DSP-100 User Manual
Page 9 of 25
DSP100_MAN_A
Fail Memory Operation
Normal operation during a loop failure is the green Power LED indicating what type of loop failure (open, short,
or large
ΔL/L
). During the loop failure, the red Detect LED and the output will be active for fail-safe operation or
inactive for fail-secure operation. If the loop recovers from its failure, the red LED along with the output will
operate normally again. However, the green LED will display Fail Memory by blinking 1850 milliseconds on, 50
milliseconds off, 50 milliseconds on again, and then 50 milliseconds off. This blinking sequence will repeat until a
reset or power cycle occurs. This blinking sequence will inform the user that sometime in the past this particular
detector detected a loop failure.
Delay (Timing versions only)
Delay is the time added after a vehicle arrives in the detection area but before the output is activated. During the
delay interval the output relay will remain de-activated, requiring that the vehicle stay in the detection area for
the full delay time before activating the output. This is useful at sites where right turns on red are allowed. This
allows a vehicle to arrive at a red signal, come to a full stop, and proceed to make a right turn without the detector
ever activating and placing a call into a phase. This interval is indicated by the red Detect LED blinking slowly at
200 milliseconds on followed by 200 milliseconds off repeatedly until the interval is complete. Delay time can be
set from 1 second to 63 seconds in 1 second increments.
Figure 4: Output with Delay
Delay Inhibit (Timing versions only)
Normal operation always honors any programmed delay time. However, by connecting the AC green input for
that phase to connector pin J (Delay Inhibit), the DSP-100 will delay only when the green is not active. During the
green interval, any programmed delay time will be ignored.
Extension (Timing versions only)
Extension is the time added after a vehicle leaves the detection area. During this interval, the output will remain
activated. If another vehicle arrives during this extension interval, the remainder of the extension time is canceled
and the detector returns to the normal presence state. This interval is indicated by the red Detect LED blinking
fast at 50 milliseconds on followed by 50 milliseconds off repeatedly until the interval is complete. Extension time
can be set from 0.25 seconds to 15.75 seconds in 0.25 second increments.