Description

What are End of Line Resistors and do I need them ?

Short answer:

End of line resistors (EOLR) are resistors of a specified value that are used to terminate protective loops or zones.

The purpose of EOLR's is to allow the control panel to supervise the field wiring for open or short circuit conditions. How the alarm responds to each depends on the panel as well as system zone programming, but generally speaking, an alarm views an open circuit as a fault or alarm condition, and a short circuit as a trouble or alarm condition (if armed). The purpose of EOLR's is to allow the panel to differentiate between the two conditions by looking for a known resistance.

EOLR's should be installed at the last device on the loop, electrically speaking, and not inside the control, unless special conditions are met. The benefits of EOLR's on protective zones with all concealed wiring is commonly argued by professional installers, as well as EOLR's installed inside the control unit, negating their effectiveness, as well as disabling the EOLR feature and using NC (normally closed) loops for zone definitions. The use of EOLR's is recommended and is particularly important when the field wiring is subject to damage or compromise.

A fire EOLR should always be installed at the last device and never inside the control or across the zone defined as fire, as this is an inherent safety issue.

Some equipment supports Double End of Line Resistors (DEOLR) to further differentiate between conditions that may exist on the loop.

Want to know more about End Of Line Resistors?

FEATURED ARTICLE

What are they, and why are they used?

Where should resistors be placed?

Why does the wiring need to be supervised? How can the circuit become shorted?

If a shorted zone is so unlikely, are resistors really necessary?

Resistors seem like such a sensible idea. Is there any reason NOT to use them, and place them at the end of the line as required?

Is there any way to place the resistor inside the can but still supervise the wiring?

Are there any other ways in which resistors are used?

The GSM SMS Controller-Alarm S**0 S**0 S**0 is a universal GSM Remote Control switch and GSM Alarm Unit.

The GSM SMS Controller-Alarm S**0 S**0 S**0 provides 2/4/8 digital inputs(NC/NO/EOL);

>>>>>>S**0/S**0/S**0 Specifications:

GSM Frequency: Default **0/***0/***0MHz, Optional **0/***0/***0/***0MHz

Power adapter: DC *2V/1.5A Power Current: Max:**0mA   Type :*0mA

SIM Card    :   Supporting 3V SIM Card

GSM Antenna : *0 Ω SMA Antenna interface,

Serial      : USB Port

Input Type   : S**0: 2 Dry Contact, NC,NO,EOL

             S**0: 4 Dry Contact, NC,NO,EOL

             S**0: 8 Dry Contact, NC,NO,EOL

Output Type :  2 Relay Output, **0VAC/3A, Relay inside.

Dimension   : LxWxH **3x*6x*8mm

Backup-Power :    3.7V ***0MAh LI-ION battery

Temperature :   **0°C ~ **0 °C

Humidity    :    Relative humidity *0~*5% (condensation free)

Net Weight  : **0g