Delta Controls eZFC-424R4-24, Инструкция по применению

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eZFC-424R4-24 Application Guide
Edition 2.6 Page 61 of 84
The time-proportional algorithm scales the heating and cooling output using these maximum and
minimum values:
l
the minimum (TimePropHtgMin AV152) and maximum heat output (TimePropHtgMax
AV153)
l
the minimum (TimePropClgMin AV150) and maximum cooling output (TimePropClgMax
AV151)
For each heating or cooling stage, the algorithm calculates how long the active heating or cooling
output object is turned on using the following formula: (heating used as an example)
Hydronic outputs "active" time = TimePropPeriod/100 * (heating stage output% *
(TimePropHtgMax - TimePropHtgMin)/100 + TimePropHtgMin)
Electric output "active" time = TimePropPeriod /100 * heating stage output% *
TimePropHtgMax/100
The time period when the output object is turned off = TimePropPeriod - "Active" time.
For electric duct or electric baseboard outputs set up as time-proportional, the minimum heat
output % is ignored by the algorithm to prevent overheating, even when the minimum heat output is
greater than 0. The maximum heat output % still applies to honour the system's upper safety limits.
For hydronic heat outputs, both minimum and maximum heat output % are used.
For programmable controllers, if custom output objects are used, the pulse has a 100% duty cycle.
The output is directly controlled by a GCL program and the custom AV objects are used to
modulate the pulse.
Auto Changeover
The temperature of the supply water delivered to the hydronic coils in a 2-pipe fan coil configuration
automatically determines what its output (HeatCoolx) will do.
When the supply water temperature is below 20°C (68°F), the HeatCoolx output is in cooling
mode. At temperatures above 25°C (77°F), the HeatCoolx output is in heating mode. Between 20
and 25°C, the output can either be heating or cooling.
The active output mode is saved in the MV803 object (HeatCoolChangeOverStatus).
Discharge Air Temperature
The discharge air temperature (DAT) is the duct temperature downstream from any local heating
or cooling stages that supply the air to that space. This section applies to a space with a DAT
sensor and ducted heating or cooling stages.