AAON MODGAS-X, Техническое руководство

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16
MODGAS-X Technical Guide
INPUTS AND OUTPUTS
Inputs and Outputs
I/O Map
See Table 2, this page to reference the inputs and outputs that
are available on the MODGAS-X Module.
Analog Inputs
Reset Input (RST IN)
Used only in Stand-Alone Mode. The Discharge Temperature
Setpoint can be reset by supplying a 0-10 VDC signal to the
RST IN low voltage terminal block. This reset signal is optional
and need only be used if you require resetting of the discharge
air temperature.
Supply Air Temperature Sensor (SAT)
Used in Stand-Alone Mode and when MODGAS-X is connected
to a CAV/VAV or MUA Controller. The Supply Air Temperature
Sensor is the control source. This sensor has to be installed for the
unit to operate. The Supply Air Sensor is located in the discharge
air stream and monitors Discharge Air Temperature to maintain
the Discharge Air Temperature Setpoint.
Binary Inputs
Heat Enable Contact (HEAT EN)
This input is only required when the MODGAS-X is used in
Stand-Alone Mode. The Heat Enable Input is activated by a 24
VAC signal supplied from a building automation system to enable
the MODGAS-X. The MODGAS-X will not operate without 24
VAC being applied to this input terminal when used in a Stand-
Alone Mode. When the Heat Enable Signal is lost or turned off,
all stages deactivate immediately.
This enable input can be used in Communications Mode for
special circumstances. Heat Enable can be activated by either
communications or this enable input. Heat enable will be
deactivated when both signals from communications and the
enable input are turned off.
Analog Output
Gas Valve Output (VOUT)
Depending on the type of valve used, this output will supply
a 0-20 VDC or 0-10 VDC output signal for control of the
modulating gas valve. With a 0-20 VDC valve, the operation is
reverse acting, so high voltage means closed and low voltage
means open. With a 0-10 VDC valve, the operation is direct
acting.
WARNING:
For 0-20 VDC valves, the maximum number
that can be connected/configured is two. For
0-10 VDC valves, the maximum number
that be can connected/configured is eight.
Relay Outputs
FAN (RLY1) - Fan and Stage 1 Heat Modulating
When the MODGAS-X has heat enabled, this relay closes to
bring the induced draft blower on at high speed. The module will
activate the Low Speed Fan Relay to reduce the induced draft
blower speed as the gas valve modulates closed. This relay is
also used to enable Modulating Heat Valve 1.
LOW SPEED (RLY2) - Low Speed Fan
Depending on the gas valve position, this relay will close to
switch the induced draft blower to low speed. The module
automatically switches the blower to low speed as the gas valve
modulates closed in order to maintain the proper fuel-to-air ratio.
AUX 1 (RLY3) - Stage 2 Heat
(Fixed or Modulating)
If configured for two or more stages of heat, this relay would
enable the second stage of heat if the first modulating valve
cannot maintain the configured Supply Air Temperature Setpoint.
This stage and any additional stages of heat will stage up and
down as required to maintain the Supply Air Temperature
Setpoint. The Stage Up Delay default is three minutes. The Stage
Down Delay default is one minute.
Analog Inputs
1
(RST IN) Reset Signal
2 (SAT) Supply Temperature
3 (AUX AI) Not Used
Binary Inputs
1
(AUX BI) Not Used
2 (HEAT EN) Heat Enable
Analog Outputs (0-10 VDC)
1 (FAN) Fan and Stage 1 Heat (Modulating)
2 (LOW SPEED) Low Speed Fan
3 (AUX 1) Stage 2 Heat (Fixed or Modulating)
4 (AUX 2) Stage 3 Heat (Fixed or Modulating)
Table 2: MODGAS-X Inputs and Outputs