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!04AV00005 Return of averaging time
It is also possible to specify the ID on start-up via the external PINs WV/RXD- , WD/RXD+ and
ADIO. For this purpose the parameters of the commands AA, AB, AC and XI must be set properly:
see Command AA , Command AB , Command AC , Command XI.
7.1.8 Bus mode
The concept of ID-based communication allows the ULTRASONICs to be operated in a bus
system. The prerequisites for this are:
•
half duplex mode
•
different IDs of the individual bus users
•
master-slave structure, i.e. there is a device in the bus (control, PC ...) that performs cyclic
enquiry of the data of the individual ULTRASONICs and possibly parameterises the
ULTRASONICs.
In bus mode there are no restrictions on parameterisability and program upload. A station can also
be provided with a new program in bus mode for a specific purpose. With an update a program
update must be performed for every ULTRASONIC.
In bus mode it is recommended not using an ULTRASONIC with the ID '00' as this ID is reserved
for devices that are integrated in the bus for the first time.
7.2 Analogue and digital I/O
In addition to output of the data via the serial RS485, the ULTRASONIC can also output the data
using an analogue interface. These outputs can also be optionally switched as analogue inputs
which read in an external voltage of 0.. 9.96V, perform digital conversion and output this via the
user-specific telegram.
The ULTRASONIC is also equipped with the cable ADIO, which includes digital output functions in
addition to the analogue input.
7.2.1 Analog inputs
The signals WV/RXD-, WD/RXD+ and ADIO of the connector can be switched as analogue inputs
under certain conditions. WV/RXD- and WV/RXD+ are then only available as inputs when half
duplex mode is selected and the ports have been set accordingly via the commands AA, AB and
AC.
See Command AA , Command AB , Command AC.
The function of the pin ADIO is independent of duplex mode and can be switched as an analogue
input at any time.
The measured values read-in can be output with the user-specific telegram: see User-specific
telegram. The input voltage range is 0…+10,0V, the sampling rate can be set in many ranges by
the command AU (analogue Update rate). The minimum converting period is 2,5 msec per
channel. If, for ex., all three channel are configured as analogue inputs, the maximum sampling
rate is 1/7,5 ms = approx. 133 Hz.
The parameter AU gives the sampling rate in ms. The time period of a sampling for all selected
analogue channels is the value of AU multiplied by the number of channels.
The scanning rate can be changed through the command AU. The parameter gives the scanning
interval in ms. The scanning rate for all analogue channels is the value of AU, multiplied by the
number of channels.