ROTRONIC HF8 - Manual (Page 7)

E-M-HF8-V2_10
Rotronic AG
Bassersdorf, Switzerland
Document code Unit
HygroFlex HF8 Humidity Temperature
Transmitter: User Guide Instruction Manual
Document Type
Page 7 of 35
Document title
© 2012; Rotronic AG E-M-HF8-V2_10
A custom calculation can be associated with any of the HF8 inputs. When associated with an input, the
custom calculation can in turn be associated with any of the HF8 analog outputs. The user can also define low
and high limits for a custom calculation and use these limits to generate an alarm and/or energize a relay.
Examples:
o
Difference between the humidity measured by probe 1 and probe 2
o Difference between the temperature measured by probe 1 and probe 2
o Difference between temperature measured by probe 1 and the dew or frost point calculated by probe 2
o Average of the humidity measured by probe 1 and probe 2
o Average of the temperature measured by probe 1 and probe 2
Instructions regarding custom calculations are provided in the following HW4 manual: E-M-HW4v3-F2-015,
HW4 software version 3: Device Manager – HF8 transmitter.
3.6 Real time clock
The HF8 clock keeps track of the date and time and can be adjusted from the keypad. Using the HW4
software, the clock can be synchronized with the PC date and time. The clock does not automatically adjust
for daylight saving time (DST).
3.7 Data logging function
The HF8 can log up to 10,000 pairs of relative humidity and temperature values provided by a single
HygroClip 2 probe or up to 10,000 data values provided by a single 1-channel analog probe. Both probe
inputs can be logged at the same time and in that case the recording capacity per probe is cut in half. Each
record is automatically date and time stamped. The calculated parameter cannot be recorded.
3.8 Analog outputs, relay contacts and digital interface options
The HF8 can be ordered with any of the following combinations of analog outputs, relay contacts and digital
interface:
o 4 analog output signals + 4 relay contacts (no digital interface).
o 4 analog output signals + 4 relay contacts + RS-485
o 4 analog output signals + 2 relay contacts + RS-485 + Ethernet (wired)
o Ethernet with PoE (complies with standard IEEE 802.3af)
Note: models with a RS-485 interface can be powered from a central voltage source (15…40 VDC) via the
RS-485 main data cable. In that case the HF8 should not be powered from any other source.
3.8.1 Analog output signals
All 4 analog outputs of the HF8 provide the same type of signal: 0…20 mA or 4…20 mA or 0…1V or 0…5V or
0…10V. The type of analog signal can be selected globally for all outputs after connecting the HF8 service
connector to a PC running the ROTRONIC HW4 software. No adjustment is required after changing the type
of output signal.
Using the HW4 software, each analog output can be associated with any of the two HF8 probe inputs and can
be made to correspond to one of the following:
o Relative humidity or parameter measured by an analog 1-channel probe
o Temperature
o Calculated parameter, including a Custom Calculation (if enabled)
The scale of each analog output can be set within the numerical limits of -999.99 and 9999.99. The D/A
converters used to generate the analog output signals feature a 16-bit resolution.