33
Table 9 – LEDs
The LEDs on the RTU--MP show the status of certain functions
If this LED is on... Status is...
Power The RTU MP has power
Rx The RTU MP is receiving data from the network segment
Tx The RTU MP is transmitting data over the network segment
DO# The digital output is active
The Run and Error LEDs indicate control module and network status
If Run LED shows...
And Error LED shows... Status is...
2 flashes per second Off Normal
2 flashes per second
2flashes,
alternating with Run LED
Five minute auto---restart delay after system error
2 flashes per second
3flashes,
then off
Control module has just been formatted
2 flashes per second
4flashes,
then pause
Two or more devices on this network have the
same ARC156 network address
2 flashes per second On
Exec halted after frequent system errors or
control programs halted
5 flashes per second On Exec start---up aborted, Boot is running
5 flashes per second Off Firmware transfer in progress, Boot is running
7 flashes per second
7 flashes per second, alternating with
Run LED
Ten second recovery period after brownout
14 flashes per second
14 flashes per second,
alternating with Run LED
Brownout
On On
Failure. Try the follo wing solutions:
S Turn the RTU ---MP off, then on.
S F o r m a t t h e R T U --- M P.
S Download memory to the RTU---MP.
S Replace the RTU---MP.
NOTE: Refer to Form 48--50H--T--2T for complete
configuration of RTU--MP, operating sequences and
troubleshooting information. Refer to RTU--MP 3rd Party
Integration Guide for details on configuration and
troubleshooting of connected networks. Have a copy of
these manuals available at unit start--up.
SMOKE DETECTORS
Smoke dete ctors are ava ilable as factory--installe d opt ions
on 50T CQ models. Smoke detectors may be specified for
Supply Air only or for Return Air without or with
econom izer or in c ombination of Supply Air and Return
Air. Return Air smoke detectors are arranged for ve rtical
return configurations only. All compone nts necessary for
operation are factory--provided and m ounted. The unit is
factory--configured for immediate smoke detector
shutdown operation; additional wiring or m odifications to
unit terminal board may be necessary to complete the unit
and smoke detector configuration to me et project
requirements.
Units equipped with factory--optional Return Air smoke
dete ctors require a reloca tion of the sensor module at unit
installation. See “Completing Installation of Return Air
Smoke Sensor:” on page 35 for details.
System
The smoke det ector system consists of a four--wire
controller and one or two sensors. Its pri mary function is
to shut down the rooftop unit in order to prevent smoke
from circul ating throughout the building. It is not to be
used as a life saving device.
Controller
The controller (see Fig. 58) includes a controller housing,
a printed circuit board, and a clear plastic cover. The
controller can be connected to one or two compa tible duct
smoke sensors. The clea r pla stic cove r is secured to the
housing with a single captive screw for easy access to the
wiring terminals. The controller has three LEDs (for
Power, Trouble and Alarm) and a manual test/reset button
(on the cover face).
Sensor
The sensor (see Fig. 59) includes a plastic housing, a
printed circuit board, a clear plastic cover, a sampling
tube inlet and an exhaust tube. The sampling tube (whe n
used) and exhaust tube are attached during install ation.
The sampling tube varies in length depending on the size
of the rooftop unit. The clear plastic cover permits visual
inspections without having to disassembl e the sensor. The
cover attaches to the sensor housing using four captive
screws and forms an airti ght chamber around the sensing
electronics. Each sensor includes a harness with an RJ45
50TCQA
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