GP-HR - General Purpose Data Logger:

Product Specifications:

Download Datasheet

GP-HR with mA3+P-PS probe set

GP-HR shown with mA3+P-PS probe set (3x 4~20mA inputs + 1x Pulse input)

The GP-HR is a high resolution (12 bit) multi purpose data logger that can be configured to accept inputs from a wide variety of sources including:

  • 4~20mA Probes
  • Voltage (DC)
  • Current (DC)
  • Temperature Probes
  • Pressure Probes
  • Flow Sensors
  • Frequency
  • Light Sensors
  • Leaf Wetness Sensor
  • Soil Water Tension Probes
  • Wind Speed Probes
  • Wind Direction Sensors
  • Tipping Bucket Rain Gauges
  • Solar Radiation Sensors
The GP-HR also has an internal temperature sensor for convenient logging of ambient temperature if desired.

The GP-HR (mark 4) features a MASSIVE storage capacity of over 1,000,000 8bit samples; or over 500,000 12bit samples, as well as a user replaceable battery!

Ordering Information:

Order code:


GP-HR General Purpose data logger

Standard Probe Sets; Other types available - Contact Intech Instruments:

mA1-PS One 4~20mA or 0~20mA input
mA3+P-PS Three 4~20mA or 0~20mA inputs c/w One Pulse input
##VD3-PS Three DC voltage inputs. ## = Specify voltage up to 32Vdc.
(Maximum voltage input for the GP-HR is 32Vdc (32VD3-PS) - for
voltages >32Vdc use an intermediary transmitter like the PI-D)
L-PS Light Energy
Pt3-PS Three Pt1000 Temperature Probes, range -50~130ºC
Note: GP-HR maximum Pt1000 temperature range is -100~400ºC
P###-HR-PS Pressure Probe - available ranges are: P100-HR-PS = -15~100psi,
P250-HR-PS = -15~250psi, P500-HR-PS = -15~500psi
Flow-mA2-PS Coil or open collector plus two 4~20mA inputs
ACM-mA2-PS Flow metering off the pump run contact plus two 4~20mA inputs

Download options:

OmniLog Software (used with all TruTrack data loggers):
OmniLog Installation CD and USB download cable Kit
OmniLog Installation CD and RS232 download cable Kit

Spare download cable:
HR Series USB download cable
HR Series RS232 download cable

Note: GP-HR inputs are individually configurable using OmniLog. Each input requires conditioning using a 'Probe Set'.

GP-HR application links:

4~20mA Rainfall
Voltage Light / Solar
Pressure Counter, Flow and Frequency
Resistance Rotary Distance
Temperature Switch
* Thermocouple * (see below) Leaf Wetness

Jump to Probe sets available for the GP-HR >

* Logging Thermocouple inputs with the GP-HR:

A lot of people say thermocouple to mean temperature probes, where as if the temperature range they are measuring is between -50 and +200 degrees C, then Pt1000 is more accurate and cheaper to implement than thermocouple. Thermocouples are ideal for high temperature ranges.

The only way that the GP-HR can accept a thermocouple signal is via an intermediary transmitter like the XU Series with an output signal of 4~20mA. An mA#-PS adaptor cable for each input from the XU Series transmitter(s) to the GP-HR is also required (with the correct number of inputs [1-3]).

If you wish to log only 1 thermocouple input then there are 2 possible options:


External Sensor Connector:

6 pin Switchcraft Plug ( EN3C6M )
1 Switched Reference voltage
2 First Analogue Input
3 Second Analogue Input
4 Third Analogue Input
5 Fast Pulse Input
6 Common Ground
GP-HR pinout View from Front of Socket or Rear of Plug

Three Analogue Channels:

To log any combination of:
Temperature Wind Direction
Humidity Soil Moisture Tension
Pressure Leaf Wetness
Light Voltage (DC)
Solar Energy Current (DC)

The three analogue 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 3.3 Volts
Maximum readable input voltage in Absolute mode 2.048 Volts
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

One Fast Pulse Digital Channel:

To log:
Wind speed
Counter (up to 65535)
Frequency (up to 60 kHz)

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 with logging period set to 1sec 60kHz
Preferred Switch Input Type Normally Open
Preferred Digital Input Type Normally High
Minimum High Period 1uSec
Minimum Low Period 1uSec
Input Impedence 470 kOhm
Preferred voltage input 3.6 Volts
Maximum voltage input 5.0 Volts

Internal Temperature:

Sensor Type Thermister
Linear accuracy over range ±0.3ºC (0ºC to 70ºC)
Repeatability ±0.1ºC
Long term stability ±0.1ºC


Working Temperature -30ºC to +70ºC
Storage Temperature -30ºC to +70ºC
Sampling Rate
1 second minimum
10 hours maximum
in 1 second intervals
Storage capacity
1,044,480 8 bit samples; 522,240 12bit samples
Over 600 days logging 3 Hi Resolution Channels every 5 minutes
Two independent Alarms
Triggered on any combination of six user configurable Alarm Conditions
Both alarms can be configured to send SMS messages
Alarms can be visually checked using the OmniLog Software
Start modes
Start immediately
Start on date/time
Stop modes
Stop when memory is full
Stop on date/time
Loop around (continues logging)
Logging Modes
Each channel can be set to log any combination of:
  • Point readings
  • Average reading
  • Maximum reading
  • Minimum reading
Warning: When using the Average, Maximum or Minimum reading(s), the logger reads the attached sensor(s) every second. This will reduce battery life.
1 to 5 year battery life depending on usage as above
User Replaceable (Instructions Required)
One 7.2Volt lithium pack (Available from Intech Instruments)
Using the logger in temperatures below -5°C (23°F) will reduce battery life
The data is retained in the case of battery failure
Battery Status Monitor in OmniLog Software
Download Time 9 minutes, 30 seconds for Full Logger
Download cable DLC3USB [USB] or DLC3 [RS232]
Case material 304 Stainless tube
Screw on end cap Plated brass
Weight 150g
Size 20mm diameter X 180mm long

Standard Probe Sets; Other combinations available - Contact Intech Instruments:

1 External Temperature
2 External Temperature
3 External Temperature
Humidity & Temperature Probe
Humidity & Temperature Probe with additional Temperature Probe
Pressure & Temperature Probe
Pressure & Temperature Probe with additional Temperature Probe
Light / Solar Energy Probe
Light / Solar Energy Probe with additional Temperature Probe
Rain Gauge Adaptor
Rain Gauge Adaptor with additional Temperature Probe
Wind Speed Anemometer
Wind Speed Anemometer with Temperature Probe
Leaf Wetness Probe
Leaf Wetness Probe with additional Temperature Probe
3 input 4 to 20mA adaptor
More information on available probe sets for the GP-HR is available here.

GP-HR with Pt3-PS probe set

GP-HR shown with Pt3-PS probe set (3x Pt1000 temperature probes)

OmniLog Flow Wizard GP-HR Application Notes:

Download Flow Wizard Application Notes