Mesa Engineering ATRG2-MOD Field disturbance device for detecting presence and speed of passing vehicles User Manual
Mesa Engineering, Inc. Field disturbance device for detecting presence and speed of passing vehicles
User Manual
Mesa Engineering
G2 Vehicle Detection Module
User Manual
TABLE OF CONTENTS
1. Purpose
2. General Specifications
3. Installation
3.1 General Recommendations
3.2 Exposure Cautions
3.3 Co-Location Warnings
3.4 FCC Statement
3.5 Field Tune
4. Calibration
5. Interface
6. Data Format
6.1 Power Up Message
6.2 Measurement Message
6.3 ATR Reporting format Quick Reference
7. Command Guide
1.0 Purpose
The G-2 Vehicle detection module is a self contained Doppler radar sensor designed
for the purpose of detecting and counting vehicle passages with speed and length
data supplied. Suitable applications are traffic logging systems and speed
enforcement systems.
The system consists of a Gunn oscillator driven autodyne detected Doppler system
with a single horn lens antenna with a 4X15 degree response pattern suitable for
use in ATR traffic radar applications calibrated for a 22.5 degree traffic offset angle.
Base band signals from the transceiver are amplified and processed with digital
logic to produce a track for each dominant Doppler return received. Tracks are
analyzed for consistency duration and frequency offset to create an individual
output for each track, listing its speed, duration and overall reading quality.
Output and control are provided via an ASCII coded serial interface provided with a
full duplex rs485 or RS232 interface, for connection to external computing of
logging equipment.
2.0 General Specifications
Frequency 34.6 GHz +-100MHz
Transmitter power level -8dBm
Antenna Horn-Lens 30dBi gain
Supply voltage – current -connector
10.5-14.8 VDC 750mA max
Output
ASCII serial 115.2k Baud
RS232/DB9 or RS485/RJ-11
Mechanical
Rectangular chassis 8"x3"x10"deep
4x6-32 mounting screws
Microwave port 6.25"x2.75"
3.0 Installation
3.1 General Recommendations
Unit should be installed with antenna level horizontally, tilted down to meet the
roadway midway down its measurement range and at an offset angle of 22.5
degrees from the direction of traffic flow.
Unit should be 5-10 feet from the nearest lane.
The sensor should be placed far enough from intersections that vehicles traveling in
other directions should not cross into the beam.
The microwave port can be covered by an approved microwave transparent
window.
3.2 Exposure Cautions
Operating and maintenance personnel should maintain a separation of at least 20
cm from the port. Mounting should also preclude exposure to pedestrians or
drivers.
3.3 Co-Location Warnings
Additional radiators should not be co-located with the microwave aperture.
3.4 FCC Statement
This equipment has been tested and found to comply with the limits for a Class A
digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to
provide reasonable protection against harmful interference when the equipment is
operated in a commercial environment. This equipment generates, uses, and can
radiate radio frequency energy and, if not installed and used in accordance with the
instruction manual, may cause harmful interference to radio communications.
Operation of this equipment in a residential area is likely to cause harmful
interference in which case the user will be required to correct the interference at his
own expense.
Changes or modifications not expressly approved by Mesa Engineering could void
the user’s authority to operate this equipment.
3.5 Field Tune
Recommended field tune command sequence.
This command is performed with a microwave absorbing foam block securely in
front of the antenna horn. The Sequence adjusts the detector threshold for a
background noise trigger rate dependant on the sensitivity threshold setting.
Larger sensitivity settings have high noise trigger rates, hence higher signal
sensitivity.
Alignment should be performed anytime the sensor environment is changed, like
switching vehicles or reinstalling a fixed unit.
For directions on sending commands, see Command Guide section below.
TN02 -- set sensitivity threshold to 2
TA Threshold -> 02 -- Auto tune thresholds
........
04/0000/F7
........
03/0000/FA
........
02/0002/FB
........
01/0000/FC
4.0 Calibration
Unit operating frequency should be certified at least once per year and electronic
tuning fork test can be performed on starting and ending each deployment.
5.0 Interface
Power Molex 39-01-4031
Pin: 1 3
GND +12
Data 115.2 kBaud 8 bit, no parity, no handshake
RS232 9 Pin Sub-D Female
Pin: 2 3 5
Out In GND
RS485 RJ-11
Pin: 1 2 3 4 5 6
GND IN+ IN- Out- Out+ NC
6.0 Data Format
6.1 Power Up Message
Alignment ch4 -> ch1 => F7 FA FB FC
ATR g3 v3.0
FPGA revision 97 D9 1C
The power up message provides the current field tune alignment, firmware revision
level and the fpga revision level
6.2 Measurement Message
The measurement message is a 30 byte message followed by an optional variable
flag message terminated by cr-lf.
