Diablo DSP-22-2 User manual

DSP-22-2_MAN_A 07/20/18 Page 1 of 25 Pros Who Know Trust Diablo
User Manual
DSP-22-2
Low Power, Dual Channel Vehicle
Detector with Support for the Mini-
Loop Probe

DSP-22-2 User Manual Page 2 of 25 DSP-22-2_MAN_A
Contents
Figures ....................................................................................................................................................................3
1. Introduction ...........................................................................................................................................4
Functional Data.......................................................................................................................................................5
Electrical Data.........................................................................................................................................................6
Environmental Data................................................................................................................................................6
Mechanical Data.....................................................................................................................................................7
2. Features and Functions...........................................................................................................................8
Detector Reset........................................................................................................................................................8
Channel 1 – Sensitivity (DIP Switches 1 and 2).......................................................................................................8
Channel 1 – Normal Sensitivity / Sensitivity Boost (DIP Switch 3) .........................................................................8
Channel 1 – Frequency (S3 DIP Switches 1 and 2)..................................................................................................9
Channel 2 – Sensitivity (DIP Switches 4 and 5).......................................................................................................9
Channel 2 – Normal Sensitivity / Sensitivity Boost (DIP Switch 6) .......................................................................10
Channel 2 – Presence / Pulse (DIP Switch 7) ........................................................................................................10
Channel 2 – Loop / Probe (DIP Switch 8)..............................................................................................................11
Channel 2 – Frequency (S3 DIP Switches 3 and 4)................................................................................................11
Indicators..............................................................................................................................................................12
3. Installation ...........................................................................................................................................15
General Rules and Best Practices for Inductive Loops .........................................................................................15
Detector Installation.............................................................................................................................................16
Loop Installation ...................................................................................................................................................17
Mini-Loop Probe Installation ................................................................................................................................20
4. Troubleshooting ...................................................................................................................................22
No Power LED .......................................................................................................................................................22
Detect LED Flashes On Once Every Two Seconds.................................................................................................22
Detect LED Flashes On Twice Every Two Seconds................................................................................................22
Detect LED Flashes at the Same Time as the Power LED every Two Seconds......................................................23
Power LED Intermittently Comes On (Not Once Every 2 Seconds)......................................................................23
Detect LED Intermittently Comes On / Stays On Without a Vehicle Present.......................................................23
Detect LED Will Not Come On With a Vehicle Present.........................................................................................24

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Figures
Figure 1: Product Views..............................................................................................................................................4
Figure 2: Physical Dimensions ....................................................................................................................................7
Figure 3: Loop Installation ....................................................................................................................................... 19
Figure 4: Saw Cut for Home Run Exit and Chiseled Corner for Home Run Exit....................................................... 19
Figure 5 Typical Mini-Loop Probe Installation......................................................................................................... 20

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1. Introduction
The DSP-22-2 detector is intended to be a two-channel detector that can work with both inductive loops as well
as the new Diablo Control Mini-Loop Probe. The detector is powered by a high-performance 8-bit microcontroller
that does not skimp on performance. The DSP-22-2 detector has a small footprint and was designed to directly
plug into many DoorKing operators.
The detector uses a 3-pin Molex connector for its power connections and the Channel 1 solid state output. The
Channel 2 relay outputs have separate screw terminals for wired connections.
Figure 1: Product Views

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Functional Data
Sensitivity: Four sensitivities for each channel are user selectable.
Channel 1:
S
1
DIP Switch
Sensitivity
1
2
OFF
OFF
.
32
% ΔL/L
Low
OFF
ON
.
16
% ΔL/L Medium
Low
ON
OFF
.
08
% ΔL/L Medium
High
ON
ON
.
04
% ΔL/L
High
Channel 2:
S
1
DIP Switch
Sensitivity
4
5
OFF
OFF
.
32
% ΔL/L
Low
OFF
ON
.
16
% ΔL/L Medium
Low
ON
OFF
.
08
% ΔL/L Medium
High
ON
ON
.
04
% ΔL/L
High
Frequency Settings: There are four frequency settings available. The actual loop frequency is
dependent on loop circuit inductance.
Channel 1:
S
3
DIP Switch
Frequency
1
2
OFF
OFF
High
ON
OFF
Medium High
O
FF
O
N
Medium Low
ON
ON
Low
Channel 2:
S
3
DIP Switch
Frequency
3
4
OFF
OFF
High
O
N
O
FF
Medium High
O
FF
O
N
Medium Low
ON
ON
Low
B Pulse Output: 250ms ±15ms.
Response Time: 181 ms typical. 314 ms worst case.
Vehicle Hold Time: Both channels will use an extended presence mode of operation. This mode
allows very weak detections to be held for about 15 minutes. Strong detections
can be held for very long periods of time (days or even weeks) as long as power
is not interrupted.

