Field Actuator Feedback - 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 equiva-
lent). Cable with 22 AWG conductors is sufficient.
CAUTION
Do not install this cable in the same conduit as
AC power wiring. Induced current and RFI from
AC wiring can interfere with the controls.
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 (T) position.
Detailed information regarding discharge air temperature
reset can be found in the "Discharge Set Point Reset" section
of the applicable operation manual (refer to Table 1 on
page 3).

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 con-
trol 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
IM710
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 equiva-
lent). Cable with 22 AWG conductors is sufficient.
CAUTION
Do not install this cable in the same conduit as
power wiring.
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
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 ter-
minals 91 and 92 on the terminal block (TB2). These termi-
nals 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.
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