FC101 Design Guide
STX LGE ADR DATA BCC
195NA099.10
Figure 7.5 Telegram Structure
7.4.3 Telegram Length (LGE)
The telegram length is the number of data bytes plus the
address byte ADR and the data control byte BCC.
4 data bytes LGE = 4+1+1 = 6 bytes
12 data bytes LGE = 12+1+1 = 14 bytes
Telegrams containing texts
10
1)
+n bytes
Table 7.4 Length of Telegrams
1) The 10 represents the xed characters, while the n is variable
(depending on the length of the text).
7.4.4 Frequency Converter Address (ADR)
Address format 1–126
•
Bit 7 = 1 (address format 1–126 active).
•
Bit 0–6 = frequency converter address 1–126.
•
Bit 0–6 = 0 broadcast.
The slave returns the address byte unchanged to the
master in the response telegram.
7.4.5 Data Control Byte (BCC)
The checksum is calculated as an XOR-function. Before the
rst byte in the telegram is received, the calculated
checksum is 0.
7.4.6 The Data Field
The structure of data blocks depends on the type of
telegram. There are 3 telegram types, and the type applies
for both control telegrams (master⇒slave) and response
telegrams (slave⇒master).
The 3 types of telegram are:
Process block (PCD)
The PCD is made up of a data block of 4 bytes (2 words)
and contains:
•
Control word and reference value (from master to
slave).
•
Status word and present output frequency (from
slave to master).
ADRLGESTX PCD1 PCD2 BCC
130BA269.10
Figure 7.6 Process Block
Parameter block
The parameter block is used to transfer parameters
between master and slave. The data block is made up of
12 bytes (6 words) and also contains the process block.
PKE INDADRLGESTX PCD1 PCD2 BCC
130BA271.10
PWE
high
PWE
low
Figure 7.7 Parameter Block
Text block
The text block is used to read or write texts via the data
block.
PKE IND
130BA270.10
ADRLGESTX PCD1 PCD2 BCCCh1 Ch2 Chn
Figure 7.8 Text Block
7.4.7 The PKE Field
The PKE eld contains 2 subelds:
•
Parameter command and response (AK)
•
Parameter number (PNU)
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
130BB918.10
PKE IND
PWE
high
PWE
low
AK PNU
Parameter
commands
and replies
Parameter
number
Figure 7.9 PKE Field
Bits 12–15 transfer parameter commands from master to
slave and return processed slave responses to the master.
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