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11. Shall include an EIA--485 protocol communication port, an access port for connection of either a computer or a
Bryant technician tool, an EIA--485 port for network communication to intelligent space sensors and displays, and
a port to connect an optional LonWorks plug--in communications card.
12. Shall have built--in support for Bryant technician tool.
13. Software upgrades will be accomplished by local download. Software upgrades through chip replacements are not
allowed.
14. Shall be shock resistant in all planes to 5G peak, 11ms during operation, and 100G peak, 11ms during storage.
15. Shall be vibration resistant in all planes to 1.5G @ 20--300 Hz.
16. Shall support a bus length of 4000 ft (1219m) max, 60 devices per 1000 ft (305m) section, and 1 RS--485 repeater
per 1000 ft (305m) sections.
23 09 23.13.B. RTU--MP -- Open protocol, direct digital controller:
1. Shall be ASHRAE 62--2001 compliant.
2. Shall accept 18--30VAC, 50--60Hz, and consumer 15VA or less power.
3. Shall have an operating temperature range from --40_F(--40_C) to 130_F(54_C), 10% -- 90% RH (non--condens-
ing).
4. Shall include built--in protocol for BACNET (MS/TP and PTP modes), Modbus (RTU and ASCII), Johnson N2
and LonWorks. LonWorks Echelon processor required for all Lon applications shall be contained in separate com-
munication board.
5. Shall allow access of up to 62 network variables (SNVT). Shall be compatible with all open controllers
6. Baud rate Controller shall be selectable using a dipswitch.
7. Shall have an LED display independently showing the status of serial communication, running, errors, power, all
digital outputs, and all analog inputs.
8. Shall accept the following inputs: space temperature, setpoint adjustment, outdoor air temperature, indoor air qu-
ality, outdoor air quality, compressor lock--out, fire shutdown, enthalpy switch, and fan status/filter status/ humid-
ity/ remote occupancy.
9. Shall provide the following outputs: economizer, fan, cooling stage 1, cooling stage 2, heat stage 1, heat stage 2,
heat stage 3/ exhaust/ reversing valve.
10. Shall have built--in surge protection circuitry through solid state polyswitches. Polyswitches shall be used on in-
coming power and network connections. Polyswitches will return to normal when the “trip” condition clears.
11. Shall have a battery back--up capable of a minimum of 10,000 hours of data and time clock retention during power
outages.
12. Shall have built--in support for Bryant technician tool.
13. Shall include an EIA--485 protocol communication port, an access port for connection of either a computer or a
Bryant technician tool, an EIA--485 port for network communication to intelligent space sensors and displays, and
a port to connect an optional LonWorks communications card.
14. Software upgrades will be accomplished by either local or remote download. No software upgrades through chip
replacements are allowed.
23 09 33 Electric and Electronic Control System for HVAC
23 09 33.13 Decentralized, Rooftop Units:
23 09 33.13.A. General:
1. Shall be complete with self--contained low--voltage control circuit protected by a resettable circuit breaker on the
24--v transformer side. Transformer shall have 75VA capability.
2. Shall utilize color--coded wiring.
3. Shall include a central control terminal board to conveniently and safely provide connection points for vital con-
trol functions such as: smoke detectors, phase monitor, gas controller, economizer, thermostat, DDC control op-
tions, and low and high pressure switches.
4. The heat exchanger shall be controlled by an integrated gas controller (IGC) microprocessor. See heat exchanger
section of this specification.
5. Unit shall include a minimum of one 8--pin screw terminal connection board for connection of control wiring.
23 09 33.23.B. Safeties:
1. Compressor over--temperature, over--current. High internal pressure differential.
2. Low--pressure switch.
a. Units with 2 compressors shall have different sized connectors for the circuit 1 and circuit 2 low and high pres-
sure switches. They shall physically prevent the cross--wiring of the safety switches between circuits 1 and 2.
b. Low pressure switch shall use different color wire than the high pressure switch. The purpose is to assist the
installer and service technician to correctly wire and or troubleshoot the rooftop unit.
581J