IN-E-HyFlex-V4_10
Rotronic AG
Bassersdorf, Switzerland
Document code
Unit
Instruction Manual
Document Type
HygroFlex transmitter version 4: instruction
manual
Document title
Page
8
of 61
© 2006; Rotronic AG IN-E-HyFlex-V2_10.doc
ZB1 Zenner Barrier for ID-EX and IW-EX
AC1617xxx Connecting Cable for ZB1
with built-in signal booster
xxx = 002 to 100
2 to 100m (about 6.5ft to 328ft)
2.2.2 Analog
probes
Depending on the model and options, the HygroFlex transmitters can be used with one or two
analog probes. Both the scale and unit of the analog input signals can be defined by software. 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 HygroFlex 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: 15 VDC or less, maximum current consumption: 10 mA. (see
page 16 – selection of the probe supply voltage).
c) Resolution is limited by the 10-bit A/D converter 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
2.3 Analog outputs (HygroFlex 1 and 3)
Model
HygroFlex 1
HygroFlex 3
analog outputs
- relative humidity
- temperature
Any three of:
- relative humidity
- temperature
- computed parameter
- user defined calculation see note
1)
below
