HACH - Formula for water analysis.
HQ40d Dual-Input Multi-Parameter Digital Meter

The HQ40d Digital Multi-Parameter Meter offers true Plug and Play operation with IntelliCAL pH, conductivity, and dissolved oxygen ( LDO) probes. Plug in any two IntelliCAL probes and get simultaneous measurement, simultaneous readout! " Smart" meters store probe serial numbers, calibration history, user ID, time, date and location of readings.

All data ( up to 500 data points) can be accessed using a simple menu-driven interface with intuitive icons. Transfer GLP/ ISO data effortlessly to a PC or USB flash stick.

Specifications
Power
4 AA batteries; Battery life: > 200 hours
AC/ DC power connection included
Display
Simultaneous readings from two probes
Display Languages: English, French, German, Italian, Spanish ( selectable)
pH Probes: pH, mV, temperature
Conductivity Probes: selected parameter, temperature correction, temperature
LDO Probes: dissolved oxygen, pressure, temperature
Data Memory
500 data points
Data Storage
GLP/ ISO compliant reading data stored with calibration details. Calibration details and check standard readings documented as events in log. Automatically store in " press to read" mode and interval measurement mode. Manually store in " continuous read" mode.
Data Export
Download via USB connection to PC or flash stick. Automatically transfer entire datalog-or as readings are taken.
Temperature Correction/ Compensation
Off, automatic, and manual ( correction is parameter dependent)
Display Lock Function
Continuous measurement or " press to read" mode available with averaging function for LDO measurement.
Automatic pH Buffer Recognition
Choose from 3 sets:
Color-coded: 4, 7, and 10 pH
IUPAC: 1.679, 4.005, 7.000, 10.012
DIN: 1.09, 4.65, 9.23