907 All controllers shall be equippe d so that they may be coordinated with other controllers or supervised by a master system. This shall be possible by the simple addition of accessory equipment external to the controller.
715.42.2 2.1-Phase Sequence Unit: The phase sequence unit must b e an integral part
of the controller main frame and shall establish the order and operation of the Phase Timing in accordance with vehicle and pedestrian detector calls. In the absence of recall or detector actuation, the right -of-way shall remain on the traffic phase upon which the last actuation occurred. The actuation of any detector during the extendible portion of a traffic phase having the right -of-way shall cause the retention of right -of-way by that traffic phase for one unit extension from the ti me of actuation. One unit extension interval of time shall be guaranteed for each vehicle actuation registered during the extendible period. Each actuation shall cancel the remainder of the previous unit extension interval in effect and initiate a comple te new unit extension interval, timed from the instant of actuation. The actuation of a detector on another phase shall cause the right -of-way to transfer to that phase if during the extendible portion of the timing phase there have been no actuations for more than one full unit extension interval of time. An actuation during the clearance period for a traffic phase shall cause the right -of-way to return to that phase in the same manner. Also, when the right -of-way is transferred by operation of the exte nsion limit, the terminated phase shall again receive the right -of-way in the above manner without further detector actuations. The controller shall be equipped with provision for skipping any phase when there is no call for that particular phase. Exact phase sequence when there are calls on three or more traffic phases shall be as specified for each controller chassis type. The term "Phase A" as used shall in all cases refer to the artery or mainline phase. It shall be the first phase in the sequence of phases. Other phases such as B, C etc. shall follow Phase A in alphabetical sequence with right -of-way assigned in accordance with the above, or specified sequence logic.
715.42.2 2.2-Interval Sequence Unit: The interval sequence unit must be an int egral
part of the main frame and shall determine the order and control of the various intervals of each phase. The rotation shall be Green, Yellow, All Red and Red for vehicle movements and Steady Walk, Flashing Don't Walk and Steady Don't Walk for pedest rian movements. The transfer of the right -of-way from any traffic movement shall take place only after a proper clearance period. The clearance period for each vehicular phase shall consist of a vehicle change (Yellow) and an All Red Clearance interval. Each shall be timed separately and the second clearance interval of any phase may be omitted by a simple timing adjustment. The clearance period for a pedestrian movement shall be a Flashing Don't Walk.
715.42.2 2.3-Interval Settings and Adjustments: The controller shall provide a
positive means of setting signal timing intervals. The settings for each interval shall be in seconds or divisions of a second and the controller shall provide a clear visual display of the length of each interval or period. The interval settings shall be color coded, easily identifiable and shall be made by means of dials or thumbwheels. Settings shall be provided for each phase interval and shall be mounted on the front of the associated main frame phase module. It shall not be necessary to use punched data cards, remove or change 908 wires, pins or contacts, or to use tools of any kind in making interval adjustments. All dials shall be on the front of the controller and easily accessible. The minimum green interval shall be equal to either initial and one unit extension, walk plus pedestrian clearance, or walk plus pedestrian clearance plus one extension. The timing of the extension limit shall commence with the first actuation or other registration of traffic deman d for the right -of-way on any traffic phase not having the right - of-way, and should begin after the initial period has expired. In the event the controller reverts to the start -up sequence, the signal operation shall be initiated in the Phase A green inte rval and at least one initial and one unit extension (or vehicle interval) period shall be timed while in that sequence. As part of the initialization routine, vehicle calls shall be placed on all phases. All phases shall be provided with at least the fo llowing intervals and minimum range of interval settings:
i.Initial Interval 0 to 99 Seconds ii. Vehicle Interval (Extension) 0 to 9 Seconds iii. Yellow Interval 0 to 9 Seconds iv. Maximum Extension 10 to 99 Seconds
v.All Red Clearance 0 to 9 Seconds Time spans and actuation limits specified are minimum and may be expanded. Each phase shall be provided with recall and memory control. Capability to initiate the maximum or single unit extension recall shall be provided for each phase. In ad dition, phase memory of vehicle actuations during any interval shall be provided. There shall also be a "Memory Off" control for each phase to delete the memory feature when it is not required. The controller shall be provided with a vehicle call indicat or light for each phase. The indicator light shall respond to each vehicle call on its phase. The indicator light shall go off at the end of the initial portion of the green interval and indicate each actuation momentarily during the extendible portion o f the green interval. Sufficient monitoring lights must be provided on the controller to visually indicate what part of the controller is timing and what function will follow. The monitoring lights shall be an integral part of the controller and must be a standard rather than an optional feature. The front panel of the modules shall be engraved, silk screened or otherwise permanently marked to indicate module type and identify indicator lamps, switches, controls, etc. so that the functions of the module are readily apparent.
