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GP-HR Technical Information

GP-HR 6 Pin Connector :
  • Probes are connected to the  GP-HR Datalogger via a 6 pin Switchcraft Plug.
  • Switchcraft is a company name.
  • The logger has a female socket.
  • The probe or probes require a 6 pin Male InLine Plug, Switchcraft Part Number EN3C6M
  • These are available from Trutrack as part number EN3C6M
  • They are also available from Farnell as part number 727-034
Identifying the Pins :
  • There is a small  index mark (Dot)  next to  Pin 1 on both Plugs and Sockets.
  • You may need a magnifying glass to see this.
  • Looking at the rear (solder end) of the 6 pin Male InLine Plug
    • With the Key way  to the top
    • Pin 1 is Top Left
    • Pin 2, 3, 4, and 5 are the next pins in an anticlockwise direction
    • So Pin 3 is at the Bottom and pin 5 is at the Top Right
    • Pin 6 is in the middle
pinout6.gif (2129 bytes) View from Front of Socket or Rear of Plug
Pin Functions :
Pin 1 Supply +3.6 volts see note
Pin 2 First Analog Input
Pin 3 Second Analog Input
Pin 4 Third Analog Input
Pin 5 Fast Pulse Input
Pin 6 Common Ground 
Note: The Supply voltage is derived directly from the logger battery and will therefore decrease during the life of the battery. The supply voltage is switched ON 10mSec before data acquisition and is switched OFF again after data acquisition.
Electrical Characteristics of the Analog Inputs:
  • The three analog channels have identical characteristics.
  • Each channel can operate in two modes, Absolute and Ratiometric.
  • The mode of operation is determined by the probe type selected for that channel.
  • The probe type is selected using the Channel and Probe Setup Tab of the Logger Control Screen in the Omnilog Software.
  • Using this software, a different Probe can be selected for each Channel.
  • Temperature (Thermister) , Pressure and Humidity probes are typically Ratiometric.
  • Voltage and current inputs are Absolute.
Maximum readable input voltage in Ratiometric mode 3.6Volts Nominal see note
Maximum readable input voltage in Absolute mode 2.048Volts
Maximum voltage input without damaging logger 5 Volts
Maximum current to be drawn by the combination of all three probes 5mA
Input Leakage Current 0.1uA
Note: The maximum readable voltage in ratiometric mode should be derived from the logger supply (Pin 1) and will therefore decrease over the life of the battery to a minimum of 2.7 Volts.
Electrical Characteristics of the Fast Pulse Input:
  • The fast pulse input can be used in two modes. Counter or Frequency
  • Counter mode is used for  functions such as rainfall.
  • Frequency Mode is used  for wind speed or flow sensors.
  • The mode of operation is determined by the probe type selected for that channel.
  • The probe type is selected using the Channel and Probe Setup Tab of the Logger Control Screen in the Omnilog Software.
Maximum Count Per Logging Period 65535
Maximum Frequency 64kHz
Preferred Switch Input Type Normally Open
Preferred Digital Input Type Normally High
Minimum High Period 1uSec
Mininum Low Period 1uSec
Input Impedence 470kOhm
Prefered voltage input  3.6 Volts
Maximum voltage input  5.0 Volts
Note: This input has been primarily designed for switch connection ( eg Tipping Bucket Rain Gauge) It has an internal 470kohm resister pull-up to the internal 3.6 Volt battery. Any device that holds this input low will cause a constant battery draw of 7.7uA that will  shorten the battery life by up to 3 months.

Warning - Due to the fast response time of this input, debounce will normally be required for switch inputs.

Some Typical Configurations :