Step 4 - Check Patterns Using Controller Diagnostics
Get in a habit of running diagnostics on every new timing plan you run in the controller! This will help you isolate and correct errors before they are run in the field. The controller is capable of finding many faults in the coordination plan that are difficult to find because the data is spread out over several screens. It is therefore good practice to systematically step through each plan and check the diagnostic status to see if min times are violated, cycle length is properly specified, etc.
This example isolates several errors generated when the coordination patterns were entered in Step 3. Therefore, to complete the exercise, you must make the corrections noted. When you have completed this section, please return to the TecNote on NTCIP coordination.
Check Pattern 1
Force the controller to run Pattern 1 from the Main Menu using the key sequence MM->2->1->1 ENTER
Diagnose pattern 1 from the using the key sequence MM->2->8->5 which calls up the following Coordination Diagnostic Screen.
This pattern has an error PlanERR and the controller is running free. Confirm this with the key sequence ALT->9 and observe that the Controller is TIMING FREE.
The Fault:SUM NE CYC quickly tells you that Cycle 59 does not equal the sum of the phases in each ring ( SUM=60 ). Go back to Step 3 and note that the 59 in the Pattern Table is highlighted in red.
NTCIP requires that you specify the cycle length in the Pattern Table. Cycle length is not calculated from the split and sequence information. The Naztec diagnostic always checks to make sure that the Cycle length programmed in the Pattern Table equals the sum of the phase splits in each ring.
Correct this error by changing the cycle from 59 to 60 in the Pattern Table (MM->2->4) for Pat #1.
Go back to the Coordination Diagnostic Screen (MM->2->8->5) and note the change in this screen:
Now the coordinator is running ( CoorActv ) with no faults. You can also confirm this with the key sequence ALT->9 and observe that the Controller is TIMING COORD.
The text OK was added after version 50.29, to help clarify the interpretation of this screen. If you have an earlier version of the software, you will see the text Fault with a blank field after the label fault to indicate that the plan is OK.
Check Pattern 2
Force the controller to run Pattern 1 from the Main Menu using the key sequence MM->2->1->2 ENTER
Diagnose pattern 2 from the using the key sequence MM->2->8->5 which calls up the following Coordination Diagnostic Screen.
Again, this pattern has an error ( PlanERR ) and the controller is running free. Confirm this with the key sequence ALT->9 and observe that the Controller is TIMING FREE.
The Fault:SUM NE CYC quickly tells you that Cycle 60 does not equal the sum of the phases in each ring ( SUM=61). Go back to Step 3 and note that the 11 in the Split Table #2 is highlighted in red.
Correct this error by changing the split for phase 1 from 11 to 10 in the Split Table #2 (MM->2->7->2 ENTER 1).
Now, go back to the Coordination Diagnostic Screen (MM->2->8->5) and note pattern #2 is OK.
Diagnostic Checks on Split Times
Before we leave phase 2, lets look at the Stop-in-Walk value you programmed in Step 1. Go to the coordination modes screen (MM->2->1) and scroll first to the right screen, then down one screen using the arrow keys. Notice that the Stop-in-Walk is programmed ON. Go ahead and toggle this value to OFF and go back to the diagnostic screen (MM->2->8->5 ) and observe the plan which was running OK is now failed:
You will get a SPLIT TIM fault whenever the minimums of a phase are not satisfied and one of the following conditions occurs:
1) The sum of the Min + Yellow + All-Red Clearance greater than the split time of a phase
2) The sum of the WALK + Ped Clearance + Yellow + All-Red is greater than the split time
Note: this check is only performed when Stop-in-Walk is OFF and since we just turned off this value, the min time for pedestrian clearance has obviously been violated for phase 2. If you go back to the phase times (MM->1->1->1) you will see that for phase 2, the WALK (5") + Ped Clearance (10") + Yellow (2.5") + All-Red (0.5") totals to 18". The split programmed for phase 2 in Split Table #2 is 20" which is greater than the 18" min time, so why did this plan fail ??.
The coordination diagnostic always checks to make sure that the split time is satisfied if the controller is allowed to go through a short-way offset correction. The controller is currently programmed to reduce the split by 12% using short-way transition. Reducing the split (20") by 12% to 17.6" violates the diagnostic because the split is less than the 18" minimum when Stop-in-Walk is OFF.
Short-way will be discussed fully in the examples, so for right now, prove that short-way is causing the problem by going to screen MM->2->5 and change the value in the "Short" column for Pat #2 from 12 to 0. This disables short-way for pattern 2.
Now go back and check you coordination diagnostic ((MM->2->8->5 ) - the plan is now OK!
This exercise has attempted to illustrate the SPLIT TIME diagnostic checks performed by the controller. Once you understand the relationship between the phase minimums, the Stop-in-Walk setting and the effect of short-way transition, you will be on your way to troubleshoot your own timing patterns before you put them in service on the street.
Please return the Stop-in-Walk setting to ON by going to (MM->2->1). Scroll first to the right screen, then down one screen using the arrow keys to change this value.
Also change short-way transition back to 12 on screen MM->2->5 .
When you have completed this section, please return to the TecNote on coordination.