Douglas Krantz - Technical Writer - Describing How It Works

Why do We Map an EST3?

By Douglas Krantz | Descriptions

Why do We Map an EST3?

Why do We Map an EST3?

Greetings Douglas,

My questions are:
  • Why we are doing mapping on an EST3?

  • What are the benefits of mapping?

  • What is the loop card?

Thank You, DH

For the questions, I'll tackle "What is a Loop Card" first.

Loop Card or Loop Controller is an Expander Card in the EST3 System

The loop is the two wires that leave the panel and go to all the detectors and modules in the building. All communications between the panel and the detectors/modules go through the loop. The loop card only controls the devices on one loop of wires.

All fire alarm panels have limits to how many detectors and modules can be on a single loop. With EST, the limit is 125 detectors and 125 module addresses. If there are more devices, there has to be more loops to handle them.

With the EST3, there can be a total of 10 loops that come out of the control panel on the wall. Larger systems can have up to 64 control panels all connected (networked) together. A large hospital here in the metropolitan are here, for instance, has 12 panels, with 42 loops. There are over 3000 smoke detectors, 500 pull stations, 500 smoke detectors, and many other input and output devices.

The loop cards are all separate so that you can buy a small system, that has only one loop, a medium system that has 5 to 10 loops, or a large system that has 15 or more loops. It's the same loop card, just more loop cards or less loop cards in the system.

Mapping is a Fire Alarm Service Function

A "map" is created by fire alarm system each time a detector is removed or replaced, or when the system is first installed. A "map" isn't a blueprint of the building, it is an electrical map showing the location along the wires of the loop for each detector and module. The wires themselves will not be changed unless someone with tools changes the wires. The devices themselves stay in the same place, unless someone deliberately changes a device or its location on the pair of wires.

The whole mapping issue is based on serial numbers. Each smoke detector or module has a separate serial number. There are no duplicate serial numbers anywhere in the world, each serial number is unique.

Serial Number Purpose

For instance, for the firefighters as they arrive at a building to fight a fire, the panel has to be able to display the location of a smoke detector. When a smoke detector goes into alarm, it also identifies itself to the control panel using the serial number. Using the serial number it received from the detector, the panel then looks up in its memory the location message of the detector to help the firefighters find the detector.

The same is true for all the input and output modules connected to the loop. The serial number is used to show the panel what device is communicating, and when the panel is trying to communicate with a specific device, the panel uses the serial number.

Replacing Detectors

When servicing the system, suppose a smoke detector has to be replaced. The new smoke detector has a different serial number from the old smoke detector. The panel has seen that the old smoke detector with its serial number has been removed, and the panel then turns on its trouble light and says that there is trouble with the system.

The new detector has a different serial number. How can the panel tell that the new smoke detector is the replacement smoke detector? How can the panel quit saying there's trouble with the system?

The only way the panel can tell that the new detector with its unique serial number is the replacement for the old smoke detector with its different unique serial number is if the new smoke detector is at the same place on the electrical map as the old detector.

To do this, the panel creates a new electrical map and compares the new map with the old map. The panel looks to make sure the new smoke detector is the same type of detector as the old one. It also makes sure that the new detector is located exactly in the same place on the electrical map as the old detector.

When the panel is satisfied that everything is the same, if the new smoke detector goes into alarm, the panel will display the building location for the firefighters as if the old detector was there.

Without proper mapping of the EST3 fire alarm system, the panel could not tell that a new detector was a direct replacement for an old detector, or if a detector on the 1st floor, for instance, was removed and a different detector was installed on the 3rd floor.

With the mapping function disabled on the EST3, whenever a smoke detector is changed, someone with a computer has to come on site and reprogram the EST3 fire alarm system. With proper mapping, anyone can replace a smoke detector, and the panel will reprogram itself.

That is one benefit of mapping, at a later date, it's easier to replace a smoke detector or a module.

Douglas Krantz
Life Safety
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