The Modbus address for a parameter is the sum of the Address in the Utility Software
(USW) and the first value of the address area. To find the address of a specific parameter,
go to the Parameters tab in the USW, then find the parameter using the parameter's
name or parameter number (Channel column). The parameter address is located in the
Address column.
Alarm example
Acknowledge alarm
In this example an over-voltage 1 alarm is active and unacknowledged.
First we will check if the alarm is already acknowledged, then
acknowledge the alarm using Modbus.
The parameter number for the over-voltage 1 alarm is 1150. Find the
parameter in the USW in the Parameters tab and note the
Address value for the parameter (12 for over-voltage 1).
The parameter numbers are listed in the Channel
column.
To read if the alarm is acknowledged, go to the table in Address
areas > Read discrete input (Function code 02). The address
area for Alarm acknowledge starts at 6000.
The Modbus address to read the parameter is: Parameter Address
+ Address area start = 12 + 6000 = 6012.
Use function code 02 to read address 6012.
For this example when the address is read, the controller
returns 0 (FALSE). This means that the alarm is not
acknowledged.
To acknowledge the alarm, go to the table in Address areas > Write
single/multiple coils (Function code 05/15). The address area
for Acknowledge alarm starts at 6000.
The Modbus address to read the parameter is: Parameter Address
+ Address area start = 12 + 6000 = 6012.
Use function code 05 to write 1 (TRUE) to address 6012.
The alarm is now acknowledged and reading address 6012 using
function code 02 returns 1 (TRUE). This means the alarm
is acknowledged.
Nominal setting example
Change nominal frequency
In this example nominal frequency 1 is changed from 50 Hz to 60 Hz.
The parameter number for the nominal frequency 1 is 6001. Find the
parameter in the USW in the Parameters tab and note the
Address value for the parameter (407 for nominal frequency
1).
To change the nominal frequency, go to the table in Address areas
> Write single/multiple holding registers (Function code
06/16). The address area for Values used starts at
4000.
The Modbus address to write the new value to is: Parameter
Address + Address area start = 407 + 4000 = 4407.
The nominal frequency has a scaling of 1. See Data scaling*
for the exponential scaling formula and examples. To write 60 Hz to
the address, a value of 600 must be written to the address. Use
function code 06 to write 600 to address 4407.
Nominal frequency 1 is now 60.0 Hz. To confirm the change use
function code 03 to read address 4407. The address returns 600.
(The scaling is also 1.)
Note: * A measurement's scaling in the Modbus tables is not necessarily the
same as the scaling for the corresponding parameter. For example, the scaling for the
frequency measurement is 2, while the scaling for the nominal frequency parameter is
1.