Modbus Registers OPTIMA...GOMOD
Short instruction 227VM-024-05-MB 
Written by: Michael Köhle    Date: 13.11.2014 08:56:00  Side 13 of 13
2.1.7.  Description interface parameter Modbus 
Display 
Number 
EEPROM-
value  Baudrate  Parity  Stop bits 
1  0  1200  none  2 
2  1  1200  even  1 
3  2  1200  odd  1 
4  3  2400  none  2 
5  4  2400  even  1 
6  5  2400  odd  1 
7  6  4800  none  2 
8  7  4800  even  1 
9  8  4800  odd  1 
10  9  9600  none  2 
11  10  9600  even  1 
12  11  9600  odd  1 
13  12  19200  none  2 
14  13  19200  even  1 
15  14  19200  odd  1 
16  15  38400  none  2 
17  16  38400  even  1 
18  17  38400  odd  1 
3. Remarks 
The standard value for V
nom
 of the 227VM-024-05-MB model is 250 Pa. If you want to adjust the V
nom
value to 150 Pa (normal value you’re using) there are several ways doing it: 
1.  Use our VAV software and the interface and change the value to 150 Pa and the air flow, con-
firm the values by pressing enter. 
2.  Use a software for the Modbus communication e.g. Modbus poll and write in register 200 the 
new value e.g. 150 Pa the written value needs to be 15000. Then it is also possible to set a new 
airflow at this differential pressure. Write the password (FFFF
h
) in register 1793 to unlock regis-
ter 523 and write in the desired value. Lock register 523 by writing the value 0 to register 1795. 
There are two different possibilities using the actuator in proportional control mode (register 201): 
Writing the value 4 into the register 201 (pre-set) and the display will indicate this with the dot 
on l/s, the second possibility is writing the value 5 in the register this will be indicates with the 
dot on m
3
/h. 
In general the actuator can be used as analogue model (register 122 = 0) then it’s regulating according 
to the applied voltage on input Y. The second option is that it’s controlled via Modbus   (register 
122 = 1). Then the desired position can be set in % via register 0, e.g. 10% = 1000. 
The feedback signal provides the output signal according to the selected mode (0(2)…10 V) related to 
the nominal flow. 
Example:  V
nom
 is 100 l/s @ 250 Pa, V
act
 = 10 l/s  feedback signal (theoretical) = 1 V. 










