Danfoss VLT AAF00x, Инструкция по эксплуатации, Страница: 98 / 117

7.3.2 Message Structure
Each message begins with a start character (STX)=02 Hex,
followed by a byte denoting the message length (LGE) and
a byte denoting the filter address (ADR). A number of data
bytes (variable, depending on the type of message)
follows. The message is completed by a data control byte
(BCC).
STX LGE ADR DATA BCC
195NA099.10
7.3.3 Message Length (LGE)
The message length is the number of data bytes plus the address byte ADR and the data control byte BCC.
The length of messages with 4 data bytes is LGE = 4 + 1 + 1 = 6 bytes
The length of messages with 12 data bytes is LGE = 12 + 1 + 1 = 14 bytes
The length of messages containing texts is 10 1) +n bytes
1)
The 10 represents the fixed characters, while the “n’” is variable (depending on the length of the text).
7.3.4 Filter Address (ADR)
Two different address formats are used.
The address range of the filter is either 1-31 or 1-126.
1. Address format 1-31:
Bit 7 = 0 (address format 1-31 active)
Bit 6 is not used
Bit 5 = 1: Broadcast, address bits (0-4) are not used
Bit 5 = 0: No Broadcast
Bit 0-4 = Filter address 1-31
2. Address format 1-126:
Bit 7 = 1 (address format 1-126 active)
Bit 0-6 = Filter address 1-126
Bit 0-6 = 0 Broadcast
The slave returns the address byte unchanged to the master in the response message.
7.3.5 Data Control Byte (BCC)
The checksum is calculated as an XOR-function. Before the first byte in the message is received, the calculated checksum is
0.
7.3.6 The Data Field
The structure of data blocks depends on the type of message. There are three message types, and the type applies for both
control message (master=>slave) and response messages (slave=>master).
The three types of message are:
RS-485 Installation and set... VLT Active Filter AAF 00x
MG.90.V2.22 - VLT
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