thermal relay overload signals and local/remote control transfer switch status signals. Local DDC power (AC220V) provided by the distribution control box, including DDC active control and passive control in two ways, should give priority to select the active control, because sometimes distribution control circuit is not set control isolating transformer, this passive control contacts may directly access AC220V circuit, causing the interference of other control line. On the other hand, building automatic control system of control of the power to provide by yourself to avoid passing phenomenon. These require the landlord before ordering and distribution control box, makes it easy for manufacturers to processing. But in systems implementation process, often occur due to system hardware interface of the system's ultimate feature deficient, throw in, throw things often happen etc.

4.2.2 software interface

Building automatic control system and refrigeration units, elevators, electrical, lighting control, C-BUS with control device device interface is now essentially the way through the communications protocol. In the above equipment orders in time to the landlord in writing of the interface protocol requirements, so as to avoid the Protocol can not be normal communication between.

4.3 device installation process quality control

Building automatic control system of the front-end device for detecting signal device, on the installation location has strict requirements. Construction process must strictly comply with equipment installation drawings as well as equipment specifications require installation, and focus on reliable grounding device. In the air conditioning control, select the location of the temperature measurement point is particularly important, temperature measurement points should be located in a typical representative of the position. Especially in the lobby and other public sites of temperature adjustment is not old-fashioned installation in air conditioning units of the air supply pipes, but rather to select the representative location points for measuring temperature, so you can truly meet the needs of the owners. Such as the location choice, you can not reach the temperature adjustment, at the same time it has caused a great waste of energy.

5 debugging and acceptance stage quality control

Building automatic control system in the debugging phase, strict construction document checks and on-the-spot checks, checks of qualified construction after debugging framework, following a review of confirmation before you can debug power. Debug process to accurately record the test data, identify problems in a timely manner and to take effective measures to address. Acceptance phase in strict accordance with the specifications and outline requirements for acceptance testing, inspection and acceptance of scientific objective is to ensure that building automatic control system success.

The difficulty of building automation debugging is closed-loop control of PID parameters of connection and air conditioning control parameters.

Debug process often appear on summer and winter and transitional quarter of deepenough. Air conditioning system in the summer, winter and transitional quarter control parameters according to summer and winter and transitional quarter three States of three conditions, and corresponding to the appropriate temperature, humidity or enthalpy etc work environment parameters, if only in the summer, winter and transitional season seasonal changes of actual to simple to understand, often makes the air conditioning system ultimately could not get the desired effect.

In the building automation system debugging, encountered such a situation, air-conditioning control system in operation in accordance with the return air, outdoor air temperature and humidity and set difference of the arguments, keeps changing each air conditioning unit electric regulating valve of the opening, it is often said that "oscillations", eventually forming a hot and cold water pipe flow value is in constant change. In order to resolve the problem, the valve oscillation author site did a few days of testing, combined with the underlying control theory, summing up a solution of the technical approach.

The air conditioning system in operation is the existence of extremely complex dynamical perturbations, external disturbances make air conditioning system originalThere is a balance to be destroyed. Intelligent systems play a role, allowing the system to reestablish a new balance. In the old balance transferred to the new balance through process in automatic control system known as the "transition process". If the "transition process" is the oscillation is convergence, the adjustment will always be in the set value fluctuations of the new balanced homeostasis.

This oscillation is the result of a PID is not good. Therefore, the PID parameter choice becomes the key to solving the problem. Actual comfort air conditioning system is a big inertial system, to control the accuracy requirements are also not particularly high, mainly in the human body feeling comfortable. The higher the precision control, the more easily lead to oscillation system. Adjustment time is too short, too easily lead to excessive vibration, but will result in adjustments to the rebound overshoot. Therefore, in the field of experiments, the authors refer to human engineering point of view, select 5 ° c Fixed deviation value, according to the indoor temperature and humidity and outdoor temperature difference between the nature as set value Select references. Slightly relaxed regulation time requirements, select the appropriate sampling cycle and control functions, allowing the system to achieve a minimum adjustment time, quickly become steady.

Sampling time selection: the selection of sampling time depends on the charged air conditioning units of the response process characteristic curve. Proportional gain P parameters and integral I parameters: these two parameters selection should be based on each air conditioning unit different dynamic characteristics (transfer function) to set in order to obtain a satisfactory transition time is standard.
Through these technical methods to solve the problem of the valve oscillation, now the national customs information center backup center floor control system has been running smoothly for two years.

6 closing

To fully exploit the capabilities of the building automation system, from decision making, design, construction, commissioning and acceptance stage strict control, in particular the project developers with a high sense of responsibility, from a user standpoint, as item made for its own function to configure, and requires the use of units of the engineering and technical personnel promptly added to the project implementation, so as to contribute to the project's implementation and system operation and maintenance, can guarantee the quality of implementation, in order to really bring the efficiency of the building automation system, create a good social and economic benefits.