How to control back-up equipments based on a defined ΔT from the setpoint temp

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Hello Everyone,

I finished modeling the HVAC system of a loft. On the cooling side, it is served by both Low Temperature Radiant Floors (which run on free-cooling) and FCUs (the last ones just as a back-up for those situations in which free-cooling cannot meet loads).

The control logic is the following:

• FCUs only start when the indoor mean air temperature (Ta) is 2°C above the setpoint temperature (Ts) which means Ta > Ts + 2°C
• FCUs shut-off as soon as the indoor mean air temperature (Ta) is backed up to 0.5°C above the setpoint temperature (Ts), which means Ta = Ts + 0.5°C

I guess I should use EMS but I honestly have no idea on how to set this logic up. Any hints?

Thank to everyone could help me.