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Low cost server environment monitor Hx531R

Also known as: remote server environment monitoring, computer room monitor, data center thermometer, temperature humidity IP sensor, computer room temperature alert.

../rack monitor - front view - larger photo

Rack monitor - front view

rack monitor - rear view - larger photo

Rack monitor - rear view

server environment monitor

Server monitoring system is designed for 19-inch rack mounting, the height is one rack unit - 1U. Rack-mount monitors are very convenient for cabinets.
The Hx531R monitor can be fitted into a rack "zero U" because of its thin design.
It can fit behind other equipment taking up space that is otherwise unusable.
Model H4531R is prepared for connection of external Pt1000 temperature probe and models H3531R, H7534R are equipped with 1 meter temperature + humidity probe. Unit also contains three binary inputs for detection of two-state events - e.g. power presence, water, smoke, airflow, glass break detection, door contact.
Rack unit provides 5Vdc and 12dc power supply for external all sensors and detectors.
Large dual line LCD for simultaneous display of temperature, humidity is an advantage. Parameters are easy adjustable from transmitter keyboard or from the computer.
State-of-the-art capacitive polymer sensor ensures excellent calibration long term stability, inertia against water and condensation.
Environmental monitor is equipped with two relay outputs for alarm indication or control of external devices. Each relay can be assigned to any measured value.


Easy creation of online data acquisition system from several rack monitors by using new low cost database software Comet DBS Sensor Monitor - see also Accessories.

online monitoring

APPLICATIONS - online monitoring of temperature, humidity, power, flood, smoke, airflow, room entry at:

Modbus TCP: Modbus TCP protocol enables to read measured values and binary input states, set alarm limits, adjust the probe.
Telnet: Port 9999 enables to set alarm limits (lower, upper limits, hysteresis for measured values and time delay), e-mail addresses, SNMP addresses, probe description, refresh of www pages (10s to 65535s), set storing interval to history (10s to 65535s), enable each communication channel. Capacity of the history memory is 100 sets of temperature, humidity, pressure + computed values. Password protection of this port is enabled. Automatic IP address assignment from DHCP server is also enabled.
WWW pages: User selectable design of www pages enabling to display curve of measurement history and binary input states. User can design the look of www pages and temperature, humidity, pressure + computed values history.

Temperature, humidity, pressure in Roznov p.R., Czech Republic
from online www internet sensor T7511

SNMP: It is possible to read actual values, alarm limits and binary input states. In case of alarm creation warning message (trap) is sent to addresses defined by the user (maximum three addresses).
SOAP: Online transmitter enables to send actual measured data in the format of SOAP message to selected web server in preset interval 10-65535 s.
Online transmitter enables to monitor measured values and binary input states. In case of exceeding of adjusted limits warning message can be sent to specified addresses.
There are the following options of alarm indication:
E-mail: In case of alarm creation warning e-mail message is sent to addresses defined by the user (maximum three addresses) or via e-mail to SMS message. Basic SMTP autentization is supported.
SNMP: In case of exceeding of adjusted temperature, humidity, pressure + computed value limits or binary input states alarm is activated and warning trap is sent to user specified IP addresses (maximum 3 addresses).
WWW pages: In case of exceeding of adjusted temperature, humidity, pressure + computed value limits or binary input states active alarm is displayed on www page.
syslog: Online transmitter enables to send text messages to selected syslog server after different events appear. E.g. after transmitter restart, alarm activation, communication error with SNTP, after firmware change, after alarm termination, after communication error with SOAP server.
Synchronizing of time and record to www table and measured values history is enabled by SNTP via Internet.
Maximum switching voltage, current, power of relay output: 50V, 2A, 60VA
Operating relative humidity range: 0 to 100%
Accuracy of relative humidity measurement: ±2.5% relative humidity from 5 to 95% at 23°C
Temperature measurement accuracy: ±0.4°C
Available temperature units: degrees Celsius, Fahrenheit
Accuracy and range of barometric pressure output: ± 1.3hPa at 23°C
range: 600 to 1100hPa
Temperature operating range of case with electronics: -30 to +80°C
Temperature operating range of LCD display: readable to operating temperature +70°C, it is recommended to switch OFF the LCD over +70°C
Range of RH sensor temperature compensation: -30 to +105°C
Signal for binary inputs: from voltage-less contact, open collector or two-state voltage signal.
Inputs are not galvanically isolated.
Minimum pulse length at binary input: 500 ms (shorter pulse may not be detected)
Voltage at open contact: 3.3 V
Low voltage level: 0 to +0.2 V
High voltage level: +3.0 to +30V
Filtering ability of sensor cover: 0.025mm - filter with stainless steel mesh
Protection: IP30
LAN connection: RJ-45 connector
Power: 12 Vdc, maximum consumption 250mA.
For power over Ethernet any PoE splitter is necessary e.g. DWL-P50 from D-Link company
Power connector: co-axial, diameter 5.5 x 2.1 mm
Dimensions of the case: 483 x 44 x 45 mm (W x H x D), one rack unit 1U
Weight: approximately 1100 g
Warranty: two years
ModelMeasured valueMaximum measuring rangesDescription


3 bin. inputs
-200 to +600°C Temperature transducer for
RTD Pt1000probes
(not included).
Accuracy of the input without probe +/-0,2°C


3 bin. inputs
-30 to +105°C* including probe cable

relative humidity 0 to 100%
Included T+RH probe with 1m cable. Cable lengths 2m or 4m available optionally.

