The Interval program is based on a set of signal group intervals within a fixed cycle length. The cycle length and intervals have a range of 1-255 seconds. The cycle length is entered as the first interval time on the plan. The program cycle counter counts upwards from zero turning on each interval as it progresses. The cycle counter is shown in line 3 of the Base display of the terminal.

As the cycle counter counts up, it reaches an interval time. At that time, the program looks at the new requested signal groups and those that are already green (in service). If the same signal group is called for, it will remain green. If any signal group that is green is not requested again, it will terminate. When all terminating signal groups are out of service, the new signal groups will turn green.

Signal groups maybe semi actuated. Semi actuated signal groups will always turn green at the next interval time but then time by detector extension. If the minimum green time is complete and there is a Goto group assigned and the extension timer times out before the next interval, the Goto group will turn green once the parent group has completely terminated AND there are no other terminating groups currently timing.

Signal groups maybe fully actuated. Fully actuated signal groups will only turn green at their interval time if there is a detector call present or if another group in the interval has a call. Once green, they operate in the same manner as a semi actuated signal group.

An interval can be skipped if there are no calls on any signal group. In this case, the current interval will be skipped and the next interval will time regardless of the call status. The new interval will “Hold” until its normal interval time when the hold will drop. This allows the cycle timer to catch up to the current interval.

An interval will not be skipped if there is a call on any signal group. All groups will turn green even fully actuated groups with no detector calls. Once an actuated signal group has timed its minimum green, it operates as any semi actuated signal group.

The interval times and signal group flags make up a traffic signal plan. The plan can run Free or Coordinated by Time of Day. The program has 8 available plans and a Time of Day scheduler. The program also contains an exception day scheduler for special Holiday operation by Date.

The Interval program provides an easy to use yet powerful tool to help solve the most demanding traffic applications.

Eight programmable detector inputs are available, as is police manual control. A plug-connected 6-channel green conflict monitor (CMU) is an available option.

Because of the small physical size of the complete electronics, the controller CPU and power driver board / load switch assembly can be housed in a small-pole mounted cabinet with enough room to accommodate detectors. The SBC-2400, load switch boards, and recommended conflict monitor unit operate on 12 VDC, which can be supplied by the same off-the-shelf 12 VDC switching power supply or by solar panels.