Reno A & E S-1201 Operations Manual
Model S-1201 Series
MODEL S-1201
Loop Detector
Operations Manual
Two Channel Menu Driven Programmable Inductive Loop
Detector
Built-in Loop Analyzer for Each Channel
This manual contains technical in formation for the
Model S-1201 Loop Detector
pn 889-1909-00 Revision: April 2020
THE FOLLOWING PRODUCT WAS DESIGNED, INSPECTED , TESTED AND
MANUFACTURED IN THE USA BY EBERLE DESIGN, INC. IN PHOENIX, ARIZONA.
INFORMATION CONTAINED HEREIN IS PROPR IETARY TECHNICAL INFORMATION OF
EBERLE DESIGN, INC. PUBLICATION, REPRODUCTION OR USE IN WHOLE OR PART IS
NOT PERMITTED EXCEPT UNDER TERMS AGREED UPON IN WRITING. ALL
REGISTERED TRADEMARKS OF EBERLE DESIGN INC. ARE UNDER
IT IS AN EBERLE DESIGN, INC. RECOMMENDATION THAT EACH UNIT BE TESTED
AT LEAST ANNUALLY TO ENSURE COMPLIANCE WITH FACTO RY
SPECIFICATIONS AND MEETS PROPER OPERATIONAL STANDARDS. THE
RESULTS OF THIS TESTING WILL BE DOCUMENTED.
© COPYRIGHT
MAINTENANCE NOTE
Model S-1201 Operations Manual
Table of Contents
Section 1 General Description .......................................................................................................... 1
Section 2 General Characteristics .................................................................................................... 2
2.1 Loop Frequency ..................................................................................................................... 2
2.2 Sensitivity .............................................................................................................................. 2
2.3 Presence / Pulse ..................................................................................................................... 2
2.4 Call Delay .............................................................................................................................. 2
2.5 Call Exte ns ion ........................................................................................................................ 2
2.6 Max Presence Timer .............................................................................................................. 2
2.7 End-Of-Green (EOG) ............................................................................................................. 3
2.8 Detector ID ............................................................................................................................ 3
2.9 Option 1: Loop Inductance Display ....................................................................................... 3
2.10 Option 2: Loop Inductance -∆L/ L Display ........................................................................... 3
2.11 Option 3: Call Ext ension Control ......................................................................................... 3
2.12 Option 4: Noise Filter Disable ............................................................................................. 3
2.13 Option 5: Phase Green Loop Compensation ........................................................................ 4
2.14 Option 6: Vehicle Counting Display .................................................................................... 4
2.15 Option 7: Vehicle Counting Loop Configuration ................................................................. 4
2.16 Option 9: Third Car Passage ................................................................................................ 5
2.17 Option 10: Direc tional Logic ............................................................................................... 5
2.18 Option 11, Audib le Det ect Signal ........................................................................................ 6
2.19 Option 12: Detector Disconnect ........................................................................................... 6
Section 3 Specifications ..................................................................................................................... 8
3.1 Physical .................................................................................................................................. 8
3.2 Electrical ................................................................................................................................ 8
3.3 Operational ............................................................................................................................ 8
3.4 Table: Sensitivity, -∆L/L, and Response Time ....................................................................... 9
3.5 Table: Default Settings ........................................................................................................... 9
3.6 Table: Pin Assignments ....................................................................................................... 10
Section 4 User Interface .................................................................................................................. 11
Channel Select Pushb utton ................................................................................................. 11
Section 5 Installation and Set-Up ................................................................................................... 12
5.1 Program Mode Display Screens ........................................................................................... 12
5.2 Normal Mode Display Screens ............................................................................................ 16
5.3 Detector ID / Communication Proocol ................................................................................. 19
5.4 Loop Fail Indications ........................................................................................................... 20