715.42.2 2.4-Flashing Operation: For use during periods of low traffic volume or
emergency conditions, a flasher unit shall be provided to flash all signal indications displayed during any specified yellow -red or all -red seq uence. Upon resumption of controller operation of the signal indications, Flashing Red indications must be followed by the Steady Red or Steady Green interval of that sequence and Flashing Yellow must be followed by the Steady Green interval. This logic must be built into each controller main frame chassis. The controller shall be designed such that a fuse failure (open) on the controller side of the power supply will automatically switch the signal to flashing operation.
715.42.2 2.5-Manual Control Fe ature: The controller shall be so designed that by
wiring external to the controller, manual control of signal sequence timing may be 909 assumed. The manual control function may be assumed with the application of the Stop Timing command. The operator may s equence the controller by applying input signals with a Manual Advance Switch.
715.42.2 2.6-Uninterrupted Timing: Normal traffic -actuated operation shall be
resumed automatically after Manual, Flashing Pre -emption or any other special operation has been utilized.
715.42.2 2.7-Stop Timing: Means shall be provided so that on call, timing may be
stopped on any one of all interval timers in the control system. This is provided for the purpose of adding extra intervals or auxiliary equipment, or both. Up on resumption of timing, the interrupted interval shall be timed in its entirety.
715.42.2 2.8-Auxiliary Equipment: The controller shall be so designed that all
standard auxiliary equipment may be added without internal controller modifications. Railro ad or fire station pre -emption equipment shall be constructed and wired so as to transfer control of the signals from either the controller or the flasher unit to the preemption timing unit. Installation of the pre -emption equipment shall not alter the in ternal wiring of the controller chassis normally furnished by the manufacturer. In addition, the controller shall be furnished capable, by the addition of standard accessories external to the controller, of the following functions:
i.Actuated pedestrian tim ing associated with each phase. ii. Minor movements associated with each phase. iii. Overlaps as required.
715.42.2 2.9-Check Circuit: All controllers must be provided with a check circuit to
indicate the presence or absence of an actuation on any of the phases which do not have the right -of-way so that a pedestrian interval timer may be added to any phase without additional equipment, other than the pedestrian timer.
715.42.2 2.10 -Connectors and Wiring Harness: All electrical connections to and
from the controller shall be made through MIL -C-26482 series pin connectors and wiring harness. Each wiring harness shall be at least 4 feet long or of the standard length specified by the manufacturer for that controll er chassis type. The harness end opposite the connector shall have color -coded leads or labeled sleeves. The harness connections shall be mounted on the front of the controller unit in accordance with the following: Connector A shall intermate with an M S3116( ) -22-55S. Connector B shall intermate with an MS3116( ) -22-55P. Connector C shall intermate with an MS3116( ) -24-61P. The wiring harness, harness terminal functions and the MS connectors shall be identical for each connector type. Terminals sha ll be provided for the signal light cable. One terminal for each signal circuit and one or more terminals for the common conductors are required. All field wiring shall be color coded and the terminals labeled. The outgoing signal circuits shall be of t he same polarity as the line side of the power supply and the common return shall be of the same polarity as the ground side of the power supply. 910 A double pole, low -voltage lighting arrestor with mounting bracket shall be mounted on the back panel and wir ing between the power supply and the fuse. All terminals except the interconnect system shall be mounted on the controller panel. The interconnect terminals shall be mounted on the side of the controller cabinet unless otherwise specified.
