Products : Traffic

TD424N

The TD424N is a 4 channel microprocessor based vehicle detector, built to the requirements of the ANSI/NEMA Standard TS1, Part 15 (1989).
The TD424N is specifically designed as a traffic detector and has customised performance characteristics which make it ideal for road vehicle detection.
The function of the detector is to detect vehicle presence by means of an inductance change caused by the vehicle passing over a loop buried in the road surface.
The detector is designed for ease of installation and operating parameters can be individually set for each channel by DIP switches on the front panel of the unit and on the printed circuit card.
The TD424N provides outputs in the form of LED's on the faceplate and change-over relay contacts which are taken to the card edge-connector. A pair of LED's per channel indicate the presence or otherwise of a vehicle over the sensor loop and the fault status of the channel respectively. The relays are fail safe and will close on a vehicle detect or in the event of a power or loop failure.
The TD424N is a constructed to the NEMA standard with a dual 22 way direct mating gold-plated edge connector.
The TD424N may be utilised in a number of road vehicles applications which include vehicle detection for vehicle actuated (VA) control at junctions, speed measuring applications, vehicle counting, occupancy and queue applications in UTC. This product is suitable for all TS1 (1989) controller applications and Type 170 Rack configurations.

APPLICATIONS

· Urban intersection control
· Counting
· Occupancy measurement

Features of the TD424N

· Optimised Response Times:

Response times are optimised to facilitate the measurement of accurate vehicle presence data.

· Optimised Sensitivity:

Sensitivity levels are adjustable for each channel.
These have been carefully chosen for traffic control
applications allowing adjacent lane rejection and
elimination of interference.

· Adjustable Presence Time:

A range of four presence times is available and adjustable for each channel. This facilitates operation in passage mode, limited presence or for
queue detection.

· Loop Fault Monitor:

The TD424N provides fault output indications on an individual channel basis

· Sequential Polling:

Scanning techniques are employed to positively eliminate crosstalk between loops connected to the same detector module.

Using the TD424N in Intersection Control

Technical Data TD 424N


Self-tuning Range:	20– 1000 µH
Sensitivity:	Adjustable independently per channel between 0.02% L/L and 0.5% L/L. 3 positions on the 8 way switch allow the selection of seven sensivity levels in the above range. The eighth position of the sensitivity switch is "channel off"
Frequency:	Four step selectable on PCB 24khz - 150 khz (Frequency dependent on loop per channel)
Output Configuration:	One presence output per channel
Presence Time:	Four step adjustable on faceplate 3.5 seconds 8 minutes (Factory pre-set if switch 5 not fitted) 40 minutes Indefinite Presence - proportional to %L/L
Response Times:	Turn on 52mS ± 3.5 mS Run off 52mS ± 3.5 mS Recovery ± 80 mS
Fault Outputs:	Each channel of the detector is provided with a high intensity LED on the detector faceplate that is illuminated to indicate the presence of the fault condition.
Output Indications:	Each channel of the detector is provided with a high intensity LED on the detector faceplate that illuminates to indicate a detect output for the channel. The output indication is modified to indicate the operation of the delay/ extend timings as follows: Delay timer counting = Output LED flashes at 8 Hz rate Extend timer counting = Output LED flashes at 16 Hz rate.
Protection:	Solid state: Isolated current sink rated at 50 ma @ 50V DC outputs Loop inputs - gas discharge tube protection, isolation Transformer, and Zener diode clamping on loop inputs 24 V DC input - Reverse polarity diode and Tranzorb.
Power Requirements:	10-40 V DC and 100 ma Max
Output Relays:	Sealed relays rated at 1A @ 220 VAC Single change-over contact per output
Operating Temp Range:	-20°C to +85°C
Mechanical Details :	NEMA Standard 175mm x 114mm (excluding hand-pull) 25 mm wide
Faceplate:	(1 inch). Screened lettering on a silver metal front panel indicating switch and LED functions.
Connector:	2 x 22 terminal (double row) 0, 156 - inch contact spacing, Cinch Jones card edge connector. 50 -44A -30M, or equivalent.