ROTRONIC HygroLog HL-NT - Manual (Page 25)

IN-E-HL-NT-V2_12
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroLog HL-NT data logger:
instruction manual Instruction Manual
Document Type
Page 25 of 48
Document title
© 2009-2012; Rotronic AG IN-E-HL-NT-V2_12
3.3 Docking station inputs
Depending on the model of docking station, the signals from up to 4 additional probes can be
processed by the HygroLog HL-NT.
3.3.1 HygroClip 2 probes
By default inputs 4, 5, 7 and 7 of docking stations HL-DS-U1, HL-DS-U2, HL-DS-U4 and HL-DS-
U4-WL are configured by the factory to accept a HygroClip 2 probe. Any model of HygroClip 2
probe can be connected these using one of the available extension cables.
See document E-M-HC2-accessories.
3.3.2 1-channel analog probes with voltage output
Inputs 4, 5, 7 and 7 of docking stations HL-DS-U1, HL-DS-U2, HL-U4 and HL-DS-U4-WL can also be
configured to accept one of the following:
o 1-channel analog probe: To be compatible with the docking station the analog probe must
meet the following requirements: supply voltage: 5 VDC, current consumption: max. 10 mA,
output signal: 0 to max. 3.3 VDC. The docking station uses a 12-bit A/D converter to digitize
the probe analog signal and can be configured to measure practically any parameter.
o Analog pressure probe: this is a special case of analog probe and is subject to the same
compatibility requirements. When analog pressure probe is selected, any input of the
HygroLog HL-NT and docking station can be configured to use the signal from the pressure
probe to calculate any humidity parameter that requires barometric pressure as an input
value (example: mixing ratio).
3.3.3 1-channel analog probes with current output
Docking station HL-DS-U4-420 is similar to docking station HL-DS-U4 with the difference that it
accepts up to four 3-wire single channel analog probes with a 4-20 mA current output signal.
Each probe input uses an internal 150 Ohm resistor to convert 4…20 mA to 600…3000 mV
(nominal). The HW4 software allows a 2-point adjustment of the mA to mV conversion to
compensate for the tolerance on the 150 Ohm resistor (use Device Manager in HW4). The
probes are powered by the docking station (supply voltage: 5 VDC, maximum current draw: 10
mA / probe).
3.3.4 Pt100 RTD 4-wire probes
Docking stations HL-DS-PT2, HL-DS-PT4 and HL-DS-PT4-WL are designed for 4-wire RTD
probes. These docking stations allow the measurement of temperature conditions within the
range of -100 to 600°C. Accuracy depends on the class of the Pt100 RTD. Adjustment of the
RTD inputs against a reference temperature is limited to a 1-point adjustment (global offset).
3.3.5 Logical inputs (on / off)
Several models of docking station allow the HygroLog HL-NT to process up to 2 logical inputs.
Typically this is used to monitor a relay contact, a door contact, etc.