Leroy-Somer digitax st User Manual page 39

Figure 8-4 CT Single Word write sequence
Send first telegram
to OUT word 0
Tx_Stamp_No =
Rx_Stamp_No?
Tx_Stamp_No
The following telegrams show how to set the digital speed reference 1 (Pr 1.21) to
12553.9 rpm (32-bit value is 125539) in the Unidrive SP.
TELEGRAM 1
The first telegram from the PROFIBUS-DP master indicates a WRITE cycle by setting
the R/W bit to 0. The stamp number is set to 1. The data byte contains the menu
number for the parameter that is to be written to.
Example telegram
Bit
Value
Data word = 0x1101
Stamp number = 1
Menu = 1
When the first telegram has been received and processed in the slave node, it is
mirrored in the non-cyclic IN word. This is the signal to the master controller program
that the first telegram of the message has been received and understood and the
second telegram can be transmitted.
TELEGRAM 2
The second telegram from the PROFIBUS-DP master also indicates a write cycle, but
the stamp number is now set to 2. The data byte would contain the parameter number
for the parameter that is to be written to
Example telegram
Bit
Value
Data word = 0x1215
Stamp number = 2
Parameter = 21
When the second telegram has been received and processed in the slave node, it is
mirrored in the non-cyclic IN word. This is the signal to the master controller program
that the second telegram of the message has been received and understood and the
third telegram can be transmitted.
SM-PROFIBUS DP-V1 User Guide
Issue : a
WRITE
Start
Read IN
word 0
No
Send next
telegram
Yes
No
= 6?
Yes
b15-b12
0001
b15-b12
0001
www.leroy-somer.com
Check status
of ERR bit
Parameter
written OK
END OF
SEQUENCE
b11-b8 b7-b4
0001 0000
b11-b8 b7-b4
0010 0001
1
ERROR
Check parameter
exists, and that it is
a Read/Write
parameter
b3-b0
0001
b3-b0
0101
39