TecNote 3011 – NTCIP Database Guidelines Part II
This TecNote extends the controller operation described in TecNote 3010 - "Guidelines For NTCIP Databases Part I". These enhancements are recommended for "power users" who want to take advantage of the following Naztec controller features:
Twice Per Cycle Left-Turn (TPCLT) Operation
Enabling Detector Diagnostics and Error Recovery
Defeating Detector Diagnostics During Free
Operation
Enabling Volume and Occupancy Counts
Enabling Detector Switching
If you use STD8Ø (standard 8 phase) operation and do not wish to use these features, just ignore this TecNote and follow the guidelines presented in TecNote 3010. However, if you wish to take advantage of any of these advanced features, you can easily modify the "Data Template" from TecNote 3010 for copy the Screen database changes in StreetWise to any (or all) controllers in your system.
Modifying the NTCIP Database For Twice Per Cycle Left-Turns
TecNote 1102 - "Twice Per Cycle Left-Turns" fully describes this enhanced feature. This section provides step-bay-step instructions to provide TPCLT in your standard Data Template.
Provide a Phase Sequence for TPCLT Operation
To use Twice Per Cycle Left-Turn sequences, you must change the Phase Mode on the unit parameters screen from STD8Ø to USER. Before you can change this setting, you must turn the Run Timer OFF (MM->1->7). You will also need to turn the Run Timer ON after the Phase Mode setting is changed. USER mode is required to use phases 9 through 16 or rings 3 and 4 in the phase sequence definition.
Modify sequence #16 in the sequence table (MM->1->2-4) as shown below. This sequence replaces the lag / lag sequence in your Data Template.
|
16 |
|
| Twice Per Cycle LeftTurns | R1:
1 2 9 3 4 11 R2: 5 6 13 7 8 15 |
Warning!!!: DO NOT use Twice Per Cycle Left-Turn Operation if a left-turn signal display contains protected and permitted indications unless you follow all of the guidelines in TecNote 1103 - The Permitted Lag Left-Turn Display or some other method approved by your Agency. Naztec, Inc. assumes no liability for the "Yellow Trap" safety problem discussed in these TecNotes.
Define the Channel Assignments for Twice Per Cycle Left-Turns
NTCIP and TS-2 refer to a load switches as a "channel". The controller software allows you to drive a load switch with any vehicle, ped or phase output. In the Naztec TS-2 controller, this assignment is made from the Main Menu using the sequence MM->1->3->1.
These channel (Chan) assignments are required to drive the protected left-turn displays using overlaps 9, 11, 13 and 15. The overlaps are defined using the standard left-turn phases 1, 3, 5 and 7 with auxiliary left-turn phases 9, 11, 13 and 15 as discussed in TecNote 1102 - "Twice Per Cycle Left-Turns"
The important thing to note here is that the outputs for the protected left-turn displays are reassigned in software without having to modify the field wiring in the controller cabinets. The same load switches are used to drive the protected left-turn displays, but are now driven by an overlap rather than a single phase.
Note that the Flash settings are all set to RED. This cause the intersection to go to an all-way red flash when the flash switch is activated in the cabinet door (automatic flash).
Enable the Auxiliary Left-Turn Phases for TPCLT
The auxiliary left-turn phases 9, 11, 13 and 15 are enabled from the Main Menu using key sequence MM->1->1->2. Use your right arrow to cursor to the right-hand screen from this menu.
Even though these auxiliary left-turn phases are enabled, they are not serviced unless the controller is running sequence 16 because phases 9 through 16 are not included in sequences 1-15. You do will not service any of these auxiliary left-turn phases unless you specifically call for sequence #16 in a timing pattern.
Define the Concurrent Phases for TPCLT
The concurrent phases for this sequence are defined in the table MM->1->1->4.
Concurrent phases define the "barriers" for multi-ring controllers under NTCIP. Phases 9, 11, 13 and 15 are included as concurrent phases to provide TPCLT operation using sequence #16.
Define the Overlaps for TPCLT
The Data Template defines Overlaps 9, 11, 13 and 15 for TPCLT operation. The user is encouraged to enter any additional standard overlaps in the Data Template.
Overlaps are defined using the controller sequence MM->1->5->2.
