LINET Wissner-Bosserhoff ELEGANZA 4, Service Manual, Page: 9 / 57

D9S001GE4-0101 9/ 57
3.1.5.2 STOP button located on the ACP panel
The main STOP button immediately stops all movements of the bed (undesirable movement) and deactivates GO if
positioning is not permitted or during failure of electrical components. A 10 k
Ω
resistor is connected in parallel to the
STOP button inside the keypad. The electronics of the system detect the correct connection of the resistor (connection
of keypad and functionality of the STOP button). Its interruption (error in keypad, faulty resistor, cable...) is signalled
by an intermittent tone from the control unit. Without correct connection of ACP controller to the resistors, this function
after activation with the GO button is only active for 5s.
3.1.5.3 GO button located on the ACP panels, the handset, and side rails
All the control functions are conditional on the GO button being pressed (only the CPR and STOP button do not
require the GO button to be pressed). When GO is pressed, the control system is activated for 3 minutes (except
during fault of the STOP circuit
– described above). When any function is pressed for more than 2 seconds, the button
is released for an extension of the GO period by another 3 minutes. When a function is pressed for less than 2 seconds,
the original 3 minutes remains. After 3 minutes from the previously selected function, the control electronics are
deactivated and any further function is conditional on the GO button being pressed again. Pressing the GO button is
only valid if no other control button has been pressed at the same time. The use of the GO button significantly limits
the possibility of accidental movement of the bed during a fault or from unintentional pressing of controllers.
3.1.5.4 Simultaneous pressing of any two buttons
The control unit is issued with the function for recognizing two pressed buttons at the same time. When two buttons
are pressed at the same time, control unit blocks function. Unblocking is automatic after all presses have been released
(including the error ones).
3.1.5.5 RC circuits
– protection against shorting and spontaneous movement
An RC circuit is installed in all the analogue control elements connected to the ACP control unit (ACP, handset,
mobilift, foot controller). The value of the RC circuit resistor is 390
Ω.
If the function is not active, the circuit resistance
is infinite as standard. When any function is pressed, the resistance of the circuit is 390
Ω
, the function is detected as
valid and it begins. If a short is present in the circuit of the button, the resistance drops below 200
Ω
, the control unit
detects the function as invalid and positioning does not occur. The RC circuit serves to prevent spontaneous
movements of the bed caused by a short in the wiring.
3.1.5.6 Measuring leaks
The control unit is capable of measuring leaks in the individual controllers in a range of
kΩ.
If resistance is detected in any of the controllers, it is signalled by all the lock LEDs flashing, the control unit always
permitting one movement of the bed after the STOP button is pressed. Information about the leak is recorded
simultaneously in the permanent memory of the control unit.
3.1.5.7 Positioning function locks
The positioning function locks have an electronic design and their current condition is always saved in an EEPROM
type memory. If they possess a fault , this condition is signalled by the relevant lock flashing its LED.
0 < 200
Ω - Short
≥ 1 kΩ - Leakage
390
Ω - OK