Elevator Control System - Part Two

In the previous Topic “Elevator Control System – Part One”, I indicate that the elevator as a control system has a number of components which are:
  1. Inputs. 
  2. Outputs. 
  3. Controllers. 

I explained each one of these components in this previous Topic and Today I will continue explaining the elevator Control system as follows.

You can review the following previous topics for more information and good following.

Discrete control and communication interfaces in elevator Control system:

Under this title, we will find (5) components as follows:

  1. Car Operating Panel COP.
  2. Car top operating station.
  3. Controller Cabinet.
  4. Communications Interface.
  5. Supervisory Control Panel.

1- Car Operating Panel COP 

Car Operating Panel COP

Car operating panel COP is A panel mounted in the car containing the car operating controls keys and buttons as follows:

Car Operating Panel COP Buttons


a- Door-close-button
The door-close-button can be used to close the door immediately after a car call is given, which reduces the waiting time.

b- Door-open-button
The door-open-button can be used to open the door or to hold the door open.
On operating the door-open-button the closing movement will be stopped and the door will be re-opened. After some seconds the door will close.

c- Alarm button
On operating the alarm button the alarm device will be activated and a voice communication with the emergency service established.
The alarm button serves as emergency light which remains active by means of standby-power even in the case of power failure.

d- Fan button
The fan button switches the fan in the car on / off.

e- Overload indicator
The overload indicator gives an optical and / or acoustic signal to indicate that the car is overloaded. If the car is overloaded, it will remain at the floor with doors open.
The signal stops automatically as soon as overload is removed. Then normal operation can be continued.

f- Car position indicator / direction indicator
The car position indicator permits the floor to be read on which the car is located at the moment or displays special information, e.g. inspection operation.

g- Fireman button
Used in the event of a fire in the elevator.

h- Floors button
Used to choose the floor that you want to get him.

i- Instruction plate
Be Stick on the COP to show how to handle passengers in the car lift in case of emergency.

Note: Braille Markings for the COP, Hall Stations and Hall landings are included as standard equipment.

2- Car top operating station 

Car top operating station

Car top operating station provided on some cars for operating the car from the car top. To be used by the elevator technician when servicing the car.

This station should only be operated under the direct supervision of the elevator technician.

3- Controller Cabinet 

Controller Cabinet

The controller cabinets are installed usually in the elevator control room above the hoistway. Their sizes vary with the complexity of the required controls. They should be installed plumb, square and securely fixed in place. Adequate lighting should be provided and the environmental conditions required by manufacturers must be observed like temperature and humidity for example, if the natural ventilation is not good, a forced ventilation of the cabinet should be applied.

4- Communications Interface

The communications interface in the elevator system consists of telephone which is directly connected to a repair person’s phone, which is staffed 24 hours a day. Thus, in the event of an emergency, a user can pick up the phone and will be connected immediately to a repair person, who will be able to assist the user or direct their call to the proper people.

The phone usually placed in a recessed box (phone box) mounted on the cab wall with a hinged cover to hides the phone from view and there are two types of elevator phones as follows:

a- Standard Phone

Standard Phone

Standard “rotary “type phone can be mounted on the cab wall or in a phone box.

b- Hands Free ADA Phone

Hands Free ADA Phone

A special programmable speaker phone that just requires the touch on one button dial a number.

5- Supervisory Control Panel 

Supervisory Control Panel

This is a monitoring panel located in the security room that displays the status of all the elevators or escalators operating in the building including flooring location, traveling direction, in/out-of service etc.

Special operating modes for Elevator control system

1- Anti-Crime Protection (ACP)
Anti-Crime Protection will force each car to stop at a pre-defined landing and open its doors. This allows a security guard or a receptionist at the landing to visually inspect the passengers. The car stops at this landing as it passes to serve further demand.

2- Up peak (MIT)
During Up Peak mode (also called Moderate Incoming Traffic), elevator cars in a group are recalled to the lobby to provide expeditious service to passengers arriving at the building, most typically in the morning as people arrive for work or at the conclusion of a lunch-time period.