5.5 Setting Sensitivity using the Bargraph ................................................................................. 20
5.6 Setting Sensitivity for Motorcycle Detectio n using the Bargraph ........................................ 22
5.7 Full Restore to Factory Default Settings .............................................................................. 22
5.8 Display Test ......................................................................................................................... 22
Section 6 System Schematic ............................................................................................................ 23
Section 7 Block Diagram ................................................................................................................ 24
Section 8 The o ry of Operation ....................................................................................................... 25
Section 9 Maintenance and Troubleshooting ................................................................................ 26
9.1 Troubleshooting Power Problems ........................................................................................ 26
9.2 Troubleshooting Initialization Problems .............................................................................. 26
9.3 Troubleshooting Loop Fail Problems ................................................................................... 27
9.4 Troubleshooting Intermittent Loop Fail Problems ............................................................... 28
9.5 Troubleshooting Intermittent Detector Lock-Ups ................................................................ 28
9.6 Troubleshooting Delay Problems ......................................................................................... 29
9.7 Things to Know About Loops .............................................................................................. 29
Section 1 General Description
This Operation Manual was written for people installing, operat ing, and maintaining Reno A & E Model S-1201
inductive loop vehicle detectors. Designed to be used in freeway entrance and exit ramp monitoring applicat ions,
the Model S-1201 is a two channel, shelf mount type, inductive loop vehicle detector that meets or exceed NEMA
Standards TS 1-1989. A rear mounted DB-9 serial connector can be used to provide a means of communication
with other related equipment.
The Model S-1201 incorporates a microcontroller that monitors and processes signals from two separate loop /
lead-in circuits and two Phase Green Inputs. The microcontroller uses these inputs to determine how to control the
detector outputs. A Liquid Crystal Display (LCD), two light emitting diodes (LEDs), and four front panel
pushbuttons are used to display and program all detector funct ions. Several diagnostic modes are available to aid
technicians and service personnel in troubleshooting detection problems.
The use of a LCD is what distinguishes this detector from that of other manufacturers. It allows more informat ion,
never before available, to be displayed to the user during normal operation of the detector. T he LCD makes it easy
to view and adjust all programmable detector opt ions and settings. It is no longer necessary to check o r change
detector settings with DIP sw itches. An eight-segment bargraph at the top of the LCD c an be used to provide a
graphical representation of the relative change of inductance as seen by the detecto r at the current sensitivity level.
The bargraph automatically takes into account loop size, loop inductance, number of loops, number of turns, loop
geometry, lead-in length, etc. The bargraph functions as a sliding scale that relates to the programmed Sensitivity
Level. The first (left-most) bargraph segment represents the minimum inductance change necessary for the
detector to output a call at the currently selected sensitivity level. Larger inductance changes will indicate more
segments. Each additional segment indicates that the next sensitivity level has also been met or exceeded. When
used in th is manner, the bargraph provides an indication of whether the sensitivity is set too high or too low,
facilitating the ideal setting of the se ns itivity level.
All programmed settings are stored in non-volatile memory and can only be changed by programming new
settings. Loss of power or a de tector reset will not change any of t he programmed settings. If a loop failure
occurs, the LCD will display the type of lo op failure as L lo (for -25% change or shorted loop conditions) or L hi
(for +25% change or open loop c onditions). Each loop failure is co unted and accumulated in the Loop Failure
Memory. The number of loop failures since the last detector reset or power interruption is very useful information
to have available during analysis of intermittent loop operation.
The Model S-1201 Series detector is a scanning detector. The scanning operation sequentially activates the ON
and OFF cycle of each channel’s oscillator. Since only one channel’s loop(s) is (are) active at a given time,
crosstalk between adjacent loops connected to the same scanning detector is minimized. The Model S-1201
Series’ unique scanning process a lso disconnects the capac itors and dampens t he oscillator during t he OFF cycle.
This eliminates oscillatio n past the O FF point ( ringing or decay) e very time the loop circuit is scanned, w hich can
result in crosstalk. When operating in the Program Mode, the Model S-1201 S eries disp lays t he rea l time loop
frequency reading for each channel. The eight frequency settings can be incremented or decremented to provide
precise frequency readings, removing any guesswork when cha nging frequency settings to eliminate crosstalk.
