Setpoint Offset; Settings; Operation - Procon MelcoBEMS MINI Installation Manual

5. Setpoint Offset

The Setpoint Offset feature is only applicable to, and will only be enabled for, Air-To-Air type units.

5.1. Settings

There are two settings which are applicable to the Setpoint Offset feature, BMS Room Temperature and BMS Virtual
Setpoint.
The BMS Virtual Setpoint can be changed using Modbus and is stored in non-volatile memory so the value is retained
if the MelcoBEMS MINI (A1M) loses power.
The BMS Room Temperature can be changed using Modbus but is not stored in non-volatile memory, so the value is
lost and reset to zero upon the MelcoBEMS MINI (A1M) losing power.

5.2. Operation

rd
In some situations a 3 party room temperature sensor connected to a BMS or other controller may provide a more
accurate temperature reading than the return air temperature of the indoor unit. The A1M can calculate the difference
between these two temperature readings and compensate by adjusting the indoor unit's temperature setpoint.
The new temperature setpoint is calculated using the following equation:
Temperature Setpoint = Return Air Temperature – (BMS Room Temperature – BMS Virtual Temperature)
As a hypothetical example, consider the BMS Virtual Setpoint being set to 21ºC and the indoor unit return air
temperature remaining constant at 22ºC. As the BMS Room Temperature decreases the MelcoBEMS MINI (A1M)
increases the indoor unit's temperature setpoint.
When the BMS Room Temperature reaches 18ºC the Temperature Setpoint = 22 – (18 – 21) = 25ºC.
Hysteresis has been built in to prevent the temperature setpoint from rapidly changing.
Page 10 of 47