IFM Electronic ecomat 300 AC1155, Руководство по эксплуатации устройства

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RS-485 gateway
4
Parameter data is stored permanently in the slave memory� Since the
process of storing takes several 100 ms, the CTT2 communication will stop
and resume after a reset of the device only�
4.1 Receiving data via the RS-485 gateway
The slave cyclically transmits the number of bytes that have been received and
that are available for reception via AS-Interface� The receive buffer in the slave has
a size of 64 bytes�
The master should then send "18, 3, xx" (acyclic read service request to index 3
with a usable length of xx bytes) to collect the information�
If more than 32 bytes are in the buffer, the command may be issued several times
with a maximum length of 32 bytes until the buffer is empty� If there are fewer
bytes in the buffer than required, the response contains all available bytes� If an
acyclic read service request to index 3 is issued while the buffer is empty, the
response is an error "illegal length"�
If single bit transmission errors occur, AS-Interface will repeat faulty telegrams and
recover lost information� If byte transmission errors occur, the data may be lost�
4.2 Sending data via the RS-485 gateway
The master sends "19, 3, xx, ��� data���" (acyclic write service request to index 3
with a usable length of xx bytes) to transmit the output information�
If more than 32 bytes are to be transmitted, this write service may be repeated
several times with a maximum length of 32 bytes� Since the RS-485 interface is
faster than AS-Interface, there is no danger of buffer overrun