Heating/Cooling sequences

Access 4.x

The setpoint temperature of the supply air controller is reached by regulating the capacity of physical exchangers, heaters and coolers. Number of heating/cooling sources might differ therefore Access is made flexible to cover the most common variations.

It is also possible to utilize air mixing as the source for heating/cooling. If air mixing is used, the control of the recirculation sequences can be enhanced by the air quality control function.

Fan setpoints compensation sequences can also be used as part of the temperature regulation process. The sequences can be used to: e.g.

compensate the insufficient heater power by reducing airflow.
increase airflow in order to utilize DX cooler more efficiently.

Note! Starting with Access version 4.5-1-01 - the fan setpoint compensation sequences can bypass the usual sequence starting order if certain conditions are met.

Each heating/cooling source in the system has to be configured in Access. Configuration includes:

configuring a Sequence regulator
adjusting PID settings
allocating inputs and outputs for hardwired interface
adjusting operational settings (setting operation allowances and restrictions)

The Sequence regulator (a.k.a. "Sequence") is an intermediary between the supply temperature controller and the physical heater/cooler. It assures that the physical component operates in a safe and efficient manner.

Up to 10 sequences can be used. For standardization the sequences have designated letter (SEQ-A to SEQ-J) and predefined names to cover the most frequent configurations.

Despite of their names - all the sequences share the same functionality and can be used for other purposes then name is suggesting. However it is recommended to use each sequence for the function it is named after as it effects the correct display of the flowchart.

Configuration > Functions > Function activation > Heating/Cooling sequences
Position	Heating	Cooling	Start Heating	Start Cooling	Name
SEQ-A	2	Off	0%	0%	Heating
SEQ-B	1	1	0%	0%	Exchanger
SEQ-C	Off	2	0%	0%	Cooling
SEQ-D	Off	Off	0%	0%	Recirculation 1
SEQ-E	Off	Off	0%	0%	Recirculation 2
SEQ-F	Off	Off	0%	0%	Fan setpoint compensation
SEQ-G	Off	Off	0%	0%	Heating 2
SEQ-H	Off	Off	0%	0%	Cooling 2
SEQ-I	Off	Off	0%	0%	Exchanger extract
SEQ-J	Off	Off	0%	0%	Extra heating/cooling capacity

The supply temperature controller regulates to a comfortable temperature. It can activate a single sequence for a slight temperature adjustment or a few sequences at once if the significant adjustment is needed.