HUMIDITY AND TEMPERATURE REGULATOR LB-474C

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two channel regulator two channel thermometer, psychrometer big, easy to read display interface RS-232C and S300 controlling 4 devices exceed signaling

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DESCRIPTION

Regulator LB-474C is an integrated device, which realizes temperature measurement function at two points and control over the executive devices allowing on maintaining specific climate parameters. The device can be used as a meter and a regulator of temperature and humidity, after being attached to a psychrometer in a place provided for the temperature probes. A controller allows on defining two regulation trajectories with two executive devices for each trajectory that are switched on of off by LB-474C in specified by a user conditions.

The device allows on defining the threshold values of the measured values and by using an alarm output signals the situations, where a value exceeds an acceptable interval. 

The regulator has a big, easy to read LED display (digit height 25mm and 10mm), which presents a measured temperature value (on a big display) and another temperature or humidity (on a smaller display). The measurement results are available to be read through a series port RS-232C as well as through a port S300 that works as a digital current loop. 

The device performs measurement of two temperatures using the outside sensors with the platinum thermo resistors Pt-1000 (or optionally Pt-100). Applying of the platinum thermo resistors assures high measurement accuracy and constancy of thermometer characteristics. The outside temperature sensors are made in the casings adjusted in construction to the individual requirements. Various types of sensor casings allow on measurement of different media in various scopes of temperature. Two thermometers can also make a psychrometer (working based on a principle of a dry and wet bulb thermometer), what allows on independent measurement and regulation of air temperature and humidity. The temperature sensors are attached to the regulator using clamps.

The temperature measurement trajectory is calibrated by a producer and the calibration data is stored in a panel in a digital form. The controller does not have any mechanical calibration elements (i.e. potentiometers). The calibration of the device is performed by sending calibration data obtained in the model climate conditions through a digital interface to the non-volatile memory of the device. It guarantees comfort and high calibration accuracy as well as stability of the device's meteorological parameters in time.

The regulator LB-474 has five control outputs with outputs with the transistor keys, assigned for controlling the outside transmitters (i.e. in a form of an outside unit of transmitters LB-475).

The device is designed to be used in the stationary conditions and its casing has clamps allowing on assembly on a standard bus rail TS35. The device is powered from the energy network 230V. 

The regulator with the temperature sensors, adequately to an order, can have an individual calibration certificate of temperature and humidity measurement trajectory from the LAB-EL Calibration Laboratory. 

REGULATION

The device realizes threshold regulation in two independent trajectories. For each trajectory a controlled parameter can be defined (one out of two temperatures or humidity) and a way of the outputs control.

Rys. 1	Rys. 2	Rys. 3

The simplest control mode is based on controlling one executive device, which is switched on when a measured parameter drops below a certain threshold value and switched off if it goes beyond an accepted value. Picture no. 1 shows an example of temperature regulation using a heater as an executive device: heating is switched on below temperature SP+h1 and switched off above temperature SP+h0. It is possible to reverse the control logic and attach a cooling device.

The second control mode allows on two stage control over one executive device or two separate devices of the same character. Example on picture no. 2 illustrates a situation of controlling an object’s temperature in this more. Below temperature SP+H1 both degrees of power are switched on and work until temperature reaches a level SP+H0, after that heating power is reduced. A total switch off is performed after reaching SP+h0. After temperature drops to a level SP+h1 one degree is switched on and if temperature still drops then the other one is still switched on with SP+H1. Similarly like for the previous mode it is possible to reverse the control logic and supervise i.e. two cooling units.

The third mode allows on controlling a parameter using two executive devices, where one increases and the other one diminishes value of the measured parameter. Picture no. 3 shows an example of controlling temperature using the heating and cooling devices. A user defines switch on and off thresholds separately for each one of the devices.

TECHNICAL DATA

MEASUREMENT READINGS
Parameter	Scope of reading	Resolution displayed
Temperature	-99,9..+99,9°C	0,1°C
	+100..+259°C	1°C
Humidity	5..99,9%	0.1%

MEASUREMENT UNCERTAINTY
Parameter	Scope of reading	Uncertainty
Temperature	-40..150°C	0,1°C +/- last digit
	-99,9..+259°C	1°C +/- last digit
Humidity	0..15	2% +/- last digit
	15..50%	1,5% +/- last digit
	50..99,9%	1% +/- last digit

POWER SUPPLY, CONTROL OUTPUT
network power supply	230V 50 Hz
energy consumption	5 VA
control outputs fan-out (open collector LB-474C)	40V, 500 mA, DC
control outputs fan-out (a block of transmitters LB-475)	230V, 6A, AC/DC
type of fan-out	resistance or a transmitter coil

SCOPE OF WORK TEMPERATURES
Device	Scope	Comments
Regulator LB-474C	0..+50°C
Temperature sensor	-60..+90°C	basic scope, limited additionally by a temperature sensor's construction
	-150..+259°C	extended scope, limited additionally by a temperature sensor's construction

RECOMMENDED CONSTANT WORK CONDITIONS LB-472
Scope of temperatures	10..40°C
Scope of humidity	20..80%
Level of environment corrosion aggressiveness according to PN-71/H-04651	B
Class of resistance according to DIN40050	IP40

*) - Going beyond recommended constant work conditions (i.e. when installing a device in the open space) requires applying additional safety means for the device's electronic parts protecting from water out dropping inside the device (application of an additional outside casing).

INTERFACE I - voltage

Series RS232C, 3 lines (RxD, TxD, GND), transmission parameters: 9600 bps, 8 bits of information, without evenness control, 1 stop bit.

INTERFACE FUNCTIONS I

Possibility of reading the measurement results and storing the device's calibration results in its non-volatile memory.

INTERFACE II - current

Series so called digital current loop, 1 line TXD (TXD line active status complies with 25 mA current, in the rest stage 15 mA), transmission parameters time in accordance with RS232C: 300 bps, 7 bits of information, without evenness control, 1 stop bit.

INTERFACE FUNCTIONS  II

Possibility of sending the measurement results automatically to long distances in big measurement systems (i.e. to a multi-sensor climate supervision system - see LB-473). Output with a galvanic isolation.

OVERALL DIMENSIONS

Panel casing (to be hanged on a rail TS35) overall dimensions: 158 x 90 x 58 mm.

Attention: The device should be installed inside an additional outside casing, i.e. wall switch gear. Climate category of the additional outside casing has to be adjusted to the conditions dominating in the place of installation. No cables are supplied with the device (including a power supply cable) as an installation component for only an authorized person.