Note: NEMA has traditionally labeled overlaps using a character sequence. For example, Overlap 1 is also referred to as overlap A, Overlap 2 is Overlap B. In this example, Overlap 9 is Overlap I:
In this Data Template, overlap 9 is programmed for parent phases 1 and 9 using the keyboard sequence MM->1->5->2->9 ENTER ->1
Ovrlp I Øs..................... Included Øs 5 9 0 0 0 0 0 0 Modifier Øs 0 0 0 0 0 0 0 0 Type:NORMAL Grn: 0 Yel: 3.5 Red: 1.5
Overlaps 9, 11, 13 and 15 are used for TPCLT and are summarized as follows. Note that the overlap numbers and the auxiliary left-turn phases numbers for TPCLT operation are the same and that the auxiliary left-turn is the same as the left-turn phase plus eight. This numbering was chosen to simplify the phase numbers for TPCLT and to keep overlaps 1 through 8 open for the user to define.
| Load
Switch Channel Output |
Overlap
Assigned To Channel |
Phases
Assigned To Overlap |
| 1 | 9 ( I ) | 1, 9 |
| 3 | 11 ( J ) | 3, 11 |
| 5 | 13 ( K ) | 5, 13 |
| 7 | 15 ( L ) | 7, 15 |
Note: The overlaps clearances in this Data Template are timed with the parent phase clearances - set "Parent Ø Clrncs" value ON under the "General Overlap Parameters" screen (MM->1->5->1). When you customize the phase timing for each controller, the clearance times for phases 1 and 9, phases 3 and 11, phases 5 and 13 and phases 7 and 15 should be the same. This insures that the overlaps used for TPCLT operation use the phase clearances times because the "Parent Ø Clrncs" value set ON.
Detector Operation for TPCLT
The controller is initialized with detectors 1 through 8 calling phases 1 through 8. Even though we have set up sequence #16 to service auxiliary left-turn phases 9, 11, 13 and 15, we have no way of calling these phases from detectors 1, 3, 5 and 7. What we need is a way to call phases 1 and 9 from detector 1. The Naztec controller allows you to indirectly source (Src) a detector call from another detector on screen MM->5->3.
If the Src of a detector is zero, then that detector is called directly. For example, detector #52 above is called by detector 52. However, detector #51 is sourced from detector #1.
Detectors 51, 53, 55 and 57 are programmed to call the auxiliary left-turn phases 9, 11, 13 and 15 using the "Detector Parameters" under screen MM->5->1
Using these assignments, detectors 1, 3, 5 and 7 call left-turn phases 1, 3, 5 and 7 and also indirectly call the auxiliary left-turn phases 9, 11, 13 and 15 using the source feature to redirect the vehicle calls. This method allows each left-turn detector to call two separate phases as discussed in the TecNote on TPCLT operation.
Enabling TS-2 Detector Diagnostics and Recovery
Use your left or right arrow keys to scroll to the "right" screen of MM->5->1 and adjust the settings as shown below:
These defaults will enable the controller detector diagnostics for detectors 1 through 8 (these diagnostics are disabled when the controller is initialized with zero values for NoAct, MaxPres and ErrCnt). The values above will generate a detector failure (recorded in the occupancy data) when a detector has no call (No Activity) or a constant call (MaxPres) for a period of 15 minutes. A separate diagnostic will generate an error if there are more than 40 counts per minute (cpm) indicating an "ErrCnt" or chattering detector.
The "FailTime" defaults to zero which disable the ability of the controller to extend an artificial call placed on the phase when one of the detector diagnostics fail. The user should customize the "FailTime" to extend this artificial call longer than the min time of the phase if desired.
The controller also provides a similar set of diagnostics for pedestrian pushbuttons under screen MM->5->4. Ped buttons can be checked for "NoAct" (No Activity), "MaxPres" (max presence or constant call) and "ErrCnt" (chattering pedestrian detector. The system can generate a "Pedestrian Detector Alarm" for these conditions. The controller initializes the "NoAct", "MaxPres" and "ErrCnt" values to zero which disables pedestrian detector diagnostics in the Data Template.
After you have programmed NoAct, MaxPres and ErrCntl times into the controller, take a look at the detector status screen under MM->5->7->1. You will notice that Veh Calls for detectors 1 thorugh 8 are inactive and Veh Alarms are inactive. Now, power down the controller and go back to status screen MM->5->7->1 (this puts a call into each phase on start-up). After 15 minutes of no-activity (NoAct), you will notice Veh Calls and Veh Alarms for phases 1 through 8. The detector diagnostic places a min recall on each phase until a detector call resets the no activity timer. This feature is very useful during "moderate" to "heavy" traffic volume periods; however, late at night, the diagnostic can generate unnecessary alarms. In the next section, you will learn how to defeat this feature by time-of-day using an alternate detector map.
