Data Acquisition and Telemetry Systems (DATS)

The SDI DATS combines a remote data acquisition system with a reliable two way telemetry system. DATS is available in either cellular telephone or dedicated RF telemetry systems.

 

Cellular Version The DATS system includes one or more remote data acquisition units and a master station. Remotes are equipped with cellular telephone/data modems optimized for transmission of digital data through cellular telephone networks. The master station consists of a PC computer, modem, and DATS software. The master station sets the data collection and reporting parameters, collects, displays and stores data from the remotes. The remotes are designed as versatile and reliable data collection and transmission platforms for use where extended operation with low power and minimal servicing are required. The DATS has a flexible design enabling simple addition or deletion of existing features for a customized system for your application.   At scheduled call in times, each remote will power up its serial board and cellular modem and activate its active back plane. A call will be placed and if the communications is acceptable the data will be transferred. Error checking and correction is included. When the data has been transferred the system receives commands from the master station including the next desired call in time and any changes to the sampling plan. Should the data still not be transferred successfully the remote will power down and retry after a five minute waiting period. Up to four additional calls will be made at five minute intervals. Should the data still not be transferred correctly, the data set will remain in the RAM memory buffer and will be added to the data set on the next scheduled call in. The amount of data which can be stored onboard is limited by the amount of additional RAM memory installed. The standard RAM memory will store four days of hourly ADCP data sets along with analog data and housekeeping information.

Remote Units The remote units consist of a Motorola Cellular Telephone Modem, a Motorola HC16 bit based single board computer with a PC bus, an SDI active PC bus back plane, a multiport serial board capable of RS-232, RS-422, and RS-485 communications, an SDI smart power distribution network for power control, optional analog input and signal conditioning, rechargeable battery pack, optional solar charger regulator, optional marine rated solar panels, marine rated cellular antenna, and pressure case for all except the antenna and solar panels. The cellular modem is designed for circuit switched data transmission and includes:   V.22bis compatible Cellular enhanced equalizer to dynamically change to optimize for cellular induced impairments CCITT V4.2 error corrections (MNP4, V.42) CCIT V4.2bis data compression for up to 4:1 data compression (MNP4, V.42) through-put up to 9600 bps Selectable RSSi threshold   The HC16 single board computer can be equipped with up to 1 Mb on-board storage and an additional 1Mb is addressable off board. The DATS operating software is included in EPROM on the board and downloaded to RAM at system initialization or at commandable system restarts from shore. The on board watchdog timer provides additional security from system failure and causes the program to be downloaded and restarted should a failure occur.

Remote self timed devices data acquisition. The DATS system provides periodic data collection from self timed devices such as current meters. The DATS remote system wakes up at a programmed time, turns on power to the serial board, activates its active back plane, and awaits data from the current meter. Once the data has been received from the instrument and the housekeeping functions are complete, the DATS timing for receipt of data is reset based on the most recent data transmission to assure that the systems clock does not drift with respect to the instrument clock. The system then powers down and returns to its sleep mode. In the sleep mode, power consumption is minimized. A low power clock briefly awakens the microprocessor every fifteen seconds to check for systems activity. Data collected is stored in battery backed RAM.

Remote data acquisition direct from analog sensors. The DATS remotes include eight analog channels with four of these channels capable of differential inputs. On- board front end amplifiers can be set for the desired analog gain. Analog data can be collected from sensors for temperature (optional SDI marine temperature probe), pressure, battery voltage (standard on all units), wind speed and direction, humidity, florometers, etc. Typical power consumption of a remote DATS unit is given using two calls per day of ½ hour current meter data with surface temperature, battery voltage, and system status. In these conditions, the DATS uses approximately two A-H per day at 12volts (24w-h). A low power mode is available for applications needing low energy usage. Additional calls or extended calls due to poor cellular conditions can add to power consumption.

Master Station The DATS master station consists of an IBM compatible PC with a high speed modem, a telephone line, and SDI's DATS software. The Master station collects data from each remote, stores the data, calculates the next desired call in time; and communicates the next call in time, and any changes in sampling to the remotes. The master station also receives alarm calls from the remotes and, if requested, makes alarm calls to a designated telephone number. This telephone number can be a pager system with the master capable of leaving an alarm message and remote ID code. Alarms can be sent for no data communications received from the instrument, temperature over or under range, current direction reversal, current speed threshold, buoy off station, low battery voltage, etc. This "Alert to Alarm" call feature provides nearly instantaneous 24 hour notification to shore personnel of an abnormal condition at any of the remotes. The DATS software provides a full screen display with pull down windows for: Set up of communications parameters Operation as a terminal Setting call in times and rates for each remote Setting calibration factors for analog data Adding comments to the system log Viewing collected digital and analog data, and system log Setting alarm timeouts, parameters, and pager numbers Setting display parameters The display includes a window of recent system activity from the system log, status of each remote with its last call-in time and next anticipated call-in time, online help, and critical data parameters reported from each remote.

RF Version The DATS is available with RF Telemetry. In this configuration, data radios replace cellular modems. System operation is nearly identical to the cellular version. Data transmit ranges are typically four to fifteen miles with greater distances available.

 

Specifications                            Spread Spectrum (No license required.)                       Channels 21 channels programmable (905-925MHz) Output Power 725mw Power Requirements 10.5 to 13.8 vDC Data Buffer 20KBytes Packet Size       5-1024 Bytes Range 2-8 miles line-of-sight Options Can be configured as a repeater   (Software configured)            High gain antennas                                                        Dedicated RF Channels   11 channel synthesized (programmable) (403-512MHz) Output Power 2 watts Power requirements      9-16 vDC Range 5-18 miles line-of-sight Options High gain antennas Power Amplifier

      Made in the USA                                  

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