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Electrical Data
Loop Inductance: 20 microhenries to 1500 microhenries (including lead-in inductance). Not all
frequency settings are available at inductances below 30 microhenries.
Operating Voltage: 14 volts to 27 volts DC
Solid State Output Rating: Maximum Output Current: 250 milliamps
Maximum Pull-Up Voltage: 30 volts
Maximum Voltage Drop Across Active Output: 0.3 volts
Relay Output Rating: 30 VDC, 2 amps (resistive)
110 VDC, 0.3 amps (resistive)
125 VAC, 0.5 amps (resistive)
Current Draw: No Channel in Detect 1.62 milliamps typical @ 20VDC.
Channel 1 in Detect 23.94 milliamps typical @ 20VDC.
Channel 2 in Detect 30.75 milliamps typical @ 20VDC.
Both Channels in Detect 33.60 milliamps typical @ 20VDC.
Environmental Data
Operating Temperature: -35°F to 165°F (-37°C to 74°C)
Storage Temperature: -40°F to 176°F (-40°C to 80°C)
Humidity: Up to 95% relative humidity non-condensing

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Mechanical Data
Mounting Position: Any
Housing Material: Lexan
Detector Size: 4.300 inches (High) x 2.950 inches (Wide) x .820 inches (Deep)
109.22 mm (High) x 74.93 mm (Wide) x 20.83 mm (Deep)
Figure 2: Physical Dimensions

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2. Features and Functions
Detector Reset
When any of the DIP switches are changed, the reset button is pressed, or power is cycled to the detector, the
detector will perform a reset. The reset event will last for two seconds while the detector initiates any changes
and waits for all systems to stabilize.
All three LEDs will turn off for 500 milliseconds at the start of the reset event. After that, the Detect 1 and Detect
2 LEDs will flash according to their fail-safe or fail-secure mode of operation. A flash rate that is the same as the
power LED indicates the output is operating as fail-safe. A much faster flash rate indicates that the output is
operating in the fail-secure mode.
NOTE: If a vehicle is over a loop during the reset period it will not be detected.
Channel 1 – Sensitivity (DIP Switches 1 and 2)
Channel 1 has four possible sensitivity levels. In most situations the sensitivity setting medium high (DIP switch 1
OFF and DIP switch 2 ON) will work effectively. For those situations where this setting is not sensitive enough,
raise the sensitivity. For those situations where the detector is overly sensitive, lower the sensitivity one level at
a time until the desired performance is obtained. Remember that semi-trucks look much smaller than a car. So,
do not set or test the sensitivity using a passenger vehicle if semi-truck traffic will be seen over the loop. The
factory default is low (DIP switch 1 OFF and DIP switch 2 OFF).
Like most inductive loop vehicle detectors, the DSP-22-2 directly measures the change in frequency of the loop
and from there, calculates the change in inductance when a vehicle interacts with it. The change in inductance is
measured as %ΔL/L (reads as “percent delta L over L”).
For the four sensitivities, the detection thresholds are:
DIP Switch
Chan
nel 1
Sensitivity
1
2
OFF
OFF
.
32
% ΔL/L
Low
OFF
ON
.
16
% ΔL/L Medium
Low
ON
OFF
.
08
% ΔL/L Medium
High
ON
ON
.
04
% ΔL/L
High
Channel 1 – Normal Sensitivity / Sensitivity Boost (DIP Switch 3)
Each channel of the detector has a user selectable feature that increases the sensitivity of the detector after initial
detection. This feature is most often used to allow a detector to have a lower starting sensitivity and then increase
it after a vehicle has been detected. This is useful in situations where high-bed tractor-trailer vehicles will be
passing over the loop. With this feature the detector may be able to detect the high-bed portion of the vehicle