715.42.2 2.11-Controller Terminal Functions Required: All controller functions
shall be available at the MS connector terminals on the controller chassis. These functions shall be as specified in the latest NEMA standard -identification of input/output pin connector termination. In addition, the controller shall be provided with all terminal functions necessary for plan phasing and to meet the specification requirements. All functions shall be standard controller features and shall be available at the external contr oller terminal points.
715.42.2 2.12 -Per Phase Load Switching Devices: Solid -state, heavy -duty, jack
mounted, per phase load switching units shall be used for opening and closing the signal light circuits. Each switching circuit shall have a minimum ra ting of 10 amperes for a tungsten -lamp or gas -tubing transformer load over a voltage range of 95 to 135 volts at 60 Hz. No more than one circuit shall be energized at any one time unless the combined load on the energized circuits does not exceed a 10 amp ere load. This, power handling capability shall not be derated for operation over the operating ambient temperature range described in the NEMA standards. Covers or cover plates on all switching devices shall be so designed as to be easily removed and re placed by means of set screws or similar replaceable securing devices. All load switches shall intermate with a Cinch -Jones socket S -2412 -SB, or the equivalent. Physical and electrical characteristics of the switches and load racks must conform to the latest NEMA standards. Signal load switches for use with the controller, but for mounting external to the controller units specified, shall be used for switching signal light circuits.
715.42.2 2.13 -Fail Safe: Insofar as possible, all phase and interval sequence logic
internal to the controller shall be such that conflicting signal indications are not possible even during power failures or equipment malfunction. If "failsafe" signal monitoring devices are req uired external to the controller, it must be clearly stated in the manufacturer's instructions. In the same manner, combinations of signal indications expressly prohibited in the Manual on Uniform Traffic Control Devices shall not be possible.
715.42.2 2.14-Warranties and Guarantees: The Contractor or supplier is required to
turn over to the Division any guarantee or warranties which are given by the manufacturer as a normal policy. The Contractor or supplier shall furnish the Division with two copies of complete drawings, diagrams and manufacturer's instructions for installing and maintaining the equipment and any assistance as required for timing and operation of the equipment. Any component called for by the circuit design which has special or uniqu e characteristics which would limit that component to certain manufacturers or suppliers shall be so indicated in the manufacturer's instructions. 911 The Contractor or supplier shall make available to the Division at no cost, engineering data, diagrams, etc. on any later changes or improvements which would increase the performance of the equipment purchased. The Division reserves the right to withhold any payments which may be due, should it be discovered that the equipment does not meet the Specifications. All components specified shall be amply derated with regard to heat dissipating capacity and rated voltage so that, with maximum ambient temperature and maximum applied voltage, material shortening of life or shift in values shall not occur.
715.42.2 3-Solid State Traffic -Actuated Signal Controller (Type C) (Two through
Eight -Phase NEMA -Microprocessor Based -Keyboard Entry): The purpose of this section is to set forth functional specifications for a microprocessor based, fully traffic - actuated dual -ring, functional modular controller unit capable of providing up to eight phase signal operation. Timing and per phase functions shall be programmable by main frame single keyboard entry; per -phase modular entry is not acceptable. Single entry timing mode sha ll be provided. In addition to the above named, the Controller must provide a true MENU format for data entry. As a minimum, a forty (40) character by four (4) line, alpha -numeric liquid crystal data display screen must be provided on the front of the co ntroller. The display must be easily visible in both full daylight and at night. Back lighting the display is required. The general design requirement of 715.42.2.2, as well as the NEMA standards, shall apply except when the specific requirements exceed those in that section of the standards. Phase designation and sequencing shall be as outlined in 715.42.2 of these Specifications. The Controller must be capable of storing timings and other control parameters in an internal data memory. This data mus t then be accessible for display and/or alteration by means of front panel keyboard control and display. Coded memory access or other approved entry control must be provided. Power requirements and recovery from power interruption shall be as specified i n current NEMA standards for solid -state signal controllers. Internal backup battery power to maintain the controller memory for up to one year in the absence of A/C power input must be provided in the controller. Full volume density operation per phase with walk must be an integral part of the controller logic, including variable initial and gap reduction. MUTCD flash operation, overlap programming, multiple phase configurations, partial or full entry capability, last car passage per phase and extended dual ring status display must also be provided in the controller. All inputs, outputs, interface voltage and interface common returns shall be through front panel pin connectors. These connectors shall be as specified in 715.42.2.2.10. I/O pin functions shall be in accordance with current NEMA standards.
