Installation and commissioning
DIGIDRIVE
Variable speed drive
92
Réf. 3218 GB - 4.33 / d - 02.02
LEROY-SOMER
7.9 - Using Modbus RTU
• Parameter setting
To enable Modbus RTU, set 4
4
1
1
= rtu, and select the transmission speed in 4
4
2
2
. Next, set the
DIGIDRIVE address in 4
4
3
3
.
• Specification of the Modbus RTU frame
The DIGIDRIVE does not use the parity bit.
• Value of the Modbus RTU register
All the DIGIDRIVE parameters are grouped together in the 4XXXX series of the Modbus
registers.
To convert a parameter to a Modbus register, remove the parameter decimal point, for
example: parameter 1
1
1
1
.
.
2
2
2
2
becomes register 1122. All parameters (including "bit"
parameters) are used as signed 16-bit values.
• Functions
When multiple read or write commands are being used, the written or read parameters should
be consecutive. If a block of parameters is written or read from a missing parameter, the slave
will respond with an exception code. It should therefore be broken down into a number of small
blocks, so that a non-existent parameter is not read or written.
The maximum number of consecutive parameters read or written is 16.
• "Broadcast" messages
The DIGIDRIVE can receive "broadcast" messages.
If the master controller sends a WRITE message to node 0, all nodes will take the message
into account, but none will respond to the master.
• Exception code
The exception codes are as follows:
1 Non-existent function code/incorrect function.
2 Register address outside the range or too many registers requested in read mode/ incorrect
data address.
Parameter outside the range during writing of block 0x10:
the slave processes the write block in the order in which the data are received. If a write
operation is not correct because a value is outside the range, the write block is ended.
However, the slave does not create an exception response, and the error is instead indicated
in the return message by the number of written data items.
Parameter outside the range during reading/writing of block 0x17:
no indication that a value is out of range will be given during access to 0x17.
1 Start bit 8 Data bits 2 End bits
0x03 (3) Reading multiple parameters
0x10 (16) Writing multiple parameters
0x17 (23) Reading and writing multiple parameters
To Next Page
Loading...
Need help?
General
