Overview
The HAD mode (Hoistway Access Detection) is an access detection operation in the shaft for the safety of maintenance technicians.
The objective is to prevent the risk of injury in case technicians do not correctly perform the operations for accessing the top of cabin / pit bottom.
General requirements
- The HAD mode, once activated, must not be reset by disconnecting the main power supply of the system.
- The state of the HAD mode must be stored in the non-volatile memory of the control panel and maintained even in the event of a power failure. This means that in case of power loss during the HAD mode, when power is restored, the system must resume in this mode.
- The HAD mode must only be reset by activating the devices described in the “Acronyms list” below.
- Any interruption of the safety circuit must stop the HAD operation, but not reset it. All safety conditions of the system must be respected during the execution of this operation.
Acronyms list
| General acronym | DMG acronym | Description |
|---|---|---|
| ERO | PME | Emergency Rescue Operation: Emergency button panel inside the controller |
| PES | STOP (SE1 safety chain point) | Pit Emergency Stop: STOP button at the bottom of the pit |
| TCI | REV1 signal | Top Car Inspection: Inspection panel on the top of cabin |
| TES | STOP (SE2 safety chain point) | Top Emergency Stop: STOP button on the top of cabin |
Description of the HAD mode, possible cases and corresponding system behavior.
Case 1 – Entry into the shaft
– Elevator cabin in motion –
- If a floor door is opened while the cabin is in motion, the cabin will immediately stop due to the opening of the safety chain.
Warning: With the cabin in motion during normal operation, it is not allowed for the cabin door to be open.
Access to the shaft is detected (and the HAD mode is activated) only if a floor door is open for more than 4 seconds. - After the floor door closes, the cabin will move at low speed toward the nearest served floor, away from an extreme floor.
In configurations with only 2 stops, the system must go to the lowest extreme floor. - All floor and cabin calls are canceled and not assigned.
- New floor and cabin calls are not allowed.
- Once the disembarking floor is reached, the doors must open (following the normal operation behavior).
- At the end of the predefined time period (open-door dwell time), the cabin must close the doors, allowing reopening only through the door open button.
- While the elevator is not operational at the disembarking floor, with the HAD operation activated:
– The re-leveling is active;
– The door open button is active;
– Floor and cabin calls are inhibited. - The system must remain non-operational at the disembarking floor until the HAD mode is reset.
- The HAD mode must be interrupted only:
– From the activation of TCI or ERO or PES, the elevator will then be available for the ‘inspection’ mode; there is also a 4-second delay for deactivation (for example, with HAD active, if the stop is opened and immediately closed, the elevator will remain in the HAD operation).
– Alternatively, from a specific reset in the controller (Menu > Faults > reset HAD), the elevator will return to being available for ‘normal’ operation modes.
Multiplex elevator groups
When an elevator in the group enters HAD mode:
- all existing floor calls for that elevator must be reassigned to another cabin in the group;
- new floor calls must not be assigned to that cabin;
- any scheduled calls from the COP (Car Operating Panel) are cancelled.
In practice, the elevator with HAD mode active cannot service floor calls or calls from the cabin.
– Elevator cabin stopped at the floor –
- With the cabin empty and stopped at the floor awaiting to enter service, if a floor door is open for more than 4 seconds (see door types), HAD mode must be activated.
- All floor and cabin calls are cancelled and not assigned.
- No new floor or cabin calls are allowed.
- All call buttons must be disabled; the door open button must remain active.
- HAD mode must only be interrupted when:
– From the activation of TCI or ERO or PES, the elevator will then be available for the ‘inspection’ mode; there is also a 4-second delay for deactivation (for example, with HAD active, if the stop is opened and immediately closed, the elevator will remain in the HAD operation).
– Alternatively, from a specific reset in the controller (Menu > Faults > reset HAD), the elevator will return to being available for ‘normal’ operation modes.
Multiplex elevator groups
When an elevator in the group enters HAD mode:
- all existing floor calls for that elevator must be reassigned to another cabin in the group;
- new floor calls must not be assigned to that cabin;
- any scheduled calls from the COP (Car Operating Panel) are cancelled.
In practice, the elevator with HAD mode active cannot service floor calls or calls from the cabin.
Case 2 – Exit from the shaft
If the floor door is kept open for more than 4 seconds after the deactivation of PES, TCI, or TES, the HAD mode is activated (see Case 1 – Entry into the shaft / Elevator cabin in motion).
Features of hydraulic systems
- After the doors close, the countdown for the automatic return to the lowest extreme floor must begin (within 15 minutes, according to EN81.__).
- The automatic return to the lowest extreme floor must occur at low speed.
Diagnostic and signaling tool
In case the operation is activated, the fault 56 (HAD fault) will be recorded in the controller in the Faults menu.
The additional code indicates which point in the safety chain has been opened:
- Code 4 = Preliminary (in case of hinged doors)
- Code 5 = Floor locks
Exclusion of detection
In case the cabin is stopped at a floor, the controller can detect the potential opening of a floor door at another floor only if the door operators are equipped with limit switches (to verify that the cabin door is closed).
It is important to note that the purpose of the operation is to ensure that the cabin is not stopped at another floor. Before opening the doors to access the shaft, the technician must ensure that no one is inside (calls the cabin, verifies that it is empty, and performs a procedure to access the top of cabin).
The function is compatible with the possible absence of the door operator in the cabin; in these cases, the condition of the limit switch monitor is excluded, so detection can only occur if the cabin is out of level.
Types of doors
The operation has been tested with regulated door operators.
The functionality is compatible with semi-automatic door operators (in these cases, HAD detection is not possible while the cabin is stopped at a floor, as these doors typically remain open).
The functionality is compatible with manual/absent doors in the cabin and at the floor (these cases also exclude the possibility of detection while the cabin is stopped at another floor).
Controller parameter setting
The operation can be activated from the following parameter:
Menu > Func.Special >
…
“Shaft protection”
| Value | HAD | SCS (*) |
|---|---|---|
| No | X | X |
| Type 6 | X | O |
| Type 21 | O | X |
| Type 22 | O | O |
(*) SCS (Safety Contact Shunt) – For EN81.20 systems, detection of the presence of jumpers on the door safety contacts is required.
Controller behavior in case of HAD detection
In case of HAD detection, the controller enters the “Anti-drift” state, indicated by a blue LED.
In this state, no calls are accepted, and any new button presses (cabins/floors) are not processed.
If the cabin is out of level, the controller attempts to move the cabin to the nearest floor at low speed; if the cabin is already at a floor, it will not be moved (unless the return to the lowest floor, characteristic of Hydraulic elevators, is activated).
If the controller is powered off while the HAD operation is active, it will automatically resume upon reactivation of the controller.
To exit the HAD state (Antideriva state), the following actions are required:
- Open the STOP in the pit (SE1 point of the safety chain) for more than 4 seconds.
- Open the STOP on the top of cabin (SE2 point of the safety chain) for more than 4 seconds.
- Activate the TOC INSPECTION selector for more than 4 seconds.
- Activate the PME selector for more than 4 seconds
- Perform a specific reset from the Playpad (Menu > Faults > reset HAD).
Note: The activation of the entire safety chain (SE0 point of the safety chain), for example by opening the DIS contact (circuit breaker), does not affect the HAD operation; typically located in the machine room (and thus near the controller), the HAD operation can be exited using one of the two methods (d) or (e) from the previous list.