715.42.3 : Blank
715.42.4 Local Coordinating Units:
715.42.4 1-General Design Requirements: The following are minimum design and
operating requirements for all types of local coordinating units. The general design requirements apply to master coordinating units and secondary coordinating units; both 912 dial, electromechanical (LCU -EM) and digital , full solid state (LCU -DS). Local coordinating units provided for an interconnected signal system shall be completely compatible with the master controller and all local controllers in that system. The coordinating units described shall be used in conjun ction with solid state traffic actuated signal controllers and traffic adjusted master controllers. The coordinators shall inhibit the internal extension limit in the local controllers and provide external maximum control. Background cycle lengths, split s, system offsets and other coordination functions as required shall be called in by a master controller or coordinator. These functions may also be called in by local or master override or time switches. For definition purposes, traffic phases shall be considered as running in sequence, such as A -B-C-D, etc. Also, any of these phases may consist of two separate auxiliary movements which must begin simultaneously but may end at different times, as long as the following phase is the auxiliary's associated thru-phase. All coordinating units shall be furnished capable of at least the following:
i.Three background time cycles. ii. A separate split associated with each time cycle. iii. Three offsets associated with each time cycle. iv. A variable permissive period for yield ing to minor phases (B,C, etc.).
v.External maximum limits (force offs) as required for all associated phases. vi. System offset interruption, unless provided for in the system master controller. vii. Capability of generating cycle lengths of at least 60 , 70, 80, 90, 100 and 120 in association with each split and each offset. viii. Master -intersection control and supervision of other coordinating units as required. ix. Free operation when called for by the system master, time switch or manual override.
x.A minimum of eleven indep endent in and out functions shall be provided per dial with associated circuitry to provide yield, force off, free operation, system sync, dial transfer, etc. It shall be possible to set offset, splits and all synchronization functions from the front of the coordinating unit. It shall be possible to make these settings in at least one percent (1%) steps to any percentage of the associated cycle length and all such settings shall be clearly indicated. Each coordinating unit shall be plug-connected, and it shall be possible to remove a unit and replace it with a similar unit without shutting off the power to the controller or signals. Removal of the coordinating unit and insertion of the coordinating unit harness receptacle into a sho rting plug, which shall be mounted on the cabinet wall, shall cause the local controller to go to free operation. In addition, each coordinating unit shall be provided with a switch on the front panel for selection of free or coordinated operation and at least the selection of one of three cycle lengths. Synchronization shall only be in effect in the coordinated position. Switch indicator lights shall be provided at the local coordinating units to indicate the synchronization period in e ffect. Absence or conflict of offset or cycle information on the interconnect shall place the coordinating unit in cycle number one, offset number one (average offset) or a pre -set standby cycle. 913 When the controller is working in coordinated operation, t he internal maximum of the controller for Phase A shall be disabled. At all other times, the internal maximum of the controller shall remain operable. Cycle change and transfer from free to coordinated operation shall take place at the first yield point (end of Phase A), unless otherwise specified. When required in the coordinating unit, system offset interruption shall be adjustable in the range of at least 0 to 40 seconds. When the local coordinating unit, for any reason, gets out of synchronization w ith the master system, the length of the dwell in any one cycle shall be limited to the time allowed by the offset interrupter. Timing shall start at the beginning of the dwell. A switch shall be provided to eliminate the offset interrupter from the inter connected system. Any changes in the operation of traffic control signal lights caused by turning the signal lights off, or transfer to flashing or preempt operation shall not interfere with the continued in-time operation of the coordination timer. A tr ansfer from such special operation back to normal automatic operation shall immediately establish the normal time cycle and subsequently the in -time relation. Each coordinating unit shall be furnished with two service manuals complete with all necessary i nstructions and diagrams for the installation and maintenance of the equipment supplied and two complete wiring diagrams. These wiring diagrams shall identify the color code or wire tagging used in all connections.