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without having to be overly sensitive and susceptible to false detections. NOTE: If detection of high-bed tractor-
trailers is required, correctly sized loops must be used.
DIP
Switch 3
Function
OFF
Channel 1 Normal Sensitivity
O
N
Channel 1 Sensitivity Boost
Channel 1 – Frequency (S3 DIP Switches 1 and 2)
When loops are installed sufficiently far apart, any two loops will not interfere with each other. However, if two
loops are fairly close together, say two to four feet apart, the inductive fields may couple together and may
interact causing intermittent false detections. The main variables for inductive coupling are loop size, distance
between loops, and the loop frequency. Loops that are connected to the same DSP-22-2 detector can not interfere
with each other, as the detector will only turn on one of the loops at any point in time (this is referred to as
scanning). To aid in mitigating inductive coupling, each DSP-22-2 unit comes with two frequency switches for each
channel. They are binary coded allowing up to four different operating frequencies.
If there are suspicions that loops are interacting, change one of the detector’s frequency settings for the suspect
channel so that their inherent frequencies are sufficiently different as to no longer interact. If the loops are the
same size and number of turns, setting one channel to high and the other channel to low will provide the maximum
frequency separation.
DIP Switch
Frequency
1
2
OFF
OFF
Channel 1 High
OFF
ON
Channel 1
Medium
High
ON
OFF
Channel 1
Medium
Low
ON
ON
Channel 1 Low
Channel 2 – Sensitivity (DIP Switches 4 and 5)
Channel 1 has four possible sensitivity levels. In most situations the sensitivity setting medium high (DIP switch 1
OFF and DIP switch 2 ON) will work effectively. For those situations where this setting is not sensitive enough,
raise the sensitivity. For those situations where the detector is overly sensitive, lower the sensitivity one level at
a time until the desired performance is obtained. Remember that semi-trucks look much smaller than a car. So,
do not set or test the sensitivity using a passenger vehicle if semi-truck traffic will be seen over the loop. The
factory default is low (DIP switch 1 OFF and DIP switch 2 OFF).
Like most inductive loop vehicle detectors, the DSP-22-2 directly measures the change in frequency of the loop
and from there, calculates the change in inductance when a vehicle interacts with it. The change in inductance is
measured as %ΔL/L (reads as “percent delta L over L”).

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For the four sensitivities, the detection thresholds are:
DIP Switch
Channel 2
Sensitivity
4
5
OFF
OFF
.32% ΔL/L Low
OFF
ON
.16% ΔL/L Medium Low
ON
OFF
.08% ΔL/L Medium High
ON
ON
.04% ΔL/L High
Channel 2 – Normal Sensitivity / Sensitivity Boost (DIP Switch 6)
Each channel of the detector has a user selectable feature that increases the sensitivity of the detector after initial
detection. This feature is most often used to allow a detector to have a lower starting sensitivity and then increase
it after a vehicle has been detected. This is useful in situations where high-bed tractor-trailer vehicles will be
passing over the loop. With this feature the detector may be able to detect the high-bed portion of the vehicle
without having to be overly sensitive and susceptible to false detections. NOTE: If detection of high-bed tractor-
trailers is required, correctly sized loops must be used.
DIP
Switch 6
Function
OFF
Channel 2 Normal Sensitivity
O
N
Channel 2 Sensitivity Boost
Channel 2 – Presence / Pulse (DIP Switch 7)
The operating mode for channel 2 is selected with DIP switch 7 (Presence or Pulse) and affected by the setting of
DIP switch 8 (Loop or Probe). Presence detection for channel 2 is only available in the inductive loop mode of
operation (DIP switch 8 OFF). If channel 2 is in the probe mode of operation only pulse on entry operation is
available regardless of the setting of DIP switch 7.
In the Presence mode of operation, once activated, the output will remain activated for as long as a vehicle is
detected over the loop. After four minutes of continuous detection, the detector will begin a proprietary
algorithm that is designed to be able to reliably detect the vehicle for long periods of time (days or even weeks)
while still being able to drop the detection once the vehicle exits the loop.
When the probe mode of operation is selected (DIP switch 8 ON), pulse on entry is the only detection mode of
operation for Channel 2. If DIP switch 8 is OFF and DIP switch 7 is ON, Channel 2 is in the pulse mode.
When Channel 2 is in the pulse mode of operation, the pulse generated by the output will be 250 milliseconds
long. There are slight differences between the probe pulse mode (DIP switch 8 ON) and the pulse mode (DIP
switch 7 ON). So, they will be explained individually.
If DIP switch 7 is ON and DIP switch 8 is OFF, the way the pulse mode operates is commonly referred to as Pulse
on Entry. In Pulse on Entry mode, the Channel 2 Output will pulse when a vehicle first enters the loop. The output
will not pulse again until the vehicle has vacated the loop. After the pulse has been output, the Detect 2 LED will