Bosch Power Tools DS240, DS241 specifications Description, Specifications, Principle of Operation

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 4-wire system. Not for use

	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 -22°F to +130°F (-30°C to +54°C). For UL Listed installations, the range is +32°F to +130°F (0°C to +54°C).

•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 #MEA274-93-E
	CSFM	#7260-1062:106
	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 build-up on the cover. After 50 percent of the signal is lost, the receiver will indicate a trouble. When the dust/dirt build-up is cleaned or the blockage is removed, the detector automatically goes back to its normal operation level.

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 fine-tune alignment (see Section 7.3 Fine Tune Alignment on page 6).

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