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  • Sentinel SMS is a professional system of remote supervision and control for security and automation of remote environment. This two-way RCU (Remote  Control Unit) allows, using a normal phone to make reading of analogical sensors and transducers (e.g. temperature, humidity, pressure, level, etc..) installed in the remote station, and to receive alert by overcome of minimum and /or maximum threshold and alarms from ON-OFF sensors contact ( burglar, fire, flooding, etc…) connected to the digital lines of SENTINEL.

  • It is possible also to control 8 relays in bi-stable mode simply sending SMS or in mono-stable mode at zero cost with a call ring to activate, for example, a motorized gate opener or other electric load requiring short pulse activation. SENTINEL SMS automatically sends a call or, alternatively a confirm SMS message to the caller, if received a valid command by a registered caller, while SMS messages transmitted by unregistered callers are ignored and deleted without execution. SMS containing a valid command is executed and then automatically deleted from the SIM-card.

  • SENTINEL SMS can also inplement a local embedded ON-OFF  automatic control, enabling the appropriate user parameters and setting the minimum and maximum threshold levels so the related relays are controlled and activated as function of temperature and voltage level. You can preset up to 8 alarms for minimum and maximum set-point, both voltage and temperatures. There are also 8 digital input lines TTL level, whose change of state ( one or more inputs) let send an SMS alert reading the state of all inputs.

  • The analogical and digital alarm management is very complete, allowing a precise analysis of environmental conditions remotely controlled. The system generates an alarm cycle when the threshold is exceeded, i.e. temperature and/or voltage and the current alarm status is stored on the EEPROM; when the sensor reading returns to the normal level, namely within the threshold, is generated a second cycle alerts (SMS or call) to indicate that value of the input (analogical and/or digital) returned to normal level.

  • The digital alarms are trigged by opening one or more input lines that are normally closed to ground; It is available a pre-alarm delay, (0 to 255 s) within which there is no alarm generation, but it is only displayed the warning for opened line and elapsed time.

  • The typical  application fields of SENTINEL are: remote activation of heating systems and boilers, air conditioning systems, lighting, irrigation, burglar alarms, etc.. and remote opening of doors and gates, as well as control of remote environments, with the possibility of receiving alarms generated by environmental remote sensors and reading sensors and transducers.

  • SENTINEL SMS is equipped with a 4 x 20 LCD backlighted, for the detailed view of all phases of operation and the messages received by the modem, allows it to read 8 analogical input voltage (0 – 3 V) with a resolution of 10 bits, useful for the acquisition from remote sensors and transducers, for example, temperature, liquid level, pressure, etc.


  • SENTINEL SMS can operate as standalone ON-OFF automatic regulator: enabling the appropriate user parameters, you can implement a controller that controls up to 8 relays, as a function of temperature and/or voltage input, prefixing the minimum and maximum set-point.

  • To make a better control function and avoid oscillations around the threshold value (set point), there are two correction factors hysteresis, low and high, set by the user, the default factory setting is set at 1% (IST-low = 0.95, IST-high = 1.05). It is also possible, by setting the appropriate parameters, enable the activation of the relay according to the state of digital lines, and then repeat the alarm on a line corresponding relay (eg open line 1 -> 1 relay activated) All phases of entry and exit from the analogical and digital alarms are indicated on the LCD. The enabling of the alarms are made by writing the appropriate parameters in the relative locations of EEPROM.

Overall Specifications

  • GSM Dual Band industry standard MODEM 900-1800 MHz with SMA Antenna

  • Bi-directional Controller System by receiving and sending SMS

  • Based on Atmel AT89C51AC3 Microcontroller  

  • System Memory: 64 kB Flash, 2,4 kB RAM, 2 kB EEPROM

  • SIM Card standard reader built into GSM MODEM board

  • 8 Relays Outputs with SPDT 10 A 250 V contacts and optical-couplers

  • 8 Analogical Inputs with 10 bit resolution in the 0-3 V range

  • 8 Digital TTL level Inputs with reading of state an alarm trigger

  • 8 Status LED for relays control

  • Bistable command via SMS to control each of 8 relays

  • Monostable command no cost (automatic rejection)

  • Up to 250 registered users, 9 of which registered as Admin for alarm receiving

  • Automatic Answer by ring or sending SMS to registered caller

  • Compiled Firmware Flash resident upgradable by PC via RS232C

  • Local Automatic Regulation by analogical thresholds min, max and ON-OFF control

  • LCD Module 4 lines x 20 characters with LED backlight

  • Hexadecimal Keyboard for user setup and commands (future expansions)

  • RS-232C Serial Interface for parameters setup and upgrade download

  • Standard IDC 2,54 mm connectors for flat cable and screw terminals

  • Power: switching 220 Vac/13.8 VDC with line transformer and backup battery

  • Dimensions: Metal enclosure 225 x 215 x 80 mm

  • Weight: 2,7 kg with 12V 1,2Ah Battery

  • User Manual and software utilities for download on CDROM

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