Installation Instructions
DS240 and DS241
Long Range Beam Smoke Detectors
1.0Description
The DS240 and DS241 are long range projected beam type smoke detectors which consist of a separate transmitter and receiver. Internal pointability provides coverage flexibility without the need for brackets. Automatic Signal Synchronization and Range Adjustment reduce installation costs. Selectable sensitivity and alarm response time provide installation flexibility.
2.0Specifications
•Operating Voltage: DS240: 18.0 VDC to 32.0 VDC DS241: 10.2 VDC to 15.0 VDC
•Standby Current: DS240: Receiver: 45 mA @ 24.0 VDC Transmitter: 20 mA @ 24.0 VDC
DS241: Receiver: 50 mA @ 12.0 VDC
Transmitter: 20 mA @ 12.0 VDC
•Receiver Alarm
Current:DS240: 60 mA @ 24.0 VDC
DS241: 75 mA @ 12.0 VDC
•Range (distance between transmitter
and receiver): 30 ft to 350 ft (9 m to 107 m)
•Spacing (distance
between systems): Allow no more than 60 ft (18 m) between systems. Sixty foot spacing is confirmed by Underwriters Laboratories, Inc. testing.
•Pointability: Internally pointable optics for ±90° horizontal, and ±10° vertical adjustment.
•Sensitivity:Field selectable for 20, 30, 40, 50, 60, or 70 percent beam obscuration.
•Alarm Contacts: Normally Open contacts rated 1 A,
60 VDC maximum for DC resistive loads. Do not use with capacitive or inductive loads.
•Trouble Contacts: Normally Closed contacts rated 1 A, 60 VDC maximum for DC resistive loads. Do not use with capacitive or inductive loads.
•Aux. Alarm
Contacts:Form "C" (NO, C, NC) contacts rated 1 A, 60 VDC maximum for DC resistive loads. Do not use with capacitive or inductive loads.
• Tamper:Receiver: Access door tamper switch in series with trouble contacts.
Transmitter: Upon cover’s removal, cover tamper switch interrupts transmission.
•System Signaling: Conventional
| with systems that incorporate an alarm | |
| verification feature. | |
• Signal Delay: | Fire: | Selectable 30 sec or 5 sec |
| Trouble: | 20 ± 2 sec |
•Temperature: The storage and operating temperature range is
•Mounting:The units are designed to be mounted to 4 in. (10 cm) square or octagonal electrical boxes (not supplied).
•Listings and
Approvals: | UL | S3019 |
| ULC | CS692 |
| MSFM | Permit #1943 |
| NY City MEA | Acceptance |
| CSFM | |
| FM | Job #OX2A9.AY |
|
|
•Standard
Accessories: DIS2000 Remote Test/Indicator Plate and
Test Cable
•Options: DIS240 Remote Indicator Plate, TK240 Field Test Kit, AL240 Alignment Light, and TC2000 Test Cord.
3.0Principle of Operation
Each DS240 or DS241 beam smoke detector has a separate transmitter and receiver. The transmitter transmits an invisible infrared beam of a specific frequency and intensity. The receiver detects, then measures the beam’s intensity (see Figure 1).
Figure 1 - Infrared Transmission
As the beam is obscured by smoke, the receiver senses a decrease in the signal strength and measures that decrease. The receiver compares the signal level with two preset thresholds: an alarm threshold which is set using the sensitivity switch and a trouble threshold which is preset at approximately 10%. If the signal falls below the alarm threshold for the programmed alarm period, the receiver signals an alarm (see Figure 2).
Figure 2 - Beam Obscuration
If the signal falls below the trouble threshold for more than 20 sec, such as might happen if the beam is blocked by a foreign object, the receiver signals a trouble condition (see Figure 3).
Figure 3 - Beam Blockage
The receiver automatically compensates for the gradual loss of signal due to dust/dirt
A trouble will be indicated at the receiver if the beam strength is increased by more than 20% for greater than 20 sec. Causes include improper initial alignment or the removal of a partial beam blockage at the time of alignment. Preform a