NOTE: Adjacent loops connected to different c hannels of a non-scanning dete ctor or d ifferent scanning dete ctors
should be set to different frequencies with maximum separation.
The Reno A & E Model S-1201 Series utiliz es the first major innovation in inductive loop detectors since the
introduction of digital detecto rs. The programming of all of the detector’s para meters with four normally open
pushbutton switches not o nly simplifies setup by removing binary coded DIP s witches, but also increases the
reliability of the detector by eliminating the dependence on switch contacts during normal operation. The detailed
descriptions displayed on the LCD eliminate the interpretation of numerous LED flash rates to determine the
detector status. In addition, the Model S-1201 offers t he versatility of softwa re control. Special funct ions are
possible with a simple change of the s ocket-mounted microprocessor. Special functions are defined as unique
options (e.g. Option 6, Opt ion 12, etc.). Spe cial option functio ns are activated thro ugh the use o f the LCD menu
option programming.
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Section 2 General Characteristics
2.1 LOOP FREQUENCY
There are eight (8) selectable loop frequency settings (normally in t he range of 20 to 100 k ilohertz) per channel.
The actual loop operating frequency is a function of the loop / lead-in network and the components of the loop
oscillator circuit. The d igital display of the actual loop operating frequency for each setting makes it easy to
quickly identify and eliminate crossta lk in the most difficult to configure intersections. The frequency display is
typica lly very st able when t he loop is va cant and ve hicles ar e not passi ng nearby the loops. If the reading is
varyin g by more than ±1 in the last digit, this is an indication of possible crossta lk betwee n loops.
2.2 SENSITIVITY
There are nine (9) selectable sensitivity levels per channel, plus Continuous-Call and Channel-Off. The se nsitivit y
levels are designed so that a one level increase actually doubles the sensitivity and a one level decrease halves the
sensitivity. A unique bargraph d isplayed on t he LCD makes it eas y to quickly set sensitivity at t he ideal level for
any loop / lead-in network configuration. (See Section 3.4 for actual detectio n levels at each sensitivity level.)
C
ONTINUOUS-CALL: Whe n se t t o t he Co nt in uo us -Call state , the c hannel ou tput is co ntinuous ly in t he Call state
regardless of the presence or absence of vehicles over the loop. The loop osc illator is disabled when in the
Continuous-Call state. T his state is indicated b y CALL flashing on the LCD. This option is selected from the
Sensit ivity men u in Progra m Mode and is useful fo r checkin g controlle r respons e and other troubleshooting
activities.
C
HANNEL-OFF: When s et to the Channel-O ff state, the channel output is cont inuously in the No Call state
regardless of the presence or absence of vehicles over the loop. The loop oscillator is disabled when in the
Channel-Off State. This sta te is indicated by OFF flashing on t he LCD. This option is selected from the
Sensitivity menu in Program Mode and is useful for checking co ntroller response and other troubleshooting
activities.
2.3 PRESENCE / PULSE
One of t wo mutuall y exclusive modes of operation for each channel is ava ilable. Presence or Pulse mode is
toggled by momentarily pressing e ither the (UP) or (DOWN) button.
P
RESENCE MODE: Provides a call hold time of at least four minutes (regardless of vehicle size) and typically one
to three hours for an automobile or truck.
P
ULSE MODE: An output Pulse of 125 ±10 milliseconds duration is generated for each vehicle entering the loop
detection zone. Each detected vehicle is insta ntly tuned out if it remains in the loo p detect ion z one lon ger t ha n
two seconds. This enables detection of subsequent vehicles entering the loop detection zone. After each vehicle
leaves the loop detection zone, the cha nnel resumes full sensitivity within 0.5 seconds.
