Inhaltsverzeichnis
Werbung
Verfügbare Sprachen
Verfügbare Sprachen
2
Protocol description
2.3
Device address
The device address of the slave can be set between 0 and 254. Device address 0
is reserved.
A maximum of 31 slaves can be addressed via the RS485 interface.
There are two different forms of data exchange:
Query
Data request/instruction by the master to a slave via the corresponding device address.
The slave addressed responds.
Broadcast
Instruction by the master to all slaves via the device address 0 (e.g. to transmit a specific
value to all slaves).
T he connected slaves do not respond. In such a case, the correct acceptance of the value
by the slaves should be checked by a subsequent readout at each individual slave.
Data request with the device address 0 is meaningless.
2.4
Timing of the communication
S tart and end of a data block are marked by transmission pauses. The
maximum permitted interval between two consecutive characters is three times the
transmission time required for a single character.
T he character transmission time (time required to transmit one single character)
depends on the baud rate and the data format used (stop bits and parity bit).
F or a data format of 8 data bits, no parity bit and one stop bit, this is:
character transmission time [ms] = 1000 * 9 bit/baud rate
F or the other data formats, this is:
character transmission time [ms]
= 1000 * (8 bits+parity bit+stop bit(s)) bit/baud rate
6 | nVent.com
Werbung
Inhaltsverzeichnis
