Trane CNT-SVX07C-EN, Zone Controller, N512 AI4 Universal 4-20 mA, Configuration Measurement range

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Analog inputs

Economizing (free cooling) is a function whereby outdoor air is used as a source of cooling before hydronic or DX cooling is used. The Tracer ZN521 uses the outdoor air temperature value to determine whether economiz- ing is feasible. Economizing is not possible without a valid outdoor air temperature. (For more information, see “Economizing (free cooling)” on page 45.)

The outdoor air temperature value is also used for the freeze avoidance function. This function is used for low-coil-temperature protection when the fan is off. The controller enters the freeze avoidance mode when the outdoor air temperature is below the freeze avoidance setpoint (config- urable using the Rover service tool). (For more information, see “Freeze avoidance” on page 50.)

If AI3 is configured as a generic temperature input, it can be monitored by a BAS. The controller receives the temperature as a resistance signal from a 10 kΩ thermistor wired to analog input AI3. The generic tempera- ture input can be used with any Trane 10 kΩ thermistor. The thermistor can be placed in any location and has no effect on the operation of the con- troller. The controller will generate a Generic Temperature Failure diag- nostic if the input becomes invalid or goes out of range.

Note:

AI3 is not polarity sensitive; you can connect either terminal to either sensor lead.

AI4: Universal 4–20 mA

The AI4 analog input can be configured in one of the three ways shown in Table 5.

Table 5. AI4 configuration options and associated measurement ranges

Configuration	Measurement range

Generic 4–20 mA input	0–100%
	(4 mA=0%; 20 mA=100%)

CO2 measurement	0–2000 ppm
	(4 mA=0 ppm; 20 mA=2000 ppm)

Relative humidity (RH) measurement	0–100%
	(4 mA=0% RH; 20 mA=100% RH)

If this input is not needed for an application, configure it as Not Used. This will disable the generation of diagnostics.

Note:

AI4 is polarity sensitive.

For the generic input configuration, a 4–20 mA sensor must be hard- wired to the AI4 terminal. (Wiring is dependent on the specific applica- tion.) The sensor communicates a value of 0–100% to the BAS. This con- figuration has no direct effect on Tracer ZN521 operation. If a valid value

CNT-SVX07C-EN

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Contents Installation and Operation Tracer ZN521 Zone Controller Page CNT-SVX07C-EN April CNT-SVX07C-EN Tracer ZN521 Zone Controller Installation and Operation CNT-SVX07C-EN Contents Sequence of operations Status indicators for operation and communication Troubleshooting Index Product description Overview and specificationsClearances DimensionsStorage environment Plastic-cover model dimensions and clearances Additional components Agency listing/complianceDamper actuators Tracer zone temperature sensor optionsZone humidity sensor CO2 sensorOverview and specifications AC-power wiring Input/output terminal wiringGeneral wiring information Communication-link wiring and addressing General wiring information Operating environment requirements Location recommendationsMounting the Tracer ZN521 zone controller Mounting recommendationsApplication SpeedfanMultiple Dehumidification Typical applications for the Tracer ZN521 zone controllerControlValve Economizing HeatElectricBinary inputs BI1 Low-coil-temperature detectionBI2 Condensate overflow Binary inputsBI4 Fan status BI3 Occupancy or generic binary inputAnalog inputs ZN Zone temperatureGND Ground terminals Analog inputsSET Local setpoint FAN Fan mode inputAI1 Entering water temperature AI3 Outdoor air temperature or generic temperature AI2 Discharge air temperatureAI4 Universal 4-20 mA AI4 configuration options and associated measurement rangesConfiguration Measurement range AI4 terminal wiring CO2 measurement Generic binary output Binary outputsBinary output functions Binary output FunctionsOverriding binary outputs Wiring requirements and optionsRequired controller inputs for proper operation Function Input source For more information SeeTwo-pipe hydronic-cooling unit Two-pipe hydronic-heating unit Two-pipe hydronic heating/cooling unit with auto changeover Four-pipe hydronic heating/cooling unit Four-pipe heating/cooling unit with auto changeover Two-pipe heating unit with DX cooling Electric heat unit with DX cooling Electric heat unit Two-pipe heating unit with face-and-bypass damper Two-pipe heating/cooling unit with face-and-bypass damper Four-pipe heating/cooling unit with face-and-bypass damper Input/output functions and wiring for typical applications Random start Power-up sequenceUnoccupied mode Occupied modeOccupied standby mode Occupancy modesTimed override control Occupied bypass modeSimplified zone control Zone temperature controlCascade zone control Discharge air tempering Heating or cooling modeMorning warm-up Morning cool-downFan operation Entering water temperature sampling functionExhaust control Exhaust controlModulating valve operation Valve operationModulating valve calibration Valve control optionsTwo-position valve operation Modulating outdoor/return air dampersIsolation-valve operation Two-pipe operationModulating outdoor air damper position Economizing free cooling Ashrae Cycle 1 conformanceAshrae Cycle 2 conformance Face-and-bypass damper operation Two-position control of a modulating outdoor air damperDX cooling operation Face-and-bypass, isolation-valve operationDehumidification Electric heat operationBaseboard heat operation Unit protection strategies Peer-to-peer communicationLow-coil-temperature protection Smart resetFan off delay Condensate overflowFreeze avoidance Filter-maintenance timerFreeze protection discharge air temperature low limit Tracer ZN521 zone controller circuit board Test buttonManual output test Output For nonClose damper, air Outdoor Open damper, air Outdoor BOP1 BOP2 BOP3 BOP4 BOP5 BOP6 BOP7 BOP8 BOP9 Step ResultRed LED Service indicator Service pin buttonInterpreting LEDs LED activity ExplanationYellow LED Communications indicator Green LED Status indicatorTypes of diagnostics DiagnosticsDiagnostics Table of diagnosticsDiagnostic Probable cause Consequences Type Fan unaffectedPosition Valved unaffectedDamper unaffected Status indicators for operation and communication Probable cause Explanation Fan does not energizeValves remain closed TroubleshootingDX or electric heat does not energize Valves remain openOutdoor air damper remains open Outdoor air damper remains closedOutdoor air damper remains open Troubleshooting Numerics IndexIndex Index Index Page Trane