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Laboratory Electronics

Microclimate control in the plant growing chambers using a regulator LB-600

EXAMPLE APPLICATION
  • control functions: maintaining set temperature, humidity and illumination depending on time 
  • measurement: temperature and humidity
  • cooperation with a computer system  
  • interface RS-232C and S300
  • other: real time clock
LB-600

TASK DESCRIPTION AND APPLICATION

Basic task of the whole system is maintaining the optimal parameters in the artificial farming chambers needed for growth of chosen plants. The control parameters covered include: humidity, temperature and illumination.

Physical device configuration of a regulator LB-600 is the following:
  • 2 packages of binary, transmitter inputs/outputs, 
  • a package of series transmission with an interface RS-485 and S300.

The measurements realized are through the hytherographs LB-710 connected to two measurement channels. The temperature and humidity measurements in two chambers are realized through the hytherographs LB-710 connected to two measurement channels S300.

Schemat blokowy
Picture 1. Functional block blueprint of controlling the pyranometers
The regulator’s internal structure displayed below realizes the following functions:

Humidity regulation is realized by a functor 71 in chamber 1 and by a functor 73 in chamber 2 through binary-transmitter outputs that switch on a humidifier and a dehumidifier, adequately from the outputs A1 and A2 in a package 3, in the chamber 1 as well as A1 and A2 to a package 2, in the chamber 2. Three-joint regulation 3P was used in the system (for the heating and cooling systems). Specific feature of the regulation is the usage of the functors as 39, 3A and 51 as well as 3D, 3E and 53, as the selectors of a set value switched over by a logical status of the functors 31 and 32 adequately. Switching over the set values is synchronized with starting the timers that switch on the lighting.

Temperature regulation is realized by a functor 72 in chamber 1 and by a functor 74 in chamber 2 through the binary-transmitter outputs switching on a heater and a cooler, adequately from the output A4 and A3 on package 3, in chamber 1, as well as A4 and A3 on package 2, in chamber 2. Three-joint regulation 3P was used in the system (for the heating and cooling systems). Specific feature of the regulation is the usage of the functors as 3B, 3C and 52 as well as 3F, 43 and 54, as the selectors of a set value switched over by a logical status of the functors 31 and 32 adequately. Switching over the set values is synchronized with starting the timers that switch on the lighting.

The timers switching on the lighting and switching over the set values of humidity and temperature are started by a signal from the Binary Statuses Registry (RSB). The lighting in chamber 1 is switched on with a delay set in a block 41 in relation to a start time (RSB=407, it is a clock alarm 1). The lighting in chamber 2 is switched on with a delay set in a block 42 in relation to a start time (RSB=408, it is a clock alarm 1). 

Additionally, also the ventilators work in the system, one in each one of the chambers, and are switched on through the transmitter outputs A5 from the package 2 for the chamber 1 and A5 from a package 3 for chamber 2. The ventilators are switched on from the generators 37 and 38, where the ventilators’ work time was programmed T1 = 900s = 15 minutes along with a break time T2= 7200s = 2 hours is programmed. 

Four chambers are served in a plant growing station, from two identical control systems. Both regulators (serving all the chambers) are connected through a converter RS232/RS485 to a computer, where LBX program registers data and allows on changing the parameter values in a control process.

Struktura
Picture 2. Internal structure of a controller operating the climate parameters
The regulator with a temperature and humidity sensor, adequately to an order can have an individual calibration certificate of temperature measurement path from the Institute of Power Engineering in Warsaw or from the Calibration Laboratory LAB-EL. 

TECHNICAL DATA

SYSTEM PARAMETERS
Measurement / control
Scope of measurement
Comments
Temperature measurement
-40..+60°C
Chosen scope – possible scope exceeds the scope of applications in farming.
Humidity measurement
10..95% RH Possible to be extended up to 0...100%
Humidifiers and driers controlled in a three-joint matter.
Random
Through selected for a device transmitters and contractors.
Heaters and coolers controlled in a three-joint matter.
Random Through selected for the devices transmitters and contractors.
The ventilators controlled in a timer function (real time clock).
Random Through selected for a device transmitters and contractors.
The lighting controlled in a timer function (real time clock).
Random Through selected for a device transmitters and contractors.
Detailed technical data and recommended work conditions can be found on a web page of the hytherograph LB-710 and the regulator LB-600.
See also
See also
Regulator LB-600 Regulator LB-600
The regulator LB-600 is a universal, programmable, digital regulator designed for measurement systems, control and regulator of different technological processes.
Informacje o LB-600 Informacje o LB-600
Universal microprocessor regulator LB-600 was designed with taking under consideration all requirements put to similar devices used in the industrial automation.
Przechowalnia Przechowalnia
An irrigation control system is used for maintaining a set level of moisture in the soil on the cultivation ...
lb-600-pyranometr-02 lb-600-pyranometr-02
Controling the location of pyranometers using a regulatorLB-600; essential objective of the whole system is data collection concerning solar radiation in time function; measurement: light intensity and additional meteorological measurements,