Humidity Sensor-Discharge Air Control (Dac) Unit; Field Binary Input Signals; Manual Cooling And Heating Enable; Cooling Enable - Daikin MicroTech II Installation And Maintenance Manual

Humidity Sensor—Discharge Air Control (DAC) Unit
A humidity sensor can be wired to terminals 126, 127 and 131
on TB2 on a discharge air control (DAC) unit as shown on the
unit wiring diagram or Figure 16 on page 39. However, this
input is not used for control purposes and the current relative
humidity value from the sensor cannot be read via the keypad/
display. The current value from the sensor can be read via a
network interface only.

Field Binary Input Signals

The following sections describe options that, if used, require
field wiring to binary input terminals. Twisted pair, shielded
cable is not required for binary input wiring.

Manual Cooling and Heating Enable

Cooling Enable

24 VAC must be applied to binary input MCB-BI3 to enable
cooling operation. If not, the unit Clg Status= parameter in the
System menu of the keypad/display indicates "Off Sw" and
cooling operation is unavailable. 24 VAC is applied to
MCB-BI3 when terminals 101 and 105 on the unit field
terminal block (TB2) are made; either with a factory installed
jumper wire or a field supplied switch. Refer to the unit wiring
diagrams or Figure 16 on page 39 (DAC units) or Figure 17 on
page 40 (SCC units) for wiring termination details.

Heating Enable

24 VAC must be applied to binary input MCB-BI4 to enable
heating operation. If not, the Htg Status= parameter in the
System menu of the keypad/display indicates "Off Sw" and
heating operation is unavailable. 24 VAC is applied to
MCB-BI4 when terminals 101 and 106 on the field terminal
block (TB2) are made; either with a factory installed jumper
wire or field supplied switch. Refer to the unit wiring diagrams
or Figure 16 on page 38 (DAC units) or Figure 17 on page 41
(SCC units) for wiring termination details.
Daikin IM 696-4

Manual Unit Enable

Unit operation is manually disabled when 24 VAC is applied to
binary input MCB-BI2. The UnitStatus= parameter in the
System menu of the keypad/display indicates "Off Sw" and the
unit will not operate. This occurs when a field supplied and
installed switch across terminals 101 and 104 on the field
terminal block (TB2) is in the on or closed position. Refer to
the unit wiring diagrams or Figure 16 on page 39 (DAC units)
or Figure 17 on page 40 (SCC units) for wiring termination
details.
If not disabled by this method, the unit is enabled to run when
placed in the occupied mode. For details regarding occupied/
unoccupied operation refer to the "Auto/Manual Operation"
section of the appropriate program-specific operation manual
(refer to Table 1 on page 1).

External Time Clock or Tenant Override

There are several methods of switching the rooftop unit
between occupied and unoccupied operation. It can be done by
the controller internal schedule, a network schedule, an
external time clock, or a tenant override switch.
If the internal schedule or a network schedule is used, field
wiring is not required.
An external time clock or a tenant override switch can be used
by installing a set of dry contacts across terminals 101 and 102
on the field terminal block (TB2). When these contacts close,
24 VAC is applied to binary input MCB-BI1, overriding any
internal or network schedule and placing the unit into occupied
operation (provided the unit is not manually disabled). When
the contacts open (24 VAC is removed from MCB-BI1) the
unit acts according to the controller internal time schedule or a
network schedule. Refer to the unit wiring diagrams or
Figure 16 on page 39 (DAC units) or Figure 17 on page 40
(SCC units) for wiring termination details.
For information on setting internal and network controller
schedules, refer to the "Scheduling" section in the applicable
operation manual (refer to Table 1 on page 1).
Field Wiring
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