Specifications

7-11
TRANSIT PRIORITY OPERATION
INTRODUCTION
The following descriptions relate to the Transit Priority
feature set in the LMD9200 which provides enhanced
service to transit vehicles. The operation is initiated by a
special call placed into the controller unit such that;
1. If not in the transit priority phase, the LMD9200 will
time intermediate phases a little quicker than normal to
get to the transit priority phase(s) sooner than normal.
2. Once achieved, or if already in the transit prior-
ity phase(s), the LMD9200 may extend the transit
priority phase(s) a little bit longer than the normal phase
max or split time if needed. Note that normal max timing
includes normal max 1 or 2, max plans, or fail max
timing—whichever is in effect.
3. Inputs may operate in a single detection pres-
ence mode (constant call) or a two detector “check in,
check out” mode. In this mode, an upstream detector
places a call in memory which is then cleared by a far
side detector once the vehicle has cleared the
intersection.
Other than its priority service, the transit priority phase is
just a normal phase used for general vehicles. Each
transit priority service is in response to a special input
designated for that purpose. Transit priority is not pre-
emption, and is not intended to be as aggressive in
nature. It does not skip phases nor disrupt coordination
as severely as pre-emption typically does.
TRANSIT PRIORITY INPUT MAPPING
-Transit priority service is called for by mappable
inputs designated TP1-6 for priority transit priority 1-6.
To use the transit priority feature, these must be
assigned (mapped) to actual pins as needed.
-To do so, choose available pins that are not needed for
another function and map them accordingly. Be sure to
zero out the pin assignment to the unneeded function so
it will not be falsely activated. See I/O mapping, page
11-3.
Note that:
1. CUSTOM MAPPING must be toggled enabled, and
2. LOAD I/O CONFIG CHANGES must be executed
after assigning transit priority pins.
TRANSIT PRIORITY INPUT SCREENS
I/O configure area, custom I/O mapping, input mapping.
Main Menu-4-2-3-page down 23 times.....
Note: Pins shown are normally ph 1 & 3 ped omits
TPr1-TPr6 = Transit priority request inputs 1-6
TPrI = Transit priority Inhibit (all request inputs)
Pg dwn.....
TPC1-TPC6 = Transit priority clear call from memory
inputs 1-6
Pg dwn....
TIP1-TIP8 = Phase 1-8 conditional transit priority
shorten INHIBIT inputs
INPUT DEFINITIONS
TPr1-TPr6. These call the TP process for the assigned
phases (phase assignment and timing in transit priority
set-up programming). Once the transit priority phase
has been achieved, it will hold until the input goes away
or the transit priority maximum extend period times out.
TPrI. This is an unconditional transit priority inhibit
input, When activated, all transit priority inputs are
inhibited (no transit priority allowed).
TPC1-TPC6. Transit priority memory clear inputs. Each
clears its corresponding call from memory (it also dis-
ables the request input when active). Typically used with
two detector systems where the first is placed on the
near side of the intersection using a TPr (request) input
with memory set to on. The second is on the far side of
the intersection and uses a TPC (clear call) input to
clear the call once the vehicle is through the inter-
section.
TPr1 TPr2 TPr3 TPr4 TPr5 TPr6 TPrI
152 233 0 0 0 0 0
OR OR OR OR OR OR OR
0 0 0 0 0 0 0
TPC1 TPC2 TPC3 TPC4 TPC5 TPC6
0 0 0 0 0 0
OR OR OR OR OR OR
0 0 0 0 0 0
TIP1 TIP2 TIP3 TIP4 TIP5 TIP6
0 0 0 0 0 0
OR OR OR OR OR OR
0 0 0 0 0 0