2.4 CALL DELAY
Each channel’s Call Delay is adjustab le fro m 0 to 255 se conds in one second steps. Call Delay time starts coun ting
down when a vehicle enters the loop detection zo ne. The remaining Ca ll Delay time i s continuous ly displayed on
the LCD . W he ne ver a P has e Gr ee n I np ut ( C all D e la y Ove r rid e) si gna l ( pi n J o f t he M S co nne ct or of c ha nne l 1 or
2) is active, the Call Delay func tion for the channel is aborted and the Call Delay time is forced to zero.
2.5 CALL EXTENSION
Each channel’s Call Extension is adjustable from 0 to 25.5 seconds in 0.1 steps. Extension time starts counting
down when the last vehicle clears the loop detection zone. The remaining Call Extension time is continuously
displa ye d o n the LCD . Any ve hic le ent er in g t he lo op det ec t io n zo ne d ur in g the Ca l l Ext ens io n t i me p er iod causes
the channel to return to the Detect state, and later, when the last vehicle clears the loop detection zone, the full Call
Extension time starts counting dow n again. (See Option 3, Call Extension Control, for an a lternate mode of
operation for Call Extension.)
2.6 MAX PRESENCE TIMER
When activated, each channel’s Max Presence timer is adjustable from 1 to 999 seconds in one-second steps. A
setting of OFF turns the Max Presence timer off. The Max Presence function is used to limit presence time, by
automatically resetting the channel. If this function is enabled (ON), the Max Pre sence timer begins counting
down when a call is initiated and t he remaining ti me is continuously displaye d on the LCD. If t he loop becomes
vacant before the Max Presence timer reaches zero, the call is dropped and no automatic reset occurs. If the EndOf-Green (EOG) function is not enabled (OFF) and the call is still present when the Max Presence timer reaches
889-1909-00 Model S-1201 Operations Manual Rev Apr 2020 Page 2 of 29
zero, the cha nnel then is aut omatically reset. If the EOG functi on is e nabled ( ON) and the ca ll is st ill present when
the Max Presence timer reaches zero, the channel enters a Wait state. The Wait state continues until either the loop
becomes vacant or the Phase Green Input signal for a channel (pin J of the MS connector) transitions fro m gree n to
not green with the call still present. If the loop becomes vacant first, the call is dropped and no automatic reset
occurs. If the Phase Green Input transitions from green to not green while a channel is in a Wait state, the channe l
is automatically reset. The signals on pin J of the MS connectors of channels 1 and 2 are also called Call Delay
Overrides. (See Section 3.2, Phase Green Input specification for voltage levels.)
2.7 END-OF-GREEN (EOG)
Each channel’s EOG setting can be toggled ON or OFF by momentarily press ing either t he (UP) or (DOWN)
button. The EOG function is used to synchronize resetting of a detector with the termination of t he associated
phase green. The assumption is that t his is the sa fest point in t ime to reset the c hannel. T his assumption is based
on the premise that at the termination of the associated phase green, traffic should be moving, and therefore, a reset
would not result in t he loss of a call when traffic comes to rest over the loop(s). The E OG funct ion is onl y
available when the Max Presence function is set between 1 and 999 seconds. It is not available when the Max
Presence function is OFF. When the EOG function is enabled (ON), the channel will automatically be reset at the
same time the Phase Green Input signal (pin J of the MS connector) transitions from the ON state to the OFF state,
if the Max Presence Time has c ounted down to zero and is resting in t he wait state. The signals on pin J of the MS
connectors of channels 1 and 2 are also called Call Delay Override. (See Section 3.2, Phase Green Input
specifications for voltage levels.)
2.8 DETECTOR ID
This feature is used to assign a unique identification value to the detector for communication purposes. Detector
ID settings ca n range fro m 000 to 253. NOTE: When first init ialized, t he detector ID s etting is 000.
