Model 292T Feature Enhanced Two Channel Digital Inductive Loop Vehicle Detector with Timing Exceeds NEMA TS 2 Specification

• Self-tuning and complete environmental tracking.
• Two detector channels in a single unit
• Two selectable output modes per channel:
• Presence, normal hold time
• Pulse
• Front panel pushbuttons and a front panel alphanumeric LED display permits menu-driven programming of the following functions for each channel:
• Enable ON/OFF
• Loop frequency
• Sensitivity
• Output modes
• Delay timing
• Extend timing
• LED display indicates individual channel status states as defined by NEMA TS 2 when not being used for programming
• External status outputs provide individual channel status states as defined by NEMA TS 2
• Failsafe output for each detector channel
• Eight levels of sensitivity per channel
• Four loop frequencies per channel
• Detector can be assigned one of up to eight addresses
• Provision for communicating digitally with the detector
• Loops are sequentially scanned to minimize crosstalk
• High intensity red LED indicators to display detection (call) for each channel
• Two front panel pushbuttons reset both channels
• Complete low power CMOS digital design
• Operates on a single DC power supply
• Transformer isolation for loops
• Front panel width is 1.12 inches (2.84 cm)

Specifications

Self-Tuning: Operational within one second after application of power or after a reset command. 30 seconds of operation is required before full presence is possible.

Environmental and Drift Tracking: Fully self-compensating for environmental changes and component drift over full temperature range and entire loop inductance range.

Loop Inductance Range: 20 - 2500 microhenries with Q factor of 5 or greater.

Loop Feeder Length: Up to 5000 feet (1524 m.) maximum with proper feeder cable and appropriate loops.

Loop Input: Transformer isolated.

Loop Frequency: Four selectable frequencies (normally in the range of 20 - 50 kilohertz) are provided for each channel.

Lightning Protection: The detector can tolerate, without damage, a 10 microfarad capacitor charged to 2,000 volts to be discharged into the loop terminals or a 10 microfarad capacitor charged to 2,000 volts discharged between either loop terminal and earth ground.

External Reset: Switch closure between D.C. Common (pin A) and the reset line (pin C) for 15 microseconds or longer will reset both detector channels.

Manual Reset:

• Both channels of the detector may be manually reset by removing power momentarily or by pushing the front panel INC and DEC buttons together.
• An individual channel may be manually reset by momentarily changing the sensitivity for that channel, changing frequency.

Sequential Scanning: The two loops are alternately turned ON and OFF to minimize crosstalk..

Response Time: Measured with same sensitivity level settings for both channels. 

Output Conditions Table: 

Sensitivity: Vehicle detection results from negative change in loop inductance (-delta L/L). Note that the detector channel is reset automatically whenever the sensitivity level is changed. 

Detect Indicators Operation: High intensity red light emitting diodes (LED) indicate a call output for each channel.

Modes:

• PRES: Presence mode with a hold time of 4 minutes minimum (regardless of vehicle size) and typically 20 to 30 minutes for a car. May be conditioned with delay and extend timing.
• PUL: In the pulse mode, each vehicle generates a pulse output of 125±25 milliseconds. Should a vehicle remain over the loop for 2 seconds or longer, the detector will tune out the vehicle such that the remainder of the loop zone detects subsequent vehicles after 2 seconds. When the vehicle leaves the loop, the detector resumes full sensitivity 0.75 seconds. May be conditioned with delay and extend timing.

Call Delay Time: Programmable from 0-64 seconds in one second steps.

Call Delay Inhibit Mode: Switch closure (1 volt maximum) between delay inhibit line (ch. 1 - pin 1, ch. 2 - pin 2) and D.C. Common inhibits delay time function for that channel.

Call Extension Time: Programmable from 0-25 seconds in 0.1 second steps.

Call Output Circuit Rating: Darlington transistor optically isolated from each channel output; 36 VDC maximum collector to emitter; 50 milliamps maximum collector current, The transistor saturation level is 1.2 VDC maximum. The output transistor is protected with by a 36 volt transorb connected across the emitter and collector.

Status Output Circuit Rating: An open-drain FET solid state output, with source connected to D.C. common, provides an output for each channel. A 36 volt transorb is connected across the source and drain for transient protection.

Status Output Format: Status output conforms to NEMA TS 2. Refer to operator’s manual.

Programming Capability: The following functions can be programmed from the front panel for each channel:

• The channel can be enabled or disabled.
• Sensitivity level
• Output mode
• The initial frequency
• Delay timing
• Extension timing

Alpha-Numeric Display: A front panel 0.180 inch four digit LED display provides dual functions:

• During programming mode, provides the various steps in the programming menu.
• When not in programming mode, displays the operating status of both channels.

Programming Pushbuttons: Pressing any of the buttons, except EXIT, during normal operation will open the program menu.

• SET: Enters selected menu subheading or attribute into program.
• INC (Increase) or DEC (Decrease): Allows scrolling through to desired subheading or attribute.
• EXIT: Terminates the program and returns the detector to normal operation.

Detector Address Capability: Three external address pins (pins 6, 10, and 15) provide the capability of activating the detector address feature and provide up to eight hard-wired addresses.

Data Receive/Transmit Provisions: External input and output lines provide a means of communicating with the detector to set and read detector parameters. Protocol presently being defined by NEMA Standards Committee.

Operating Power: 10.8 VDC to 26.5 VDC, 80 milliamps maximum.

Operating Temperature: -40°F to +180°F (-40°C to +82°C).

Size: 4.5" H x 6.875" L x 1.12" W (11.4 x 12.5 x 11.4 cm). Edge card connector is centered on the 4.5" (11.4 cm) edge.

Weight: 5 ounces (141.7 g).

Connector: 2 x 22-pin edge card connector with 0.1.56 inch (4 mm) contact centers. Key slots are located between B and C, E and F, M and N.

Pin Assignments: (P1)

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