JVL Industri Elektronik A/S - User Manual - Integrated Stepper Motors MIS23x, 34x, 43x 261
11.1 Modbus in MIS34x and SMC85
Often the graphical program in the motor is used to write to Register 121, ModbusSetup,
possibly after an initial delay, or as the result of a hardware input.
Set Register 121 to 25 (8 data bits, Even Parity, 1 stop bit).
The baudrate is unchanged after the switch from MacTalk to Modbus. It is recommended
to first configure the baudrate using MacTalk, and save this to flash memory.
Register 121, ModbusSetup, supports the following bit-fields
(default values marked with *):
Below is the basic data format for the two supported operations 3 and 16 (0x10 hexa-
decimal):
Read Holding operation:
Request: <adr>, 0x03, RegHi, RegLo, CountHi, CountLo, CRC1, CRC2
Offset: [0] [1] [2] [3] [4] [5] [6] [7]
Reply: <adr>, 0x03, #Bytes, Reg0Hi, Reg0Lo, Reg1Hi, Reg1Lo, ..... CRC1, CRC2
Example to read P_IST (register 10) from a motor with address 254, values in decimal:
254, 3, 0, 20, 0, 2, NN, MM (NN and MM are the CRC-16 bytes)
Write Multiple Register operation:
Request: <adr>, 0x10, RegHi, RegLo, CountHi, CountLo, NBytes, Val0Hi, Val0Lo, ..., CRC1, CRC2
Offset: [0] [1] [2] [3] [4] [5] [6] [7] [8]
Reply: <adr>, 0x10, RegHi, RegLo, CountHi, CountLo, CRC1, CRC2
Example to write P_SOLL (register 3) to motor with address 254, values in decimal:
254, 16, 0, 6, 0, 2, 4, bb, aa, dd, cc, NN, MM(NN and MM are the CRC-16 bytes)
Bits Values Description
0 0=Disabled *,
1=Enabled
When set to non-zero, selects to start the switch away from
the MacTalk protocol and start the Modbus protocol.
1 0=Modbus RTU*,
1=Modbus ASCII
This field is not current used. The motor always uses the
binary Modbus RTU format.
3:2 0=No parity,
1=Odd parity,
2=Even parity
Select the parity bit value. Select the same format as the
Modbus client PLC, HMI or PC uses. (3:2 is read as 'bits 3
through 2')
4 0=7 data bits,
1=8 data bits
Number of data bits in a byte. Modbus RTU always uses 8
bits per byte.
5 0=1 stop bit,
1=2 stop bits
Select the number of stop bits. Select the same format as
the Modbus client PLC, HMI or PC uses
31:6 Reserved Reserved for future use. Please set all of these bits to zero.
Only MIS34x
TT2346-01GB
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