2.9 OPTION 1: LOOP INDUCTANCE DISPLAY
Each cha n ne l’s Loo p I nd uct a nce Dis p la y se tt in g ca n be t o ggle d O N or O FF b y mo me nta r il y pre ss i ng e it her the
(UP) or (DO W N ) b u t to n. W hen this option is enabled (ON), the LCD displays the total loop inducta nce (actual
loop inductance plus actual lead-in inducta nce) in m icrohe nries for loop inducta nce va lues i n the ran ge of 20 to
2500 microhenries. By recording the inductance of the loop / lead-in circuit when it is first insta lled, the actual
inductance can be compared to the expected ind uctance to help identify defective loop / lead-in circuits. Loop /
lead-in inductance can be easily estimated using the simple formulas included in Section 9.7
NOTE: Enabling this option activates i t for both channe ls. Th is option is automat ica lly disabled 15 m inutes after
activation or on loss of power.
of this manual.
2.10 OPTION 2: LOOP INDUCTANCE -∆L/L DISPLAY
Each cha n ne l’s Loo p Ind uct a nce -∆L/L Display sett ing can be toggled ON or OFF by momentarily press ing either
the (UP) or (DOWN) b utton. When t his option is e nabled (ON), the LCD disp lays the percentage o f
induct ance change (-∆L/L value) during the Call state. To f acilitate t he viewing o f the maximum amo unt of
change in the -∆L/L value while traffic is in motion over the detection zone, the channel holds the peak -∆L/L
value for a period of two seconds. NOTE: Enabling t his option activates it for both channels. This option is
automatically disabled 15 minutes after activation or on loss of power.
2.11 OPTION 3: CA L L EXTENSION CONTROL
Each cha nnel’ s Cal l Exte nsion C ontro l set ting ca n be to ggled O N or OF F by mo mentar ily pre ssin g eithe r the
(UP) or (DOWN) button. Whe n t his op ti o n is ena b led (O N), t he c ha nne l wi ll e xt end ca lls fo r the pro g ra mme d
extens ion t ime only whe n the P has e G ree n Inp ut s i gna l (p in J o f t he M S c on nec to r) is ac ti ve. Whe n t h is op t ion is
OFF, the channel extends ALL calls for the programmed extension time. The signals on pin J of the MS
connectors of channels 1 and 2 are also called Call Delay Overrides. (See Section 3.2, Phase Green Input
specifications for voltage levels.)
2.12 OPTION 4: NOISE FILTER DISABLE
The detector’s Noise Filter Disable setting can be toggled ON or OFF by momentarily pressing either the (UP)
or ( DO WN ) b utt o n. W he n Op t io n 4 is e nab le d ( ON ), inte r na l no is e f ilt er in g is d isa ble d t hus p ro vid in g a fas te r
response time. When t his option is OFF, inter nal noise filtering is utilized. When the detector is used in speed
and/or occupancy applications, the noise filter s hould be disabled (i.e. Option 4 ON) to provide the most accurate
data possible. It is recommended t hat this option not be activated. The factory default setting o f OFF provides
stable operation in high crosstalk e nvironments. NOTE: Enabling this option activates it for both channels.
Changing the setting of this feature will reset both detector channels.
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The Loop Fail Count is not reset when the setting of Option 4 is changed. Also, c hanging t he setting of Optio n 4
will not cause the prior Loop Fail indication to cease (see Section 5.3, Loop Fail Indications).
2.13 OPTION 5: PHASE GREEN LOOP COMPENSATION
Each channel’s Phase Green Loop Compensation setting can be toggled ON or OFF by momentarily pressing
either the (UP) o r (DOWN) button. When Option 5 is enabled (ON), normal loop compensation is used until
the Phase Green Input signal (pin J of the MS connector) becomes active. Once the Phase Green Input signal is
active1, the channel desensitizes the loop. Maximu m desensitization is 0.05% (-∆L/L). This desensitization tunes
out sma ll chan ges, suc h as ad jacent la ne pick up, the refore minimiz ing t he chance of max t iming a n empty lane.
Note: A small motorcycle may also be tuned out in a s hor t pe r iod o f time following the start of Phase Gr ee n. This
option is useful in minimizing false detection resulting from adjacent lane pick up when a channel must be r un with
a high sensitivity setting. When Option 5 is not enabled (OFF), normal loop compensation is used.
