FLM-I 420-S - Fire alarm system BOSCH - Free user manual and instructions

Product Type	Short Circuit Isolator for fire alarm systems
Model	FLM-I 420-S
Input Voltage	15 V DC to 33 V DC
Max Current Consumption	< 0.4 mA during initialization, < 0.25 mA after initialization
LSN/Address Setting	3 rotary switches for classic or improved LSN mode, automatic or manual addressing (addresses 0-254)
Connections	6 threaded clamps for LSN (b1+, a-, b2+) and 3 free terminals for looping aux voltage and shielding
Housing Material	Isolator module: PPO (Noryl); Surface-mount housing: ABS/PC blend
Color	Isolator module: Off-white (RAL 9002); Housing: Signal white (RAL 9003)
Dimensions (H x W x D)	Approx. 126 x 126 x 71 mm (4.96 x 4.96 x 2.8 in)
Weight	Approx. 150 g (5.3 oz)
Operating Temperature	-20 °C to 50 °C (-4 °F to 122 °F)
Storage Temperature	-25 °C to 85 °C (-13 °F to 176 °F)
Relative Humidity	< 96%
Protection Class	IP54 (IEC 60529)
Equipment Class	Class III (IEC 60950)
Certifications	EN54-17:2005; VdS G 207045 (Germany)
Compatible Fire Panels	FPA-5000 Modular, FPA-1200 with LSN improved technology
Mounting	Surface-mounted housing or DIN rail (with included adapter)
Cable Entry	2 x 2 pre-punched for up to 21 mm/34 mm conduits; 2 x 4 rubber bushes for cables up to 8 mm; additional ducts on base
Included Accessories	Short Circuit Isolator with surface-mounted housing, DIN rail adapter
Function	Isolates alarm zones with short circuits; preserves LSN loop functionality via two integrated isolators; supports T-tapping and up to 254 LSN-improved elements per loop

Frequently Asked Questions - FLM-I 420-S BOSCH

What is the purpose of the FLM-I 420-S Short Circuit Isolator?

The FLM-I 420-S isolates alarm zones where a short circuit has occurred, preserving the functionality of the remaining LSN network. It uses two integrated isolators to maintain loop operation during a fault.

How do I set the address on the FLM-I 420-S?

Address is set using three rotary switches. For classic LSN mode, set to CL 0 0. For improved LSN mode with automatic addressing, set to 0 0 0. For manual addressing (1-254), set the switches to the desired address. Manual addressing supports T-tap systems.

What are the power requirements for this isolator?

The FLM-I 420-S operates on 15 V DC to 33 V DC supplied via the LSN loop. Maximum current consumption is less than 0.4 mA during initialization and less than 0.25 mA after.

Can the FLM-I 420-S be mounted on a DIN rail?

Yes, it comes with a DIN rail adapter for mounting on a standard DIN rail, in addition to the surface-mounted housing.

What is the difference between classic and improved LSN mode?

Classic LSN mode uses the original protocol. Improved LSN mode supports flexible network structures (including T-tapping), unshielded cable, and up to 254 devices per loop or stub line. The FLM-I 420-S can be configured for either mode.

Is the FLM-I 420-S compatible with all Bosch fire panels?

It is compatible with Bosch fire panels that support LSN improved technology, such as the FPA-5000 Modular and FPA-1200. Check your panel's specifications for LSN improved compatibility.

What certifications does the FLM-I 420-S have?

It complies with EN54-17:2005 and has VdS approval (Germany) with certificate number G 207045 for both FLM-I 420-S and FLM-I 420-D.

What is the maximum number of devices that can be connected on one loop?

In improved LSN mode, up to 254 LSN-improved elements can be connected per loop or stub line, including the isolators.

How should I wire the FLM-I 420-S for a T-tap configuration?

For T-tap, connect the LSN loop to b1+ and b2+ terminals. The example in the manual shows a typical T-tap wiring where the isolator is placed between two LSN segments. Ensure manual addressing is used (address 1-254).

What are the environmental limits for operating the FLM-I 420-S?

It operates from -20 °C to 50 °C (-4 °F to 122 °F) and can be stored from -25 °C to 85 °C (-13 °F to 176 °F). Maximum relative humidity is 96%. It is IP54 rated for dust and water splash protection.

USER MANUAL FLM-I 420-S BOSCH

FLM-I 420-S Short Circuit Isolator

White rectangular electronic device with three black buttons and a small square symbol on its side (no visible text or labels)

The Short Circuit Isolator isolates alarm zones in which a short circuit has occurred. This means the functionality of the remainder of the network remains preserved.

System Overview

Description Connector

b1+ / a- / b2+ LSN

N/A (3 x) free terminals, e.g. for looping through ext. auxiliary voltage and for shielding

• Rotary switch for automatic and manual address setting
• Preservation of LSN loop functions in the event of a short-circuit by two integrated isolators
  ▶ Power supply via LSN
  ▶ Three free screw terminals

Functions

Features of improved LSN

The interface modules in the 420 series offer all the features of improved LSN technology:

• Flexible network structures including T-tapping without additional elements
• Up to 254 LSN-improved elements per loop or stub line
  • Unshielded cable can be used

Address switch (rotary switch)

The address of the Short Circuit Isolator is set using the rotary switches.