715.42.4 2: Blank
715.42.4 3-Time B ase Coordinating Units ( Type TBC): The purpose of this section
is to set forth functional specifications and design requirements for signal coordinating units that do not require communications interconnect or synchronous motors to maintain a signal syste m time base. These units will be designated as Time Base Coordinating Units or TBC. The general functional requirements in 715.42.4.1 for "hardwire" coordinating units shall apply to the TBC except where otherwise noted. All units shall be capable of th e coordination of two (2) through eight (8) signal phases per controller. TBC units are to be used in conjunction with solid state traffic actuated signal controllers. The coordinating unit circuitry shall be of the latest solid state digital design. Th e units shall be completely self -contained and designed to be shelf mounted as auxiliary equipment in standard traffic signal controller cabinets. The units shall operate normally on 115 VAC, 60 Hz line power and shall provide immediate standby battery po wer for the clock and programmable memory upon interruption of on -line power. Time base timing accuracy for normal (non -battery) operation shall be 1 second/month of continuous operation. Line voltage tolerance for specified operation shall be up to 13 5 VAC and down to 95 VAC. NEMA specified transient protection shall also be provided with each unit. Operating temperature, humidity and all other environmental tolerances specified in current NEMA standards shall be met. Battery power for standby operat ion shall be of the rechargeable type and provide at least 100 consecutive hours of standby operation after 48 hours of normal operation with a minimum 3 -year life. Standby clock accuracy shall be at least 0.005% in 48 hours. 914 The following programmable f unctions shall be available to the user via front of unit keyboard entry. Minimum 100 time of day (TOD) program events per day of week Four (4) cycle lengths Three (3) offsets per cycle Two (2) daylight savings time changes Free operation selection Four (4) synchronization reference times (1 per cycle) At least eight (8) outputs associated with the above functions shall be provided. Outputs must be provided for synchronization, yield, force -off, phase omit (etc.); in addition, a minimum of three (3) auxiliary outputs shall be available to operate controller functions such as flash, MAX II, change of phase sequence, switching of detectors (etc.). The outputs shall be of the voltage required by the system configuration. All program entrie s shall be available upon demand on a front panel display that is easily readable when shaded from direct sunlight. Output status shall also be available on the unit front panel display. In addition, the unit shall give positive feedback to the programme r that a keyboard entry was made and recognized. This also must be displayed on the front panel by readily discernible means. Program transfer capability via data transfer port and cable must be provided on each unit. Standard interconnecting cable for this function must be provided with each unit.
715.42.5 Traffic Detectors:
715.42.5 1-General Design Requirements: The following are minimum design and
operating requirements for all types of traffic detector units. The general design requirements apply to both the loop detectors and the magnetic probe detectors. Detector units within a traffic -actuated system shal l be completely compatible with the control units in that system. The detector units described shall be used in conjunction with pre -timed fixed cycle traffic signal controllers, solid -state traffic actuated signal controllers and traffic adjusted master system signal controllers. The detector circuitry shall be solid state and all component parts shall be of high quality meeting the maximum acceptable standards of good engineering practices. All components shall be amply derated with regard to heat diss ipating capacity and rated voltage so that, with maximum ambient temperature and maximum applied voltage, material shortening of life or shift in values shall not occur. Any component called for by the circuit design which has special or unique characteri stics which would limit that component to certain manufacturers or suppliers shall be so indicated in the manufacturer's installation, operation and service instructions. The detectors shall be capable of sensing both passage and presence of vehicles and shall not be affected by rain or other weather conditions. It shall be possible to change from passage to presence detection by a selector switch mounted on the outside of the detector unit case. The passage or presence of a vehicle over a road sensor sh all activate an output relay. The pulse detection mode shall provide a short output signal for each vehicle entering the roadway sensor zone of detection.
Source: West Virginia Standard Specifications for Road and Bridge Construction, 2023 Edition. Pages 929–936 of 1,006.