2.14 OPTION 6: VEHICLE COUNTING DISPLAY
Option 6 has two parameters, Option 6.0 and Option 6.1.
When Option 6.0 is enabled (ON) for a channel, the normal operating displa y for that c hannel is replaced w ith
the accumulated vehicle count. The unit is capable of accumulating 65,535 vehicle counts before rolling over to
zero. The display will show the hundreds, tens, and o nes digits until the accumulated count e xceeds 999. At
this point the display will alternate be tween the ten thousands and thousands d igits and the remaining three di g its
for hundreds, tens, and ones.
When the detector is first powered up, the detector enters a training mode . Operation in the training mode is
indicated by the accumulated vehicle count flashing on the LCD. Training mode enables the detector to identify
what degree of inductance change a typical vehicle causes as it is detected. When the training period is
complete, the flashing display of the accumulated vehicle count on the LCD will cease and the LCD will show
the actual accumulated vehicle count. The most accurate vehicle counts are obtained once the detector is
operating in this mode, i.e. after the training period is complete.
Option 6.1 is used to reset the accumulated vehicle count for the selected channel. When Option 6.1 is changed
from the OFF state to the ON state, the accumulated vehicle count for the selected channel is reset to zero.
Option 6.1 will always be in the O FF state whe n first vie wed. The acc umulate d ve hicle count is also cleared by
loss of power.
2.15 OPTION 7: VEHICLE COUNTING LOOP CONFIGURATION
Each detector channels’s Vehicle Count ing Loop Configuration setting can be set from 01 to 04. This setting
should indicate the number of loops installed in a single lane. The setting 01 would ind icate a single loop. This
could be a single 6΄ x 6΄ or a long loop such as a 6΄ x 50΄ Quadrupole
number of 6΄ x 6΄ loops installed in a single lane of traffic.
Several factors can influence the count accuracy achieved with this detector:
1. Lanes per Detector - The detector was designed to be used in applications where each channel is used to
count vehicles in a single lane of traffic. It is not intended to be us ed in applications where it is necessary
to count cars across multiple lanes of traffic.
2. Loop Geometry - In the multiple loop settings (02-04), all l oops must be of the same configuration, i.e. the
same number of turns and the same size. Also, all loops must be equally spaced. The ideal spacing for 6 ft.
by 6 ft. loops is 15 ft. center to center or 9 ft. spac ing between loop ed ges. Further, multiple loops should
always be wired in a series network. This is important to ensure that a vehicle passing over the group of
loops c auses the s ame amo u nt o f in d uc t a nce chan ge i n e a c h lo o p . I n the single loop setting (01), square or
rectangular configurations will give slightly better results than Quadr upo le
3. Loop Placement - Loops should a lways be p laced in the center o f the traveled lane. Loops s hould extend
out in front of the stop bar. For turning movements, loops s hould not extend so far out in front of the stop
bar that exiting vehicles would exit more out of the side of the loop than out the fro nt of the loop. If the
detector is operating in the multiple loop mode and other moveme nts of traffi c clippin g the fro nt edge of
the loop are a concern, the detector will only count vehicles that cross more than one loop. It will ignore all
vehicles that clip a single loop.
4. Sensitivity Setting - The se nsiti vity s hould be set so that a single passenger vehicle in the detection zone
creates a seven dot deflection on the bar graph on the LCD.
Whenever the detector is powered up, the sensitivity is cha nged, or the loop configuratio n is changed, the detector
will enter the training mode. W h ile in t h is mo de , t he de t ec t o r is e va l ua ting ind iv i d ual vehic le s pa s sing thr o u gh the
detection zone. This means that no other vehicle can occupy any part of the detectio n zone while a vehicle passes
TM
. The remaining three settings indicate the
TM
configurations.