Defeating Detector Diagnostics During Free Operation
In the last section, we learned how to enable detector diagnostics to check for no activity, constant call and chattering detectors. No activity errors can be expected late at night during free operation, so this section shows you how to use alternate detector maps to disable detector diagnostics during free operation.
Take a look at Alternate Detector Map #1 under MM->5->5->1 ENTER. Notice that the alternate map options are the same as the detector options under screen MM->5. The alternate map is used to overlay these normal detector options when associated with a timing pattern.
Go to MM->5->5->1 ENTER 1, to modify the Vehicle Parameters for any detectors that you want to redefine by the alternate map (in this case detectors 1 through 8). Each detector number (Det#) specified in this map is redefined by the alternate detector map. Other detectors defined in the controller are not modified by the alternate map if they are not listed in this table.
This example provides a 8.5" delay for through phases 2, 4, 6, and 8 during free operation to reduce the problem of pre-mature gap-out from right-turns on red during free operation.
Scroll to the right screen from this menu to disable the detector diagnostics for detectors 1 through 8.
Now, modify the Veh Options for detectors 1 - 8 called for in this alternate map - MM->5->5->1 ENTER 2. If you forget this step, detectors 1 through 8 will no longer call and extend. Also, make sure that Add.Init is programmed for each detector or the detector will not be able to added time to the min (initial) green.
You can modify Veh Parms+ for Detector Map #1 on screen MM->5->5->1 ENTER 3 if you want to override any of the Parms+ features with this detector map:
You can also override the pedestrian call detectors under "Ped Parms" for Detector Map #1 - MM->5->5->1 ENTER 4. However, leaving "Ped Parms" blank for the map will not override the standard pedestrian calls in the controller.
To assign Alternate Detector Map #1 to Pattern 48 (Free Operation), go to the Alt Tables+ menu (MM->2->6) and scroll down to Pat# 48.
Whenever Pattern 48 is called, the controller goes to free operation and alternate detector map (DetGrp) #1 overlays the standard detector definitions. This detector map disables detector diagnostics for detectors 1 through 8 during free operation.
Enabling Volume and Occupancy Counts
Occupancy is a measure of the percentage of time that a vehicle is over a detector. The Naztec controller can sample occupancy during the green, yellow and or red interval of the vehicle phase that it calls. The controller is initialized with occupancy turned off, so the Vehicle Parameters+ screen must be modified to sample occupancy during the green and yellow period as follows (MM->5->3).
An "X" in the "G" and "Y" columns of this data template allows occupancy to be sampled during the green and yellow periods for detectors 1 through 8. Occupancy measured during the red interval is meaningless for local intersection detectors because vehicles are stopped on the detectors during the red portion of the phase. System detectors located far enough upstream to avoid queuing during the red interval can be sampled during G + Y + R.
Enable Volume and Occupancy for Vehicle Calls 1 Through 8
Volume and occupancy must be enabled under the "Vehicle Options" screen MM->5->2 (scroll to the right screen).
The occupancy sample rate defaults to 15 minutes when the controller is initialized (see screen MM->5->8->1). A fifteen minute sample is considered adequate for the standard controller Data Template.
The Data Template above assumes that all detectors in adjacent traffic lanes are are wired to separate detector inputs. Just remember, that Volume can only be sampled accurately with one detector per lane per detector channel.
Switch detectors are useful in systems with permitted left-turn signals. Enabling switch detectors allows the left-turn detectors to extend the opposing through phases when the turn phase is red and the adjacent through phase is green.
Detector switching uses the source (Src) feature described under the above section on Twice Per Cycle Left-turns. Switch detectors 52, 54, 56 and 58 are indirectly sourced (Src) from Det # 1, 3, 5 and 7 because each detector can be a call detector or a switch detector (but not both).
Detector switching is provided for detectors 52, 54, 56 and 58 on the Vehicle Parameters+ screen (MM->5->3) as follows.
If you have already modified your Data Template for Twice Per Cycle Left-Turns, screen MM->5->3 should be appear as follows:
Make sure detectors 51 - 58 are programmed for Call and Extend under MM->5-> 2.
Detector switching is programmed for detectors 52, 54, 56 and 58 using the "Detector Parameters" under screen MM->5->1:
If you have already modified your Data Template for Twice Per Cycle Left-Turns, screen MM->5->1 should be appear as follows:
Switch detectors should not be used for protected-only left-turns. Unless the left-turn is permitted on a green ball indication, there is no need to extend the opposing through phase with detector switching. You can defeat detector switching by changing the "Src" of Det# 52, 54, 56 and 58 to zero.