ROTRONIC HygroLab - Manual (Page 6)

IN-E-HyLab-V4_11
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
Instruction Manual
Document Type
HygroLab bench top indicator version 4:
instruction manual
Document title
Page 6 of 51
© 2006; Rotronic AG IN-E-HyLab-V4_11
have a T7 connector (not shown here). These probes can be connected to the HygroLab with the
T7-03-B5 adapter cable.
AW-DIO and AwVC-DIO water activity probes
Direct connection to the HygroLab
(probe has a B5 connector)
2.2.2 Analog probes
The HygroLab can be used with one or more analog probes. The corresponding probe input(s) as
well as
the scale and unit of the analog input signal(s) should be programmed with the HW4 software prior to
using the probe(s) . For example, an analog pressure probe may used to provide the local value of
barometric pressure for the computation of parameters such as the wet bulb temperature, mixing
ratio or enthalpy.
Use of analog probes is subject to the following restrictions and limitations:
a. ROTRONIC analog humidity-temperature probes with the standard temperature output signal of
– 0.5…2.0 V = -50…200 °C: because the HygroLab cannot read a negative voltage signal,
temperature measurement is generally limited to values above freezing.
b. Third-party analog probes: single channel probes (one signal), output signal within the range of
0 to 2.5 VDC, supply voltage: 9 VDC or less, maximum current consumption: 10 mA.
c. Resolution is limited by the 10-bit A/D converter 1) used for the analog inputs. This converter
provides a theoretical maximum of 1024 counts for an input voltage span of 2.5 VDC. In theory,
this gives a resolution of 2.5 / 1024 = 0.00244 V. In practice, it is not possible to get 100% of the
counts from an A/D converter and the actual resolution should be about 0.0027 V (typical). For
example, if a probe with a temperature signal of 0…1 V = 0…100
°C is being used, the signal
resolution will be about 100 x 1 x 0.0027 = 0.27 °C.
1) HygroLab 3: 12-bit A/D converter
2.3 Analog outputs (optional)
Analog outputs are optional on the HygroLab 2 and 3. These outputs simply repeat the analog
inputs (if any analog probe is being used). See Connectors - Optional analog output connector.