CLIMATE REGULATOR LB-720C

functions: thermometer, hygrometer (humidity meter), controller measurement: temperature, air relative humidity control over the work of a drier/ a humidifier control over the work of a heater/ a cooler signaling the exceed of alarm limits chosen measurement registry

Set functions

• relative humidity and air temperature meter - hytherograph LB-710,
• control - reading panel LB-722C,
• remote control LB-721 used for programming functions of a panel LB-722C.
  

The set is used for measurement and regulation of relative humidity and temperature in the rooms (i.e. warehouses, climate chambers) and signaling of alarm limits exceed.

The reading - control panel LB-722C receives from the attached to it hytherograph LB-710 the relative humidity and temperature measurement results in a chosen point of an object. Basing on it the panel LB-722C through one of 3 transmitter outputs realizes the following configuration functions:

• after exceeding one set (up or low) temperature threshold with a hysteresis +/- 0,5°C it can turn off or on a heating or cooling device,
• after exceeding one set (up or low) relative humidity threshold with a hysteresis +/- 0,5% it can turn off or on a humidifying or drying device,
• after exceeding one of the set thresholds: high or low temperature or humidity it can turn on an alarm signaling,

The panel LB-722C registers in its memory the last 64 relative humidity or temperature results (configuration) in set 1 hour periods of time. The actual measurement results stored in the device's memory cover the last 64 hours and the device settings are shown on two four digit LED screens (digit height 12 mm). The screens can work independently in different work modes. In the basic mode the actual humidity and temperature measurement results are shown. When programming the device one of the screens shows a parameter being set and the other one an adequate description (symbolic parameter marking). A similar situation takes place when scrolling the memory, which contains the measurement results (in such case one of the screens shows – symbolically - time and the other one stored measurement result).

The remote control (programmer) LB-721 is a transmitter used for programming the panel LB-722C settings using an optical link (IR).The programmer LB-721 is a small, portable ("pocket") device, powered from one battery 9 V (6F22). It is equipped with eight key button membrane keyboard, which is very easy to read. Six of those key buttons switch the work mode of the servo's screens and the other two are used for increasing or decreasing a parameter when programming. The following are especially regulated:

• switch on or switch off thresholds of the temperature and humidity executive devices,
• way of controlling the executive devices (switch on/ off after exceeding the set thresholds),
• up and low humidity and temperature alarm thresholds,
• type of the registered measurement(humidity or temperature).

The settings are stored in a panel's nonvolatile memory LB-722C (the values last chosen stay the same after the power supply is switched off).

The special way of programming the device by (using a special remote control) protects the settings from any change. It is impossible to make any unauthorized changes since there are no programming key buttons. The programmer’s work range is approximately1 m.

Set construction

Thermometer - hygrometer LB-710 is an independent device equipped with a capacity relative humidity sensor and a sensor Pt1000 used for temperature measurement. Thermometer – hygrometer LB-710 has a microprocessor, which realizes measurement algorithms by taking into consideration (non-linear) characteristics from both sensors as well as calibration data stored in a nonvolatile memory. The measurement results are transmitted to a panel LB-722C in a digital form with the speed approx. 300 bods and a repetition period approximately 2 s. The current interface used in the device powers the measurement device. This type of solution guarantees simple hytherograph - panel connection, using only two cables. Beside both devices can be placed quite far from each other (distance limited by the connection cable loop resistance - less than 100 ohm). Since the transmission speed is quite slow and current interface standard, high resistance to outside interferences using a cable of any type characterizes the connection. The connection is resistant to changing the cable endings (polarity).

During periodical calibration (confirmation) of the hytherograph LB-710 a two-way digital transmission is used. During calibration a set of coefficients grading the results gets stored in the nonvolatile memory of the hytherograph LB-710M. The regulation elements (potentiometers and trimmers) - that are often the source of problems (thermal instability, noises and clicks, random setting intervention etc.) were eliminated in such way.

Each thermometer - hygrometer (upon a request) can have an individual calibration certificate issued by the LAB-EL Calibration Laboratory or from the Central Army Metrology Center in Zielonka. Thermometer – hygrometer LB-710 received the certification of type RP T 95 77 issued by the President of Central Measurement Office in Warsaw.

The panel LB-722C is equipped with a digital output, which transmits the actual temperature and humidity results with the speed of approximately 300 bps with time intervals approximately 2s. This output works in a standard similar to a hytherograph interface LB-710, what allows on simple creation of a computerized monitoring system of the environmental conditions in many rooms. Such system can include any number of hytherographs LB-710M as well as panels LB-720C.

A simple system with one or two hytherographs or servos can be obtained by connecting them to COM1 / COM2 computer ports through IBM-PC computer using conversion signal systems (current – voltage LB-371) produced by the LAB-EL company. Greater number of system elements can be attached using a concentratorLB-731 produced by the LAB-EL company.

The construction solution used in all devices assure obtaining wide scope of work temperatures (optionally in the M version - up to maximum -40..+70 °C). They also assure high reliability and resistance to interferences. All three devices (LB-710, LB-722C, LB-721) were built basing on the microprocessors especially accustomed to work in such conditions. All plastics used in making the casings resist thermal risks at least in the scope of temperatures -40..+80°C.

Technical data

POWER SUPPLY

Produced by: LAB-EL Laboratory Electronics 68b, Bodycha Str., 02-495 Warsaw tel: (022) 667 71 18, 0601 209656, fax: (022) 867 53 32 e mail: info@label.com.pl home page: http://www.label.com.pl internet meteorological station: http://www.meteo.waw.pl meteorological station on a mobile phone: wap.meteo.waw.pl Last updated: 08.07.2004