Danfoss VLT FC 302 Operating Instructions Manual page 65

Programming
[23] Set-up Select set-up select bit 0 or select set-up select
select bit bit 1 to select one of the 4 set-ups. Set
0 0-10 Active Set-up to multi set-up.
[24] Set-up (Default digital input 32): Same as [23] Set-up
select bit select bit 0.
1
[26] Precise Sends an inverted stop signal when the precise
stop inv. stop function is activated in 1-83 Precise Stop
Function.
Precise stop inverse function is available for
terminals 18 or 19.
[27] Precise Use when [0] Precise ramp stop is selected in
start, stop 1-83 Precise Stop Function.
Precise start, stop is available for terminals 18
and 19.
Precise start ensures that the rotor angle from
standing still to reference is the same for each
start (for same ramp time, same setpoint). This
is the equivalent to the precise stop where the
angle that the rotor turns from reference to
standstill is the same for each stop.
When using for 1-83 Precise Stop Function [1] or
[2]:
The frequency converter needs a precise stop
signal before the value of 1-84 Precise Stop
Counter Value is reached. If this value is not
supplied, the frequency converter does not stop
when the value in 1-84 Precise Stop Counter
Value is reached.
A digital input triggers precise start, stop and is
available for terminals 18 and 19.
[28 Catch up Increases reference value by percentage
] (relative) set in 3-12 Catch up/slow Down Value.
[29] Slow Reduces reference value by percentage
down (relative) set in 3-12 Catch up/slow Down Value.
[30] Counter Precise stop function in 1-83 Precise Stop
input Function acts as Counter stop or speed
compensated counter stop with or without
reset. The counter value must be set in
1-84 Precise Stop Counter Value.
[31] Pulse Edge triggered pulse input counts the number
edge of pulse flanks per sample time. This number
triggered gives a higher resolution at high frequencies,
but is not as precise at lower frequencies. Use
this pulse principle for encoders with low
resolution (30 ppr, for example).
Pulse
Sample time
Illustration 6.10 Pulse vs. Sample Time
[32] Pulse Time-based pulse input measures the duration
time- between flanks. This number gives a higher
based resolution at lower frequencies, but is not as
precise at higher frequencies. This principle has
a cut-off frequency that makes it unsuited for
MG37A202
Operating Instructions
[34] Ramp bit
0
[35] Ramp bit
1
Preset ramp bit
Ramp 1
Ramp 2
Ramp 3
Ramp 4
Table 6.7
[40] Latched
Precise Start
[41] Latched
Precise Stop
inverse
[51] External
interlock
[55] DigiPot
Increase
[56] DigiPot
Decrease
Danfoss A/S © Rev. 2014-07-29 All rights reserved.
encoders with low resolutions (30 ppr) at low
speeds.
Speed [rpm] Speed [rpm]
a Time[sec] b Time[sec]
a Low encoder resolution
b Standard encoder resolution
Illustration 6.11 Encoder Resolution
Comparison
Pulse
Timer
Sample time
Time counter
Time Start Read Timer: Read Timer:
20 timer tides 20 timer tides
Illustration 6.12 Time Based Pulse Input
Enables a choice between one of the 4 ramps
available, according to Table 6.7.
Same as Ramp bit 0.
1
0
0
1
1
A latched precise start only requires a pulse
of 3 ms on T18 or T19.
When using for 1–83 [1] or [2]:
When the reference is reached, the
frequency converter internally enables the
precise stop signal. The frequency converter
does the precise stop when the counter
value of 1-84 Precise Stop Counter Value is
reached.
Sends a latched stop signal when the
precise stop function is activated in
1-83 Precise Stop Function. The latched
precise stop inverse function is available for
terminals 18 or 19.
This function makes it possible to give an
external fault to the drive. This fault is
treated in the same way as an internally
generated alarm.
INCREASE signal to the digital potenti-
ometer function described in parameter
group 3-9* Digital Pot.Meter
DECREASE signal to the digital potenti-
ometer function described in parameter
group 3-9* Digital Pot.Meter
6 6
0
0
1
0
1
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