Transmitter-Outside

Supported Applications

The ACI Outside Air Series is a family of single-point outdoor temperature sensors and transmitters that report ambient air temperature to a building automation system (BAS) or controller. Each transmitter provides a two-wire, 4-20 mA loop-powered output with an optional 3-Wire voltage output of 1-5 VDC or 2-10 VDC, so outdoor conditions can drive economizer, reset and freeze-protection strategies.

The units are designed to be mounted out of direct sunlight on the North side of a building or under an eave or intake hood, and connect through 1/2" NPT threaded hubs. A ruggedized, epoxy-coated "POT" (potted) option is available for extreme environments or where added moisture protection is needed. Housings use weatherable materials including PC/ASA plastic with a UV protectant.

Operating Conditions & Performance

The sensing element is a platinum RTD with a positive temperature coefficient (PTC) and a single sensing point conforming to DIN EN 60751 (IEC 751), with a tolerance of ±0.06% Class A. Sensor resistance at 0°C (32°F) is 100 Ω nominal on the A/TT100 and A/TTM100 (Brown/Brown leads) or 1 KΩ nominal on the A/TT1K and A/TTM1K (Black/Black leads). Response time is 8 Seconds nominal at a 63% step change, and the sensor operating range is -40 to 71 °C (-40 to 160 °F).

Transmitters are powered from an unregulated or regulated +8.5 to 32 VDC supply (reverse-polarity protected) drawing 25 mA minimum. Maximum load resistance tracks the supply: a 250 Ω load needs +13.5 to 32 VDC and a 500 Ω load needs +18.5 to 32 VDC. Wiring lands on polarity-sensitive screw terminal blocks sized for 16 AWG to 26 AWG conductors.

Calibrated accuracy is +/- 0.04%/°F for temperature spans under 100°F (38°C) and +/- 0.02%/°F for spans over 100°F (38°C), with the calibrated span selectable from a minimum of 50°F (28°C) up to a maximum of 300°F (148°C). Transmitters are calibrated at 71 °F (22 °C) nominal and operate over -40°F to 185°F (-40 to 85°C), storing at -40 to 71 °C (-40 to 160 °F) and tolerating 0 to 90% non-condensing humidity.

Configuration Options

The lineup differs first by sensing element: the A/TT100 and matched A/TTM100 use the 100 Ω platinum element, while the A/TT1K and matched A/TTM1K use the 1 KΩ element. Matched (TTM) parts are supplied with a defined calibrated span, and their default NIST certificate covers 3 Point NIST at 20%, 50% and 80% of span, upgradeable to a 5 Point NIST at 20%, 35%, 50%, 65% and 80% of span.

Output type is a second differentiator: current models provide 4-20 mA (2-Wire, loop powered) and voltage models provide 1-5 VDC or 2-10 VDC (3-Wires). The "POTTED" option adds a ruggedized epoxy coating for harsh outdoor exposure.

Enclosure choice sets rating, material and temperature limits. The PC/ASA Euro -EH housing with UV protectant is UL94-V0 rated for -40 to 88 °C (-40 to 190 °F); the Polystyrene -4X is UL94-V2, NEMA 4X (IP 66), rated for -40 to 70 °C (-40 to 158 °F); and the Aluminum bell-box -BB is NEMA 3R, UL94-V2, NEMA 4X (IP 66), rated for -40 to 121 °C (-40 to 250 °F).

Key Product Differences

Part numbers follow the pattern A/<SENSOR SERIES>-<MODEL SERIES>-O-<OUTPUT SIGNAL>-<ENCLOSURE>-<POTTED>-<CALIBRATED SPAN>, assembled from the sensor element, output signal and enclosure.

• Sensor / element: TT100 and TT1K standard elements; matched TTM100 and TTM1K elements with a defined calibrated span.
• Output signal: 4-20 mA (2-Wire, loop powered) current or 1-5 VDC or 2-10 VDC (3-Wires) voltage.
• Enclosure: PC/ASA Euro (-EH), Polystyrene NEMA 4X (-4X) and Aluminum bell box (-BB).
• Potted option: ruggedized epoxy-coated "-POTTED" build for extreme environments.

Representative catalog part numbers include A/TT100-O-1-EH, A/TT1K-O-4-4X, A/TTM100-O-4-BB and the ruggedized A/TT100-O-2-4X-POTTED. Matched TTM100 and TTM1K parts default to a 3 point NIST certificate; a 5 point certificate can be added under the NIST TTM CERT-5PT. option.