Hochiki ATJ-EN ESP Analogue Addressable Heat Sensor | Fixed Temperature & Rate of Rise Elements, User Selectable Modes
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Key features
- Switch between fixed temperature and rate of rise elements
- User selectable modes for single or combined detection
- Panel-controlled LED pulsing for commissioning
Downloads
Summary
The Hochiki ATJ-EN is an analogue addressable heat sensor built for jobs where one fixed-sensitivity heat detector won’t cut it. It carries both a Variable Temperature element and a Rate of Rise element, and the control panel decides whether one, the other, or both work together to make the fire decision.
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That flexibility means you can tune detection logic to suit the risk in each area without swapping devices or re-visiting site once it’s commissioned. A plant room prone to gradual heating can run on fixed temperature alone, while a space needing fast response to rapid heat can bring the rate of rise element into play, all set from the panel rather than on the ceiling.
Communication runs over Hochiki’s ESP analogue addressable protocol, with twin LEDs giving 360° visibility of status, green when polling and red in alarm. The panel can also toggle the LEDs between pulsing and non-pulsing, useful when you’re walking a loop during commissioning or fault-finding.
Features
- Dual thermal elements – run fixed temperature, rate of rise, or both together to suit the risk in each area
- User selectable modes – change the active detection logic from the control panel without revisiting the device
- Panel-controlled LED pulsing – toggle pulsing on or off from the panel to suit commissioning or site preference
- Twin 360° status LEDs – green while polling, red in alarm, visible from any approach angle
- Low standby current – 110 µA low power mode and 350 µA quiescent current at 24 VDC ease loop power budgeting
- Broad base compatibility – fits YBN-R/3, YBO-R/SCI, YBO-BS, YBO-BSB and YBN-R/3(SCI) bases across 48-74 mm fixing centres
- SIL Level 2 variants and LPCB/VdS approval – available where projects call for functional safety or third-party approved classes A1, B and C
Video
FAQ
Yes. The control panel selects whether the fixed temperature element, the rate of rise element, or both together make the fire decision, so you can tailor the sensor to the area without fitting a different device. It’s compatible with the YBN-R/3, YBO-R/SCI, YBO-BS, YBO-BSB and YBN-R/3(SCI) bases, covering fixing centres from 48 mm to 74 mm, so you can match it to existing base layouts on a refurbishment. Yes, these functions are controlled from the fire panel over Hochiki’s ESP protocol, and panel compatibility is required to access them. Confirm with the panel manufacturer or Hochiki that your specific control panel supports element selection and pulsing control before relying on it. Allow for 45.5 mA maximum current consumption and 9.1 mA in alarm, excluding any remote indicator, alongside the 350 µA typical quiescent draw at 24 VDC when sizing your loop. The twin LEDs turn red in a fire condition and are visible through 360°, so you don’t need to be directly below the sensor to spot an alarm state while walking the floor. It’s rated IP42 with an operating humidity of 95% RH non-condensing at 40°C, which suits typical indoor commercial environments but isn’t intended for washdown or outdoor exposure. Check the IP rating against the specific area’s conditions before specifying it for anything beyond standard indoor use.Can I run just one heat element instead of both?
Which bases does the ATJ-EN fit?
Do I need a specific control panel to use the selectable modes and LED pulsing?
What loop current should I allow for this sensor?
How will I know the sensor is in alarm from a distance?
Is the ATJ-EN suitable for humid or exposed areas?
Specifications
| Ordering Code | ATJ-EN (Ivory), ATJ-EN(WHT) (White), ATJ-EN(BLK) (Black) |
|---|---|
| Operating Voltage | 17 to 41 VDC |
| Low Power Mode | 110 µA (typ) |
| Quiescent Mode Current | 350 µA (typ) at 24 VDC |
| Maximum Current Consumption | 45.5 mA |
| Alarm Current | 9.1 mA (excluding remote indicator, controlled by CIE) |
| Transmission Method | Digital communications using ESP |
| Operating Temperature Range | -10°C to +50°C |
| Operating Humidity | 95% RH, non-condensing (at 40°C) |
| Storage Temperature Range | -30°C to +60°C |
| Storage Humidity | <80% RH at 70°C |
| Colour Case Material | Ivory, white or black / polycarbonate |
| Weight | 90 g |
| Diameter Height | Ø 100 mm / 45 mm |
| Compatible Bases | YBN-R/3, YBO-R/SCI, YBO-BS, YBO-BSB, YBN-R/3(SCI) (control panel compatibility required) |
| Base Fixing Centres | 48 to 74 mm |
| Approvals | LPCB & VdS classes A1R, BR, CR, A1S, BS and CS; SIL Level 2 approved variants available |
| Ip Rating | BS EN 60529:1992+A2 2013, IP42 |
Downloads
- Datasheet (Adobe PDF)
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