Future Design MCT-CM, Руководство пользователя

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MCT-CM
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4.5.1 Setting the Defrost Enable Outputs
In order for defrost to operate, timed or timed process, an output must be selected as an enable for the defrost
logic. When the output is on, the defrost interval timer will begin operation. Note that if timed process is
selected, the enable loop/monitor point must also be below the enable setpoint. As long as the output remains
on, defrost will continue operation.
The output(s) is used as the switch to activate defrost. This allows defrost to be turned on and off in conjunction
with the system it is associated with. If at any time the enable output(s) is off, defrost operation will be
terminated. There must be at least one output selected in order for defrost to operate regardless of the selected
type. To select which output(s) is to be used, press the
“Enable Outputs” button.
For example, if digital output 1 is used as the control output for the refrigeration system when a system event
is turned on, then select digital output 1 from the list. This will enable the defrost logic whenever the refrigeration
system is on. Additional outputs can be selected if necessary. Once all selections have been made, press the
‘Done’ button to accept the output selections and return to the Defrost Setup screen.
NOTE: Control outputs for defrost and precool (that activate when defrost or precool are active) are
configured under Digital Output Setup in the MCT runtime application.
4.5.2 Setting Defrost/PreCool Output Defeats
The defrost and precool output defeat selections allow the OEM to select which outputs should be disabled
during defrost and precool. This allows specific equipment to be disabled during defrost operation such as a
fan or cooling valve for example.
The
Defrost Output Defeats button allows the OEM to select which outputs should be disabled during defrost.
The
PreCool Output Defeats button allows the OEM to select which outputs should be defeated during precool.
Precool, otherwise known as fan delay, occurs immediately after the defrost duration has completed. In typical
refrigeration applications, this allows the OEM to defeat cooling systems and fans during defrost, but then allow
the cooling systems to operate during the precool period while keeping the fan off. This allows the cooling coil
temperature to be lowered prior to turning the system fans back on and minimize temperature rise in the
conditioned space.