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Pliant Data Acquisition System

Data Sheet (pdf)

PDAS-III Data Loggers

The PDAS-III data loggers feature a built-in menu system which may be accessed directly from your PC, or via modem, or even GOES telecommunications using SAT-HDR high-data-rate transmitter. Firmware upgrades are easily accomplished directly from your PC without having to change any internal parts. The PDAS-III is your solution for a reliable, easy-to-use yet highly capable platform for amassing data as well as provide real-time ALERT capability in the event of flood or drought conditions. No custom software is required for the PC. In fact, the built-in menu system only requires a basic communications package or simply a dumb terminal emulator (eg. Hyperterminal) and is not OS dependent (Windows, QNX, Unix, ).

The PDAS-III, is equipped with the hardware and firmware features listed below and also comes with a number of Telemetry Options. It is also available as a Combo Data Logger (data logger with built-in shaft encoder water level sensor).


  • Two master SDI-12 Serial Digital Interface (20 sensor support) ports labeled Channel A and B
  • RS-232 Programming Port programmable from 300 to 19200 baud
  • Auxiliary Communications Ports for GOES and Modem support.
  • 1 Mbyte Non-Volatile Flash memory Log File providing 32,768 date/time stamped records
  • 1 switched +12VDC port for sensor activation
  • Event & time based data acquisition with a multi-tasking OS
  • Low power consumption through the use of power-down mode
  • Lithium Battery for RTC and 32 kbyte RAM
  • Real Time Clock for date/time stamping of instantaneous, average and minimum/maximum sensor data
  • A +10.5 to 15VDC input for external battery, charger or solar panel
  • Detachable terminal strip for connection of SDI-12 and analog sensors 
And includes the following:
8-channel on-board Analog Input System for monitoring the following maintenance parameters:
  • Primary source voltage,
  • Lithium battery voltage and
  • Internal temperature.
The remaining channels are user-configurable to +/-100mV, 0-1V, 0-2.5V or 0-5V. The A/D provides these inputs with 16-bit resolution.

Outputs of 2.5 & 5V reference. Includes 2 event counters.

Outputs and inputs are provided by means of the detachable terminal strip pictured above.


  • Sensor Log Set-up Table with 16 sensor slots for the attached SDI-12 and analog sensors
  • Individual sensor setup for:
    • User defined sensor Label
    • Sample period setting ( minutes : seconds )
    • Command string for measurement initialization of SDI-12 sensors
    • Linear and Non-Linear (up to 6th order polynomial) conversion equations
    • Instantaneous or averaged log value (record period in hour : minutes)
    • Minimum, maximum log record period (hour : minutes)
    • Sensor sample Start Time ( hour : minutes )
  • 32,768 log records, each 32 bytes in length containing
    • Date Stamp; Time Stamp
    • User-defined Sensor Label
    • and Sensor Data
  • View Data Facility ( selected sensor data written to Host Terminal at a user-defined rate, real-time )
  • User-selectable data formats for log retrieval: Sequential or Tabular with user-defined character delimiter
  • ALARM functions which can:
    • change the logging rate
    • initiate sampling of a sensor
    • provide an emergency dial-out response
  • SDI-12 Transparent Mode ( Manual SDI-12 Communications)
  • Master SDI-12 task engine, auto retries, auto data buffer retrieval & auto command time-outs
  • Data Log Retrieval through standard Comm Packages (eg Procomm) or with any dumb terminal emulator with capture capability


Our PSE shaft encoder is available as a built-in sensor to the PDAS-III as follows:
Part # Description
 /PSE Built-in PSE-SDI shaft encoder (combo data logger) which includes: optical shaft encoder with non-conductive hub, 9V battery backup, EEPROM for address, position & scale settings and AMASSER SDI-12 Compatible Firmware.  The resolution is 1/400th of a revolution. An adaptive sampling technique enables minimal power consumption. Refer to our Price list.
 /PSE/D Built-in PSE-SDI/D (combo data logger).  This is the PSE-SDI shaft encoder described above with optical 8-digit display and operator interface switches and AMASSER SDI-12 Compatible Firmware.  Refer to our Price list.


The following summarizes the telemetry options of the PDAS-III:
Built-in SAT HDR high-data-rate GOES transmitter including comprehensive initialisation and diagnostics routines. Provides ALERT functionality via Random GOES transmissions when user-defined flood and/or drought conditions occur. Refer to our Price list.
Built-in environmental modem. Robust (-40C to +55C), zero power (power-down in idle mode ~1mA) modem which operates on the 12V bus of the logger. External RJ11 connector. Price list.
Built-in environmental VOICE modem. Robust (-40C to +55C), zero power (power-down in idle mode ~1mA) modem which operates on the 12V bus of the logger. External RJ11 connector. Voice option provides remote access to logger in both "data" and "voice" modes. Automatic ALERT dial-out when user-defined flood and/or drought conditions occur. Price list.


Processor - Atmel 89S8252 @ 11.0592 MHz.
Internal RAM - 256 bytes RAM

External Memory
site 1 - Data space: 4 slots of 32 kbytes SRAM (Li bat backup)
site 2 - Code space: 2 slots of 64 kbytes SRAM (Li bat backup)
sites 3&4 - 1 Mbyte non-volatile flash (32768 records)


  • 9 pin DB9S comm connector (RS-232) for direct communication to your PC (cable supplied)
  • Detachable terminal strip for +12V input, SDI-12 ports, analog inputs, outputs and event counters
  • RJ11 for telephone connection
  • MCX and N-type antenna connectors (option /HDR only).
AIS Input
Primary voltage: (0-20V)
Lithium battery voltage (0-5V)
Internal temperature
Four Ext. Voltage Inputs, user-configurable to the following ranges:
  • +/-100mV,
  • 0-1V,
  • 0-2.5V and
  • 0-5V

AIS Output
2.5V and 5V reference

Real Time Clock
Motorola, adjusted to +/- 15ppm per year
Lithium battery backup

Battery Backup
Standard CR2032 3VDC Lithium battery for RTC and RAM backup (date, time, unit no., site description, sensor setup).

Event Counter Input
2 ports supplied with AIS
20 msec closure
Resolution - 16 bit
Rollover or Reset selectable
Pulse or Switch Closure selectable

Power Consumption
< 8 mA w/o comm port connected
< 30 mA w/ comm port connected
Maximum logger current : < 30 mA
Modem: < 120mA when modem is online (<1mA quiescent)
GOES SAT HDR: < 4A when transmitting (1mA quiescent)

Environmental Characteristics
Operating : -40 to +85 C
Storage : -60 to +100C
Humidity : <= 100% non-condensing

Physical Characteristics
Standard models
Height - 120 mm. (4.75 in.)
Width - 200 mm. (8 in.)
Depth - 280 mm. (11 in.)
Mounting brackets with four 8mm holes

Combo models (built-in shaft encoder)
Height - 120 mm. (4.75 in.)
Width - 270 mm. (10.5 in.) incl. shaft
Depth - 280 mm. (11 in.)
Mounting brackets with four 8mm holes

The above information is believed to be true at the time of printing. AMASS Data Technologies Inc. reserves the right to modify specifications without notice. All trademarks are owned by their respective companies.


        © Copyright 2006. AMASS Data Inc 
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