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Operation
induSENSOR DTD / MSC7xxx
5.5.1
Operation on the RS485 Bus with Multiple Channels
The connection to the RS485 bus enables to directly read out the measurement values
.
The respective addresses can be individually set from 1 ... 126.
Please avoid in each operating mode using the same addresses multiple times on the bus.
> Data collision / System crash
With the MSC7401 and MSC7802 models, the addresses can exclusively be set via software
. The
MSC7602 model in addition enables to set the address via a DIP switch
.
The MSC7602 and MSC7802 2-channel variants hold a special status.
When the addresses are firmly assigned via DIP switch
, always both addresses are set, e.g.,
channel 1 = address 100
channel 2 = address 99.
However, if the addresses are assigned via the sensorTOOL
, the addresses can be set individual-
ly. But channel 1 only allows even address values while channel 2 only allows odd address values. If an entry
is incorrect, the addresses are automatically set to the next higher even address or the next lower address.
i
Please note that the transmission frequency per channel is reduced as the number of participants on
the bus increases, as all channels have to be queried in series. Per channel, the duration of a message
(query and response) is approx. 3 ms with 256,000 baud.
When using the
sensorTOOL
program on Windows, a maximum data rate of only 12 ms per message
is possible.
The maximum number of participants (incl. master) on a bus line is 64. Depending on the length of the
line and environmental conditions, an external terminating resistor may be required.
Fig. 63 DIP switch on the MSC7602 for multi-channel operation
