User manual

OPERATION MANUAL
Technical changes reserved
0141 0316-25 19.08.2015
USB-I²C-adapter
for B+B Temperature-module with I²C-output
Now, in order to fetch further measured values, every time you will
have to enter:
IR_78004 <CR>
Each time the USB-module replies with the current measured values.
Interpretation of values
The left four hex numbers are the rst channel (e.g. humidity or pres-
sure) and the following four hex numbers are the values of second
channel, usually for the temperature of the module, if used.
Conversion of measured values
The following example refers to the Humidity-Temperature module
and the transmitted string ‚3EEF4499 ‚ in the answer:
The front four digits ‚3EEF‘ are the humidity value, the following digits
‚4499‘ are for the temperature value in hexadecimal format.
Now, rst the Humidity value is converted from HEX to decimal (in
example 16111) and then divided by 327,68 as per the data sheet. On
rounding the two post comma places, the humidity value in decimal
format comes out as 49.17 % RH.
The Temperature value is also rst converted into decimal (17561)
and then divided by 256 as per data sheet and 32 is subtracted from
the result.
After rounding off the two post comma places, it results in the tempe-
rature value of 36.60 °C.
With the other modules under consideration. One has to proceed in the
same way as per data sheet.
For further information, visit our website:
www.bb-sensors.com
Module
Channel 1 Channel 2
Humidity module rel. humidity un-calibrated
Feuchte-
Humidity-Temp. module rel. humidity Temperature
PT1000
PT1000 Temp. module
PT1000
Temperature un-calibrated
Thermoelemente
Thermo element
Temp. module Thermovoltage
Temperature
calibration point
Pressure module Pressure un-calibrated
Command overview for examples
The USB-adapter has a very extensive command set. Detailed de-
scription is available on the enclosed CD. The following explanations
are only related to the commands used in the above examples:
‚V‘ Statement of version string
This command responds back with the version string of the controller
Firmware.
‚T11200‘ Initialising
Denition of operating voltage and the time delay before the rst com-
munication. This command must be sent before the rst I²C commu-
nication takes place. The last 3 digits are for the time delay after swit-
ching on the operating voltage and before the rst reading of measured
value.
‚IRT78004‘ I²C Read with on-timing
This command switches on the operating voltage, waits for the time
delay as dened in the initialising sequence and then nishes reading
over I²C at the address stated in the ASIC.
The rst two digits (78) are the 7-bit I²C address of the ASIC. The fol-
lowing 3 digits (in example 004) determines the number of digits to be
read.
The ASIC always responds to the address 78, however it can also
be programmed at another address, so that it is possible to operate
several ASICs at the same I²C-Bus.
The time delay enables the ASIC to carry out a measurement after
feeding the operating voltage,
before the measured values are read out rst time.
The operating voltage remains switched on even afterwards. Hence,
the IRT command is required only for the rst time to switch on the
operating voltage.
‚IR_78004‘ I²C read
This command is identical to the previous one, however without switch
on of the operating voltage and without time delay.
This I²C-read command is used for all further read operations in res-
ponse.
B+B Thermo-Technik GmbH | Heinrich-Hertz-Straße 4 | D-78166 Donaueschingen
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