Rev. 0 - 05/11/2020
OPERATING MANUAL
OPERATING MANUAL
EN
EN
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17. VARIABLE SWITCHING FREQUENCY (for 3-phase - 4 kW only)
This feature is used to increase the efficiency and to decrease the heating of the fan. At slow fan speed the driver switching fre
-
quency is set at its maximum value 14kHz, while at high speed, the switching frequency is reduced to 8kHz. In this situation the
noise generated by the lower switching frequency is covered by the higher fan noise.
18. COMMUNICATION
Protocol interface:
MODBUS RTU (RS485 or Bluetooth)
Baud rate
The baud rate can be set through the
Holding Register 47
and the possible speeds are:
RS-485 CABLE
: 9.6kbps and 19.2kbps (higher speeds are not allowed due to the board Opto-Insulators)
UART OFFLINE CABLE
: 9.6kbps, 19.2kbps, 38.4kbps and 57.6kbps.
Parity and Stop bits
The parity and the stop bits can be chosen by modifying the
Holding Register 48
and the possible choices are:
0
No parity, 2 Stop Bits (default)
1
Odd parity, 1 Stop Bit
2
Even parity, 1 Stop Bit
Supported Function:
03
Read Holding Registers
04
Read Input Registers
06
Write Single Holding Register
Modbus Communication Timeout
With this feature it is possible to stop the fan when the communication is lost, after a period of time set in the
Holding Register
56
. The register can be set to:
0
No Communication Timeout
1 to 32767
Time expressed in seconds, therefore it is possible to set
from 1sec to 9h 6m 8 sec
The value of the Holding Registers is NOT coerced if trying to set a not allowed value.
When trying to enter a value in any holding register, the value is not overwritten if the new value is outside the load boundaries.
When the timeout occurs, the driver goes in alarm condition and the communication must be restored and the alarm must be
cleared. The alarm is indicated in the Input register 17 with the value of 255 (0xFF).
