Diablo Controls RK-3R Three Position Card Rack with Relay
The Diablo Controls RK-3R is a multi-position detector rack used when one cabinet needs several plug-in vehicle detector modules in a clean, serviceable layout. It accepts up to three compatible plug-in detectors and brings wiring to terminal blocks, helping installers organize loop detector circuits for access lanes, barrier gates, parking control systems, and commercial gate operators. The RK-3R is useful where a site has multiple loop functions, such as a free-exit loop, reverse/safety loop, shadow loop, presence loop, or parking count loop. The rack itself does not sense vehicles; the installed detector modules and loops do that work. Its job is to provide the physical rack, wiring interface, and relay interface where supported. Compatibility depends on detector pinout, relay requirements, input wiring, cabinet space, and the system's loop design.
Compatible With
- Up to three compatible Diablo Controls plug-in vehicle detector modules where the RK-3R rack format is specified.
- Gate operator and barrier gate cabinets using multiple loop detector functions.
- Parking control and access-control systems with multiple detector inputs or lane functions.
- Installations needing terminal block wiring for free exit, safety/reverse, shadow, presence, count, or lane-control loops.
- Sites replacing an existing RK-3R rack when the detector module style and wiring layout match.
- Related to RK-1R single-position rack but designed for up to three detector positions.
- Not a complete detector system and not a universal replacement for all rack, 11-pin socket, or detector formats.
Features & Specifications
| Manufacturer | Diablo Controls |
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| Product Type | Three Position Card Rack with Relay |
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| Part Number | RK-3R / DSP-RK-3R |
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| Application | Mount and interface up to three plug-in vehicle detectors |
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| Positions | Up to three detector positions |
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| Output Interface | Relay interface where supported |
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| Wiring | Terminal block field wiring |
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| Common Use | Multiple loop functions in gate, parking, and access-control cabinets |
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| Related Product | RK-1R single-position rack |
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| Notes | Detector modules and loops are separate unless sold in a kit |
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Also Known As / Related Part Numbers
- RK-3R
- RK-3-R
- RK3R
- DSP-RK-3R
- Diablo RK-3R card rack
- three position detector rack
- RK-1R - related single-position rack
- Diablo plug-in detector rack
Technician Note
Label each loop and output before removing an existing RK-3R. Mixed-up loop wires can make a gate open when it should reverse, count vehicles incorrectly, or ignore the intended safety/reverse input.
Before Ordering Checklist
- Confirm the cabinet requires three detector positions or a matching RK-3R replacement.
- Verify each detector module is compatible with the rack.
- Document loop inputs and output terminals before removal.
- Confirm relay/contact behavior needed by each controller input.
- Check cabinet space and wire routing before installation.
Professional Advisory
Multi-loop cabinets can be difficult to troubleshoot because several detectors may interact. A qualified technician should verify loop function, relay behavior, and gate response after any rack or detector replacement.
Important Ordering Warnings
- The RK-3R is not a vehicle detector without detector modules and loops.
- Do not interchange loop wires or output terminals during replacement.
- Different detector modules can have different output behavior even when they fit the rack physically.
Product Q&A
How many detectors does the RK-3R hold?
It is designed to accept up to three compatible plug-in vehicle detectors.
Does the RK-3R include the detector modules?
The rack is the mounting and wiring interface. Detector modules are separate unless the listing specifically includes them.
What systems commonly use it?
It is commonly used in gate, barrier, parking, access-control, and vehicle detection cabinets with multiple loop functions.
Can I replace an RK-1R with an RK-3R?
Only if the cabinet space, wiring layout, detector style, and required number of detector positions support the change.
Why are terminal labels important?
Each loop and output may control a different function, such as exit, reverse, shadow, or count. Miswiring can create unsafe or unreliable operation.