Humidity values available also as dew-point temperature, absolute humidity, specific humidity, mixing ratio, specific enthalpy.


atmospheric pressure+
3 bin. inputs
-30 to +105°C* including probe cable

relative humidity 0 to 100%
atmospheric pressure: 600 to 1100hPa
accuracy: +/-1,3hPa at 23°C
Included T+RH probe with 1m cable. Cable lengths 2m or 4m available optionally.

Humidity values available also as dew-point temperature, absolute humidity, specific humidity, mixing ratio, specific enthalpy.
Reading and pressure output in these units:
hPa, kPa, mbar, mmHg, inHg, inH2O, PSI, oz/in^2.

Barometer enables to measure sea level pressure by setting of correction to altitude above sea level.

Ethernet sensor - manual in pdfManual in pdf

* Relative humidity at temperature over +85°C is limited in accordance with the graph. Near plastic case with electronics and probe cable maximum temperature is +80°C.

Working range of Ethernet sensor

Figure: Working range of Ethernet sensor

Included accessory:

Traceable calibration certificate from the manufacturer, instruction manual. Calibration certificate with declared metrological traceability of etalons is based on requirements of EN ISO/IEC 17025 standard.
Example of calibration certificate.

Set of four rack mounting screws is also included.

TSensor - freeware for online configuring of the transmitter is ready to download.

SensorReader - freeware for online logging values from one transmitter to a PC disk file is ready to download. Program enables to alarm acoustically the PC user if adjusted alarm limits are exceeded. Recorded values in CSV format are easy to process in e.g. Excel. Program can be started several times on a computer at the same time to monitor values from several transmitters.

For acquiring values from several transmitters, also third party software is possible to use. Tested functionality is with programs:
LabVIEW from National Instruments.

TIRS.NET - transmitters are also directly supported by program TIRS.NET from Coral s.r.o. company. Please download demo enabling full work with transmitters.

Database Sensor Monitor DBS Database program DBS Sensor Monitor for online data acquisition and analysis from Comet sensors. It contains all necessary components for monitoring of sensors, including one licence of DBV Database Viewer.

More information on online data acquisition.
Power detector SP008 AC voltage presence sensor, connectable to binary Hx531 inputs.
Flood detector LD12 Water leakage detector, two-state output, connectable to binary Hx531R inputs.
With 3 meters cable.
Powered from Hx531R 12Vdc output.
Rack monitoring smoke sensor SD280 Optical smoke detector, relay output, connectable to binary Hx531 inputs, powered from Hx531R 12Vdc output.
The SD280 detector combines an optical smoke sensor with a heat sensor.
Both sensors have their outgoing signals processed digitally, resulting in higher false alarm immunity.
motion detector JS20 P.I.R. motion detector is for interior protection. It detects object movement having a human body temperature. The JS-20 distinguishes itself with excellent RF immunity. The signal from the sensor is electronically analyzed. This ensures that the detector provides excellent sensitivity and false alarms are basically eliminated. The detection analysis rate can be adjusted to increase its immunity if the JS20 is installed in a problem location. It can be mounted on a flat wall or in a corner. Connectable to binary Hx531R inputs, powered from Hx531R 12Vdc output.
Rack monitoring door contact SA200A Magnetic door contact, connectable to binary Hx531 inputs, without cable.
Rack monitoring door contact SA200A-2
Magnetic door contact, connectable to binary Hx531 inputs with cable lengths 2, 5, 10, 20, 30 meters.
probe holder - larger photo probe holder - larger photo MP047 Universal holder for probes for easy mounting to rack 19"
(probes not included)
Larger photo of humidity transmitter flange PP90 right-angled stain-less steel flange for wall mounting.
Tool for easy transmitter connection - larger photo SP006 Tool for easy wire connection to terminals.
Larger photo of adapter for hygrometer A1515 ac/dc adapter 230V-50Hz/12Vdc.
Larger photo of adapter for hygrometer DWLP50 DWL-P50 Power over Ethernet (PoE) adapter from company D-Link.
The adapter is supposed to be connected to Ethernet switch supporting PoE.
humidity calibration accessory for calibration and adjustment of humidity by the user.

Software and firmware for transmitters.

You can downlaod configuration programs and updated firmware from page Download - transmitters and transducers.

Visit also Comet:

Rack monitoring Wall mount environmental monitors Rack monitoring Low cost Ethernet sensors
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