Leroy-Somer digitax st User Manual page 38

TELEGRAM 6
The sixth telegram from the PROFIBUS-DP master acts as the indication to the slave to
send the low data byte from the requested parameter. The data byte is not used in this
telegram and should be set to 0.
Example telegram
Bit
Value
Data word = 0x9600
Stamp number = 6
When the sixth telegram has been received and processed in the slave node, the node
will mirror the stamp number in the non-cyclic IN word and load the low byte of the
parameter value into the data byte.
Example response
Bit
Value
Data word = 0x96DC
Stamp number = 6
Data low byte = 0xDC = 220
8.7.2 The parameter re-assembled
The completed value can be assembled as follows to give the complete value as read
from the parameter.
Speed
8.7.3 Writing parameters using CT Single Word
To write to a 32-bit parameter using the non-cyclic channel, the following telegrams
must be sent one telegram per network cycle to construct the final message.
• Telegram 1 - define menu number
• Telegram 2 - define parameter number
• Telegram 3 - send high data byte
• Telegram 4 - send mid-high data byte
• Telegram 5 - send mid-low data byte
• Telegram 6 - send low data byte
38
b15-b12
1001
b15-b12
1001
24
= (High byte * 2 ) + (Mid-high byte * 2
(Mid-low byte * 2
= (0 * 16777216) + (1 * 65536) + (37 * 256) + 220
= 75228
= 7522.8 rpm
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b11-b8 b7-b4
0110 0000
b11-b8 b7-b4
0110 1101
16
) +
8
) + Low byte
SM-PROFIBUS DP-V1 User Guide
b3-b0
0000
b3-b0
1100
Issue : a