Diablo Controls DSP-20LV Dual Channel Vehicle Detector Directional Logic Control
The Diablo Controls DSP-20LV is a dual-channel vehicle detector for access-control and parking installations that use two loops. It can operate as two separate channels or use directional logic to determine vehicle travel direction from the order in which the two loops are triggered.
This detector is useful on gate and barrier lanes where direction matters, such as entry/exit control, lane sequencing, anti-tailgate support, and systems that need to avoid triggering from vehicles moving the wrong way. The DSP-20 uses advanced channel-scanning technology to improve noise tolerance and to allow tighter loop placement than older single-channel setups in some applications.
The loop layout is just as important as the detector. Directional logic requires the loops to be installed in the correct order, spacing, and travel path. If the loops are damaged, too close to metal, wired incorrectly, or placed poorly, the detector may not behave as expected even if the electronics are working.
Compatible With
Compatibility depends on the detector model, supply voltage, loop or probe type, wiring base, relay output needs, and how the gate, door, barrier, parking, or access-control panel is designed to receive a vehicle-detect signal.
- Two-loop parking and access-control lanes
- Gate operator and barrier gate systems requiring directional logic
- Applications needing two independent detector channels from one detector
- Entry/exit control lanes, anti-tailgate support layouts, and vehicle sequencing applications
- Low-voltage control cabinets that match DSP-20-LV power requirements
- DSP-20LV / DSP-20-LV replacements where connector, voltage, and loop layout match
- Not a replacement for single-channel DSP-10, DSP-11, DSP-15, or probe-only detectors
Features and Specifications
| Manufacturer | Diablo Controls |
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| Product Type | Dual-channel vehicle loop detector |
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| Part Number | DSP-20LV |
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| Application | Directional logic or two-channel loop detection |
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| Supply Voltage | Low-voltage DSP-20-LV application; commonly listed as 10 to 30 VDC / low-voltage range depending on source |
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| Loop Inputs | Two inductive loop channels |
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| Operating Modes | Two independent channels or directional logic mode |
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| Output Options | Selectable presence or pulse operation |
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| Fault Features | Loop monitoring and fault memory |
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| Notes | Loop spacing and travel direction must match the directional logic setup |
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Also Known As / Related Part Numbers
- DSP-20LV
- DSP-20-LV
- DSP-20
- DSP20LV
- DSP20
- Diablo DSP-20 dual channel detector
- Diablo directional logic detector
- DSP-20-LV-R related relay listing
Technician Note
For directional logic complaints, check loop order and wiring before replacing the detector. Reversed loop inputs or poor loop placement can make a good detector appear to count or trigger backward.
Before Ordering
- Confirm the installation needs two channels or directional logic.
- Verify low-voltage power and connector style.
- Check both loops for continuity, leakage, and proper inductance.
- Confirm loop spacing and travel direction match the intended logic.
- Match pulse/presence and fail-safe/fail-secure settings to the controller.
Important Ordering Warning
Directional logic should support access-control sequencing only. It should not be used to bypass monitored entrapment protection or required gate safety devices.
Professional Advisory
Vehicle detector wiring is part of the gate, door, parking, or access-control safety and command circuit. Do not bypass monitored safety devices or use a detector to defeat required entrapment protection. For high-voltage wiring, cabinet faults, nuisance detection, or unsafe gate movement, use a qualified gate or access-control technician.
Product Questions and Answers
What does the DSP-20LV do that a single-channel detector does not?
It monitors two loop channels and can be configured for two independent channels or directional logic based on loop activation sequence.
Where is directional logic useful?
It is useful in entry/exit lanes, barrier gate systems, and access-control layouts where the controller needs to know travel direction.
Can the loops overlap or be close together?
The DSP-20 uses channel-scanning technology for noise tolerance, but loop layout still needs to follow the job design and manufacturer guidance.
Can this replace a DSP-10 or DSP-15?
Only if the system actually needs a dual-channel detector and the wiring, voltage, and outputs match. It is not a simple one-for-one single-channel replacement.
Why does directional logic trigger incorrectly?
Common causes include reversed loop inputs, poor loop spacing, damaged loops, electrical noise, or using the wrong operating mode.
