Intelligent Transportation Systems - City of Oakland

TS-1 and TS-2 Options
In addition to the controller types described above, the National Electrical Manufacturing
Association (NEMA) has new standards for controller and cabinet options. The current
standard is TS1, which is mostly proprietary and provides hardwired connection to the
controller. Two new standards have been adopted by NEMA, TS-2 Type 1, and TS-2
Type 2.
TS1 standard has set minimum requirements for safe and effective controllers, conflict
monitors, loop detectors, load switches, flashers and terminals and facilities for a NEMA
based system. These requirements encompass environmental and AC power
specifications, functions specifications and for the actuated controller option and
connections to the controllers, through A, B, C and D connectors. TS1, however, does
not have auxiliary functional specifications, such as coordination, preemption, time base
control, automatic flash, diagnostics and telemetry. These functions have been
implemented and available in a TS-1 standard in different ways by different
manufacturers using a proprietary D connector and a telemetry connector, resulting in
lack of interchangeability of the equipment between manufacturers. TS1 also does not
specify the user interface, diagnostics or event logging. Currently, most of the City of
Oakland traffic signal controllers and cabinets are NEMA TS1 controllers.
NEMA approved the TS-2 standards in 1992. TS-2 specifies controllers and cabinet by
covering auxiliary functions such as coordination, preemption, time base control, and
automatic flash. The TS-2 advantage is that there is no longer a proprietary item based
on a manufacturer specific D connection. System level communications with devices
outside of the traffic cabinet can be fully specified by the NTCIP protocols.
The higher level of standardization provided by the TS-2 makes it easier for the multiplesource
controllers and cabinets to upgrade from one model to another, and to
interconnect cabinets from different manufacturers on the system via standardized
telemetry.
The TS-2 Type 1 is the pure TS-2 cabinet and controller. The standard A, B, C, D
cables are replaced by a SDLC serial data bus, which provides two-way communication
between all cabinet components. The serial bus interfaces it connector to the detectors
and load switch via Bus Interface Units (BIUs). The TS-2 Type 1 offers standardized
interface. The bus interfaces also allows cabinet level diagnostics.
The TS-2 Type 2 is a hybrid cabinet and controller, which retains some of the TS-1
features. The cabinet provides both the SDLC serial interface of TS2 and the A, B, and
C connectors of TS-1. As a minimum, the serial data bus is used to interconnect the
controller and the conflict monitor (called Malfunction Management Unit – MMU in the
TS-2 standard). The serial bus can be connected to the detector units as well. The A, B
and C connectors are continued to be used to interface the controller to detectors, load
switch and auxiliary equipment.
The disadvantage of a TS-2 cabinet is potential maintenance costs. A typical TS-2
cabinet will require an oscilloscope for diagnostics and maintenance functions. These
features will result in an increase in the initial training requirement by City staff and
familiarity with the TS-2 standard. However, a TS-1 cabinet can still provide similar
functional capabilities as the TS-2 controller/cabinets.
City of Oakland ITS Strategic Plan
31 September, 2003