Field Actuator Feedback; Field 100% Oa Damper Actuator - McQuay MicroTech II Installation And Maintenance Manual

The external reset signal must be field-wired to the unit
using a twisted pair, shielded cable (Belden 8761 or
equivalent). Cable with 22 AWG conductors is sufficient.
Do not install this cable in the same conduit as power
wiring. Improper control will result.
Note: The analog input jumper associated with analog input
MCB-AI2 must be configured in the no-jumper (NJ-
VDC) position if the field signal is in the 0–10 VDC
range. The analog input dip-switch for this input then
must be in the ON (V) position. The jumper must be
configured in the current (2-MA) position if the field
signal is in the 0–20 mA range. The analog input dip-
switch for this input then must be in the "Off" (or T)
position.
Detailed information regarding discharge air temperature
reset can be found in the "Discharge Setpoint Reset" section
of the applicable operation manual (see Table 1 on page 1).

Field Actuator Feedback

When the MicroTech II controller is interfaced with a
field-supplied steam/hot water, airside economizer, or chilled
water valve actuator, a position feedback signal can be
field-wired from the actuator and input to the MCB. This
signal is not required for the steam/hot water and chilled
water control purposes but is required for 0–100% capacity
indication on the keypad or via a network interface. If the
signal is not supplied, the valve is controlled properly, but
associated capacity parameter will always indicate 0%. The
signal is required for the airside economizer control.
The external feedback signal must be field-wired to the unit
using a twisted pair, shielded cable (Belden 8761 or
equivalent). Cable with 22 AWG conductors is sufficient.
Do not install this cable in the same conduit as power
wiring. Improper control will result.
Field airside economizer damper actuator. When
interfaced with a field-supplied damper actuator, a damper
feedback signal in the form of a resistance that varies from 0
to 1000 ohms as the actuator strokes from 0 to 100% open
14
CAUTION
CAUTION
can be wired to terminals 65 and 66 on the terminal block
(TB2). These terminals are factory-wired to analog input
MCB-AI9. Refer to the unit wiring diagrams.
Note: The analog input jumper associated with MCB-AI9
must be set to the resistance (1-RTD) position. The
analog input dip switch associated with this input
must be set to the "Off" (or T) position.
Field steam valve actuator. When interfaced with a
field-supplied steam valve actuator, a valve feedback signal
in the form of a resistance that varies from 0 to 1000 ohms as
the actuator strokes from 0 to 100% open can be wired to
terminals 91 and 92 on the terminal block (TB2). These
terminals are factory-wired to analog input MCB-AI10.
Refer to the unit wiring diagrams.
Note: The analog input jumper associated with MCB-AI10
must be set to the resistance (1-RTD) position. The
analog input dip switch associated with this input
must be set to the "Off" (or T) position.

Field 100% OA Damper Actuator

When interfaced with a field-supplied damper actuator, wire
a damper feedback signal—in the form of resistance varying
from 0 to 1000 ohms as the actuator strokes from 0 to 100%
open—to terminals 65 and 66. On terminal block (TB2),
these terminals are factory wired to analog input MCB-AI9.
A normally closed contact along with a 1000 ohm resistor
between the economizer (MCB-AI9) position terminals can
be used instead of the 0–1000 ohm potentiometer to indicate
the outside damper is at least 50% open. When the normally
closed contact opens, the fan is allowed to start.
Note: The analog input jumper associated with MCB-AI9
must be set to resistance (1-RTD) position. The
analog input DIP switch associated with this input
must be set to the "Off" (or T) position.
641
9
AI9
9C 642
65
NC
1000
Ω
66
McQuay IM 710-1