Elevators are dispatched one-by-one when they reach a pre-determined passenger load, or when they have had their doors opened for a certain period of time. The next elevator to be dispatched usually has its hall lantern or a "this car is leaving next" sign illuminated to encourage passengers to make maximum use of the available elevator system capacity.

The commencement of Up Peak may be triggered by a time clock, by the departure of a certain number of fully loaded cars leaving the lobby within a given time period, or by a switch manually operated by a building attendant. 

3- Down peak
During Down Peak mode, elevator cars in a group are sent away from the lobby towards the highest floor served, after which they commence running down the floors in response to hall calls placed by passengers wishing to leave the building. This allows the elevator system to provide maximum passenger handling capacity for people leaving the building.

The commencement of Down Peak may be triggered by a time clock, by the arrival of a certain number of fully loaded cars at the lobby within a given time period, or by a switch manually operated by a building attendant. 

4- Sabbath service (SHO)
In areas with large populations of observant Jews or in facilities catering to Jews, one may find a "Sabbath elevator". In this mode, an elevator will stop automatically at every floor, allowing people to step on and off without having to press any buttons. This prevents violation of the Sabbath prohibition against operating electrical devices when Sabbath is in effect for those who observe this ritual.

However, Sabbath mode has the side effect of wasting considerable amounts of energy, running the elevator car sequentially up and down every floor of a building, repeatedly servicing floors where it is not needed. For a tall building with many floors, the car must move on a frequent enough basis so as to not cause undue delay for potential users that will not touch the controls as it opens the doors on every floor up the building.

5- Independent service (ISC)
Independent service is a special service mode found on most elevators. It is activated by a key switch either inside the elevator itself or on a centralized control panel in the lobby. When an elevator is placed on independent service, it will no longer respond to hall calls. (In a bank of elevators, traffic is rerouted to the other elevators, while in a single elevator, the hall buttons are disabled). The elevator will remain parked on a floor with its doors open until a floor is selected and the door close button is held until the elevator starts to travel. Independent service is useful when transporting large goods or moving groups of people between certain floors.

6- Inspection service (INS)
Inspection service is designed to provide access to the hoistway and car top for inspection and maintenance purposes by qualified elevator mechanics. It is first activated by a key switch on the car operating panel usually labeled 'Inspection', 'Car Top', 'Access Enable' or 'HWENAB'.

When this switch is activated the elevator will come to a stop if moving, car calls will be canceled (and the buttons disabled), and hall calls will be assigned to other elevator cars in the group (or canceled in a single elevator configuration). The elevator can now only be moved by the corresponding 'Access' key switches, usually located at the top-most (to access the top of the car) and bottom-most (to access the elevator pit) landings. The access key switches will allow the car to move at reduced inspection speed with the hoistway door open. This speed can range from anywhere up to 60% of normal operating speed on most controllers, and is usually defined by local safety codes.

Elevators have a car top inspection station that allows the car to be operated by a mechanic in order to move it through the hoistway. Generally, there are three buttons — UP, RUN, and DOWN. Both the RUN and a direction button must be held to move the car in that direction, and the elevator will stop moving as soon as the buttons are released. Most other elevators have an up/down toggle switch and a RUN button. The inspection panel also has standard power outlets for work lamps and powered tools.

7- Fire service mode (EFS)
Depending on the location of the elevator, fire service code will vary state to state and country to country. Fire service is usually split up into two modes: Phase One and Phase Two. These are separate modes that the elevator can go into.

Phase one mode is activated by a corresponding smoke sensor or heat sensor in the building. Once an alarm has been activated, the elevator will automatically go into phase one. The elevator will wait an amount of time, then proceed to go into nudging mode to tell everyone the elevator is leaving the floor. Once the elevator has left the floor, depending on where the alarm was set off, the elevator will go to the Fire Recall Floor. However, if the alarm was activated on the fire recall floor the elevator will have an alternate floor to recall to. When the elevator is recalled, it proceeds to the recall floor and stops with its doors open. The elevator will no longer respond to calls or move in any direction. Located on the fire recall floor is a fire service key switch. The fire service key switch has the ability to turn fire service off, turn fire service on or to bypass fire service. The only way to return the elevator to normal service is to switch it to bypass after the alarms have reset.