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Loop B
Loop A
through. The detector w ill accu mulate cou nts during the training period. Opt imal coun t accurac y will occu r after
the training period is complete. Depending on traffic de nsity and the length of detection zone, t his training period
could take many hours. We recommend installing t he detector the day before actual vehicle counts are to be
collected. This will allow sufficie nt time for the dete ctor to train itse lf. The training pe riod is necessar y to ensure
that the detector can adjust itself to the e xa ct pa rticulars of a given loop installation.
The veh icle counting feature cannot be turned off and is active regardless of any other features that have been
enabled. Even if other features (Delay, Third Car Passage, Directional Logic, or Detector Disconnect) would cause
the normal detector output to be in the No Call state, the vehicle counting feature will still operate correct ly.
2.16 OPTION 9: THIRD CAR PASSAGE
Each channel’s Third Car Passage setting can be toggled ON or OFF by momentarily pressing either the (UP) or
(DO WN ) b ut to n. O p tio n 9 is a p a ire d cha nne l opt io n. Th is me a ns t hat it t ake s t w o c ha nne ls to i mplement t he
feature. Therefore, when this option is toggled ON or OFF in one channel, its paired channe l is a lso set to the sa me
state. In the Model S-1201, Channel 1 is paired with Channel 2. NOTE: Option 9 is mutually exclusiv e with
Option 10. Turning ON one option will automatically turn OFF the other option.
When Op t ion 9 is e nab led (ON ) , t he o utp u t o f the tw o pa ir ed c ha n ne ls a re log ic a lly AND ed t o get he r. Th is mea ns
that while the loops for both of the paired channels are occupied, a call will be o utput on both channels. While
only one channel is occupied, or neither channel is occupied, a call will not be output for either cha nnel. The first
channel with detection w ill ente r a pe ndin g state w hile wait ing for detect ion o n the other pa ired c hannel. While in
the pending state, the LCD will show Pnd on the d isplay.
This feature is intended to be used in Pro tected / Permissive left turn situations. The expected ins tallation is a stop
bar loop for the left turn lane connected to one channe l, a q ueue detectio n loop (w ith a s mall amount of de lay ti me
programmed) for the left turn lane connected to the other channel, and the output of eithe r channel conne cted to the
Vehicle Call input for the protected movement of the traffic controller.
Basic Installation - Loop A is the Queue Detec tion lo op and
Loop B is the Stop Bar loop.
Car enters Loop A - No ca ll is o utp ut.
Car proceeds to Loop B - No call is output.
Additional cars enter the left t ur n lane - W hen the ba ck o f t he
queue reaches Loop A while a car is still over Loop B, a call
will be output.
When T hird Car P assage is turned o n, as the fi rst vehi cle enter s the left turn lane it will d rive ove r the queue
detection loop. Since there is no vehicle over the stop bar loop, there is no ca ll output generated. The vehicle
advances to the stop bar loop. Still, no output is generate d because there is no vehicle over the queue detection
loop. If the vehicle traffic in the left turn lane backs up to the queue detection loop, t hen t he stop bar loop a nd t he
queue detection loop will both be occupied at the same time. This will cause the detector to generate a call to the
traffic controller to service the protected movement for the left turn. This sho uld hel p cle ar t he q ueue of ve hi cles
in the left turn lane. The spacing between the stop bar loop and the queue detection loop controls the size of the
queue needed to generate a call to the protected movement of the controller. The delay time on the Q ueue
Detection loop should be sufficiently long that vehic les driving over this loop to enter the queue do not generate a
call.
2.17 OPTION 10: DIRECTIONAL LOGIC
Each channel’s Directional Logic setting can be toggled ON or OFF by momentarily pressing either the (UP) or
(DOWN) button. Option 10 is a paired c hannel option. This means that it takes two channe ls to implement t he
feature. Therefore, when this option is toggled ON or OFF in one channel, its paired channe l is a lso set to the sa me
state. In the M odel S-1201, Channe l 1 is p aired with C hanne l 2. NOT E: Opt ion 10 is mutua lly exc lusi ve wit h
Optio n 9. Turni ng ON one o ption will auto matica lly turn O F F the other option.
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