The following reference contains decoding information. One message is output for
each vehicle track observed by the sensor.
6.3 ATR Reporting Format Quick Reference
0000000000111111111122222222223333333333
0123456789012345678901234567890123456789
| | ||| | | | |
RE061 010 K+074 t 0000 00011D10 f
RE059 009 K+074 t 0000 0001054D f
RE059 009 K+074 t 0000 0001054D f
RE -Radar Event per earlier software
059 -The signal strength, BCD format
009 -The apparent vehicle length in meters, BCD format
K -Units of measure, Kph in this case, M if this is MPH
+ -The direction of travel, + is approaching the radar
074 -The vehicle speed, BCD format
T -The track termination mechanism, usually t, s, or r
0000-The track history standard deviation in HEX format
0001054D -The track duration in 8 usec units
"f" -Informational flags, multiple possibilities
These ARE VOID codes. If the flag field contains any one or more of these then do
not issue the citation:
g - LVLEN was zero in QC-final
c - Track history contains too few or too many data points
s - Track standard deviation was excessive
m - Excessive track data missing
e - Extraneous track data present
In the MFM logic, c, m, & e voids are grouped together into one statistic.
The track termination field is a fixed single character lower case alphabetic and follows
the speed field.
Its usage and meaning is unrelated to the flags field.
These codes occur after the speed and express the mechanism by which the target track
terminated. None of these are VOID codes.
t -Reflected signal fell below minimum threshold strength
r -Reflected signal reversed direction
s -Reflected signal centered to new different speed
7.0 Command Guide
Commands are an ASCII coded message terminated by a cr. Undefined command
strings get a ? cr-lf response.
Help
H cr causes a dump of available commands and their syntax/
Ax Analog channel lock
0-Float {default}, 1-DopA approach
2-DopB recede, 3-PhaA, 4-PhaB
Cx Calibrator function
0- terminate
1-4 Tuning Fork profile#
5-8 (151,75,38,19)Mph (243,123,60,30)Kmh Calibrator profile#
Dmx DebugTrace mode control
0-normal operation {default}, 1-sequential states, 2-packet values
TRACE state symbols: ! =squelch transition + =1 Meter marker
annnn =SQLbreak value p =arriving measure packet l =speedlock set
t =track timeout r =direction reversal z =short track abort
[ =track drop start ~ =drop timeout ] =drop normal w =wait state entered
Jxxyy Manual analog channel setting
xx = channel select
01-DopB{approach}, 02-DopA{recede}, 03-I, 04-Q
yy = channel sensitivity, FF=maximum, 00=minimum
L Force Watchdog activation
Q Compact information summary request
Rn Read CPLD channel n, 0 thru 6 inclusive
Wnyy Write CPLD register n with value yy
S Simulate Vehicle: S+v Approaching, S-v Receding
TNnn Set Analog alignment threshold to nn
TA perform verbose analog channel alignment
T? report current analog channel settings
U Emit ASCII U test pattern
Xn Microwave transceiver control
0-Standby, m-Mph, k-Kmh, s-Pulsed Mph, t-Pulsed Kmh
blank - Report current operating mode
Z RTI interrupt rate test pattern
If no command is received for two minutes after power up, the unit enters MPH
measurement mode and turns on the radar power.
Examples of common commands follow:
T? Alignment ch4 -> ch1 => F7 F7 F7 FC -- command displays current alignment
factors.
Q -- report quick status
RQ030097D91CF7F7F7FC
U -- send full baud square wave diagnostic
UUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUUU
UUUUUUUUUUUUUUUUUUUUUA
Xm -- turns radar on enables MPH scale factors
C5 -- electronic tuning fork test 1
RIp 151
C6 -- electronic tuning fork test 2
RIp 075
C7 -- electronic tuning fork test 3
RIp 038C8 -- electronic tuning fork test 4
RIp 019
S+v RE070 013 M+070 t 0002 0000D798 -- simulated speed reading
Xk -- turns radar on enabling KPH scale factors
C5 -- electronic tuning fork test 1
RIp 243
C6 -- electronic tuning fork test 2
RIp 122
C7 -- electronic tuning fork test 3
RIp 061
C8 -- electronic tuning fork test 4
RIp 031
X0 -- turns off radar system