Phase two mode can only be activated by a key switch located inside the elevator on the centralized control panel. This mode was created for firefighters so that they may rescue people from a burning building. The phase two key switch located on the COP has three positions: off, on, and hold. By turning phase two on, the firefighter enables the car to move. However, like independent service mode, the car will not respond to a car call unless the firefighter manually pushes and holds the door close button. Once the elevator gets to the desired floor it will not open its doors unless the firefighter holds the door open button. This is in case the floor is burning and the firefighter can feel the heat and knows not to open the door. The firefighter must hold door open until the door is completely opened. If for any reason the firefighter wishes to leave the elevator, they will use the hold position on the key switch to make sure the elevator remains at that floor. If the firefighter wishes to return to the recall floor, they simply turn the key off and close the doors.

Fire Service is for emergency use only, although fire service keys can be purchased on eBay, and other websites. Only trained responders should use this feature, and it is by no means a safe way to escape from a burning building.

8- Medical emergency/'Code Blue' service (EHS)
Commonly found in hospitals, Code Blue service allows an elevator to be summoned to any floor for use in an emergency situation. Each floor will have a 'Code Blue' recall key switch, and when activated, the elevator system will immediately select the elevator car that can respond the fastest, regardless of direction of travel and passenger load. Passengers inside the elevator will be notified with an alarm and indicator light to exit the elevator when the doors open.

Once the elevator arrives at the floor, it will park with its doors open and the car buttons will be disabled to prevent a passenger from taking control of the elevator. Medical personnel must then activate the Code Blue key switch inside the car, select their floor and close the doors with the door close button. The elevator will then travel non-stop to the selected floor, and will remain in Code Blue service until switched off in the car. Some hospital elevators will feature a 'hold' position on the Code Blue key switch (similar to fire service) which allows the elevator to remain at a floor locked out of service until Code Blue is deactivated.

9- Emergency power operation (EPO)
Many elevator installations now feature emergency power systems which allow elevator use in blackout situations and prevent people from becoming trapped in elevators.

When power is lost in a traction elevator system, all elevators will initially come to a halt. One by one, each car in the group will return to the lobby floor, open its doors and shut down. People in the remaining elevators may see an indicator light or hear a voice announcement informing them that the elevator will return to the lobby shortly. Once all cars have successfully returned, the system will then automatically select one or more cars to be used for normal operations and these cars will return to service. The car(s) selected to run under emergency power can be manually overridden by a key or strip switch in the lobby. In order to help prevent entrapment, when the system detects that it is running low on power, it will bring the running cars to the lobby or nearest floor, open the doors and shut down.

Control Room Electromechanical Requirements

  • Must provide one dedicated phone line per elevator. 
  • Must be properly vented to maintain a temperature between 32° and 104° F. 
  • Door must be self-closing and self-locking with group 2 locking devices. 
  • Provide suitable lighting in control room with switch located within 18" of lock jamb side of door. 
  • Provide GFCI convenience outlet. 
  • Provide 3-phase power supply with circuit breaker or fused disconnect per contract requirements. Must be lockable in the OPEN position. The feeder wire should be connected to the controller and properly grounded per N.E.C. 
  • Provide 120-volt, 15-amp, single-phase power supply with a fused disconnect or circuit breaker wired to the elevator controller. 

This Topic will be the last one that explains the Traction elevator components and In the next Topic, I will explain the Hydraulic Elevator Components. So, please keep following.

Note: these topics about elevators in this course EE-1: Beginner's electrical design course is an introduction only for beginners to know general basic information about elevators as a type of Power loads. But in other levels of our electrical design courses, we will show and explain in detail the Elevator Loads Estimation calculations. 


  1. Dear Sir,
    Thank you for this large and important information about elevator system.
    however I would like to know more about the Fire-man elevator.
    In case we have a fire-man elevator in a certain project, how would it be differ from the ordinary passenger elevator system ?
    In other words, the fire-man elevator will have all its wires; cables and travelling cable as fire rated cables. Therefore, when doing our elevator inspection missions on site, and faced a fire-man elevator system, should it be based on the ordinary french norm EN 81-1 or should it have another proper norm that we should respect during ou rinspection ?

    thank you & best regards.
    Bechir Hasbani.

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