The following settings are possible:

0 0 0 Loop/stub in LSN mode improved version with automatic addressing (T-tap system not possible)

0 0 1 - 254 Loop/stub/T-tap system in LSN mode improved version with manual addressing

CL 0 0 Loop/stub in classic LSN mode

Configuration

The Short Circuit Isolator isolates alarm zones in which a short circuit has occurred. The following illustrations show typical configurations of the isolator module.

Wiring example: Isolation of separate floors

graph TD
    A["LSN1"] -->|b+| B["LSN2"]
    B -->|a-| C["LSN"]
    B -->|b+| D["LSN"]
    D -->|a-| E["LSN"]
    E -->|b+| F["LSN"]
    F -->|b-| G["LSN"]
    G --> H["LSN"]
    H --> I["II"]
    I --> J["FLM-I 420-S"]
    J --> K["III"]
    J --> L["II"]
    J --> M["II"]
    J --> N["I"]

Pos. Description

1 Fire panel

I, II, III Floors

Typical wiring in a T-Tap

graph LR
    A["LSN"] --> B["b1+"]
    B --> C["1"]
    C --> D["b2+"]
    D --> E["1"]
    E --> F["b1+b1b2+b2+"]
    F --> G["FLM-I 420-SFLM-I"]
    G --> H["LSN"]
    I["a-a-y"] --> F
    J["b1+"] --> G
    K["a-"] --> G

Pos. Description

1 Alarm zone / device group with LSN elements

Certifications and Approvals

Complies with EN54-17:2005

Region Certification

Germany VdS G 207045 FLM-I 420-S; FLM-I 420-D

Installation/Configuration Notes

- National standards and guidelines must be taken into account during the planning stage.

• The surface-mounted housing has two cable ducts on opposite sides:
• 2 x 2 pre-punched for diameter up to 21 mm/to 34 mm (for conduits)
• 2 x 4 rubber bushes for inserting cables with diameters of up to 8 mm.
• In addition, there are cable ducts on the base of the surface-mounted housing:
• 1 x pre-punched cable ducts for diameter up to 21 mm (for conduits)
• 2 x 4 rubber bushes for inserting cables with diameters of up to 8 mm.
• Connectable to the fire panels FPA-5000 Modular and FPA-1200 with LSN technology improved version.

Parts Included

Qty. Components

1 Short Circuit Isolator with surface-mounted housing.
1 DIN rail adapter

Note Alternatively to the use of the surface-mounted housing, the Isolator can be mounted on a DIN rail with the included adapter.

Technical Specifications
Electrical

Input voltage	15 V DC to 33 V DC
Max. current consumption
• During initialization	< 0.4 mA
• Following the initializa-tion	< 0.25 mA

Mechanics

LSN/Address setting	3 rotary switches for
	• Mode LSN classic or LSN improved version
	• Automatic or manual addressing
Connections	6 threaded clamps
Housing material
• Isolator module	PPO (Noryl)
• Surface-mount housing	ABS/PC-Blend
Housing color
• Isolator module	Off-white, similar to RAL 9002
• Surface-mount housing	Signal white, RAL 9003
Dimensions	Approx. 126 x 126 x 71 mm(4.96 x 4.96 x 2.8 in.)
Weight	Approx. 150 g (5.3 ounces)

Environmental conditions

Permitted operating temperature	-20 °C to 50 °C(-4°F to 122°F)
Permitted storage temperature	-25 °C to 85 °C(-13°F to. 176°F)
Permitted relative humidity < 96%
Classes of equipment as per IEC 60950	Class III equipment
Protection class as per IEC 60529	IP 54

Ordering Information

FLM-I 420-S Short Circuit Isolator	FLM-I 420-S
for the isolation of alarm zones in which a short circuit has occurred.

Accessories

FLM-IFB126-S Surface-mounted Housing as retainer for the interface modules series 420 type DIN rail (-D) or spare housing for type surface-mount (-S)

FLM-IFB126-S

Americas:

Bosch Security Systems, Inc.

130 Perinton Parkway

Fairport, New York, 14450, USA

Phone: [phone]

Fax: [phone]

[e-mail]

www.boschsecurity.us

Europe, Middle East, Africa:

Bosch Security Systems B.V.

P.O. Box 80002

5600 JB Eindhoven, The Netherlands

Phone: [phone]

Fax: [phone]

[e-mail]

www.boschsecurity.com

Asia-Pacific:

Robert Bosch (SEA) Pte Ltd, Security Systems

11 Bishan Street 21

Singapore 573943

Phone: [phone]

Fax: [phone]

[e-mail]

www.boschsecurity.com

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