User guide

MDX-ETHERNET User Guide 31
Issue : a www.leroy-somer.com
8 Non-cyclic data (acyclic)
8.1 What is non-cyclic data?
Non-cyclic data allows access to any parameter without the need to use cyclic data
transfers. This is particularly useful when accessing many different parameters for setup
or archiving of drive settings.
8.2 Modbus register number by acyclic parameter
Modbus register number by acyclic parameter
This parameter defines if a register take one or two word in modbus (for read or write
non-cyclic).
8.3 How to read and write non-cyclic Modbus
MDX-ETHERNET supported various Modbus function codes to write and read non-
cyclic:
• Function 03 (FC3) Read holding Registers
• Function 06 (FC6) Write Single Register
• Function 16 (FC16) Write Multiple Registers
• Function 23 (FC23) Read/Write Multiple Registers
The modbus address for read and write non-cyclic is dependent of the parameter
Pr 15.09 and if master manage address -1. See table 8.1 for more information.
Table 8.1 How define non-Cyclic Modbus address
Pr 15.09
Default 1 (2 registers by parameter)
Range 0 (1 register by parameter) to 1
Access RW
If Pr 15.09 = 1 register, it's not possible to access at all parameters 32 bits.
NOTE
Drive mode Calculate Modbus address
Example 1 :
- Modbus address for read
or write to Pr 1.21
- Master software with no
management of address -1
(modbus address =
real address)
Example 2 :
- Modbus address for read
or write to Pr 1.21
- Master software with
management of address -1
(modbus address =
real address -1)
Pr 15.09 = 2
registers
(drive default
parameter)
First address non-cyclic =
0x210 = 528
Address =
528 + [(parameter - 1) *2]
528+ [(121-1)*2] = 768
Modbus address = 768
528+ [(121-1)*2] +1 = 769
Modbus address = 769
Pr 15.09 = 1
register
First address non-cyclic =
0x210 = 528
Address = 528 + parameter -1
528 + 121-1 = 648
odbus address = 648
528 + 121 = 649
Modbus address = 649
- Function 06 (FC06) is not work with parameter 32 bits.
- All Function is not work with parameter 32 bits if length access is less than 32 bits.
With PLC Master, LEROY-SOMER advise to used Function 03 to read and Function 16
to write (this functions is generally used in all PLC).
At the first read or write acyclic function and if Cyclic is not used, OUT mapping
parameter (see Pr 15.20 to Pr 15.29) are set to zero.
NOTE
NOTE
NOTE