APPENDIX
– Normal Terminal Stopping Device
157
Appendix
NTSD
Normal Terminal Stopping Device
Functional Overview:
The drive can be configured to perform a pre-
programmed NTSD slowdown by several
different methods as outlined below.
EXTERNAL:
The car controller or other
elevator controls provide all NTSD detection
functions and modify the speed command
profile to the drive as necessary to perform an
NTS slowdown… OR a logic input is sent to
the drive from external car controller
equipment to tell the drive to disregard other
high speed commands and quickly decelerate
to a pre-programmed low speed.
INTERNAL:
The drive itself monitors 1 or 2
hoistway position logic signals that represent
up to 3 separate physical checkpoint locations
in the hoistway. When one of these hoistway
position logic signals changes state, this
implies that the car has crossed one of the
physical checkpoint locations. The drive then
verifies that the traveling speed at this
particular checkpoint (based on the NTSD
mode and the state of the hoistway position
logic signal(s)) is less than or equal to the pre-
programmed NTSD Threshold speed(s) as it
approaches terminal landings. The drive will
limit the car speed to ensure that it remains at
or below the pre-programmed NTSD Target
Speed [Position “1” is always the location
closest to the landing.] Note that the car
controller has exclusive control of the NTSD
operation when NTSD MODE is set to
External.
In either of the above conditions, the drive may
continue to follow an externally supplied speed
command if it is less than the NTSD TARGET
SPEED as it continues to approach the landing
and will stop when commanded to do so. A
programmable output may be selected to
indicate when an NTS slowdown mode is
active. If serial communications are used, bit 7
of byte 4 will also indicate that an NTS
slowdown is in progress. All of the settings for
the NTSD operating mode, deceleration rate,
slow down target speed and NTSD speed
thresholds are adjustable. To aid internal
NTSD set up, captured speed read-outs are
provided to indicate the traveling speed as the
car passes the hoist way position markers and
changes the status of logic inputs to the drive.
When NTSD logic input signal conditions
indicate that the car is no longer close to the
landing, the drive will return to the original S-
Curve control settings and again follow any
commanded speed. NTSD adjustments may
be used in English or Metric units as
programmed in Menu U3.
Set up and adjustment functions for the NTSD
features are:
Menu C1
– NTSD MODE: External, 1
threshold, 2 thresholds or 3 thresholds to
identify the NTSD operating mode, if any.
Menu C2
– NTSD Input 1 and NTSD Input 2
logic selection identification and location if
used.
Menu C3
– NTSD is active output logic
selection identification if used.
Menu A1
– NTSD Target Speed, NTSD
Threshold 1, NTSD Threshold 2, NTSD
Threshold 3 when used.
Menu A2
– S-Curve Set 4, the pre-set NTS
slow down profile
Menu D1
– Captured speed feedbacks at
NTSD positions 1, 2, and 3, when programmed
to be used by the NTSD Mode selected in C1.
Mode C1: External
NTSD Input
1
NTSD Input
2
Result
Not Used
Not Used
Internal NTSD
function of drive
is not used
1
Normal
Operation
0
Use S-Curve 4 to
decel and run at
NTSD Target
Speed, OR run at a
slower supplied
speed command
Mode C1: 1 Threshold
NTSD Input
1
NTSD Input
2
Result
1
Not Used
Normal
Operation
0
If speed feedback
is greater than
NTSD Threshold 1,
decel using S-
Curve 4, and clamp
the speed
command to be no
greater than NTSD
Target Speed.
.
