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The LOCAL/REMOTE switch is located on the
power supply control panel and controls
the mode of operation by determining how the
drive remote start relay (Kl) is energized
and deenergized.
This relay works in con-
junction with the drive START switch to
control the power on and off sequences.
Figure 3-1.1 shows the LOCAL/REMOTE power
sequencing control circuits.
The oper-
ation of these circuits in both local and
remote modes is explained in the following
paragraphs.
local Contra'
When the drive is in local mode, the remote
start relay (Kl) energizes whenever +20
volts is available.
In this mode, the power
on sequence (see figure 3-1.2) begins when
~e
START switch is pressed to light the in-
~1cator
(providing all circuit breakers and
1nterl?ck~ ~r7
closed).
The power off seq-
uence 1S 1n1t1ated by pressing the START
switch to turn off the indicator.
Remote·Contro'
In the remote mode, the start of the power
on sequence is controlled by the Sequence
Power (KS) and Remote Start relays as well
as the START swi tch.
Here, even of the
S~ART
switch is pressed (to light the in-
d1cator), the sequence does not begin until
both relays are energized.
The Sequence
Power relay (KS) energizes when all circuit
breakers are closed.
With KS energized, the
Remote Start relay (Kl) energizes to start
the power on whenever the Pick signal goes
low (see figure 3-1.1).
Therefore, if the START switch is on and the
circui~
breakers are closed, the Pick signal
dete~nes
when the power on sequence begins.
In a system where the Pick lines are connect-
ed in a daisy chain, the drives power up
sequentially, starting with the first drive.
A sequential power up occurs because each
drive waits until its spindle is up to speed
(K2 energizes) before passing the pick signal
to the next drive in the chain.
83318200
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Only the drives in the remote mode with their
START switches on (lighted) are involved in
the power up.
Drives in local or with their
START switches off (not lighted) are not in-
volved in the power up.
A drive that is not
involved passes the Pick Signal to the next
drive without delay providing its circuit
breakers are open thus deenergizing KS.
The Pick signal originates either at the con-
troller or a plug connecting to the I/O panel
of the first drive in the daisy chain.
(the
plug keeps the Pick signal permanently low)
with the Pick signal low, the first drive
begins ite power up sequence whenever its
START switch is pressed )providing all
breakers and interlocks are closed).
When
the spindle of the first drive gets up to
speed and the Speed relay (K2) energizes, the
Pick signlas go to the next drive.
This
sequence is repeated until all drives in the
remore mode with their START switches on are
powered up.
Once the Remote Start relay (Kl) has been
energized, the Hold signal keeps it energized
even if the Pick signal goes
inactive~
(Hold
like Pick, may orginiate wither at the con-
troller or the first drive).
This allows
powering down drives in the chain without
affecting other drives.
POWER ON SEQUENCE
Power application to the unit is sequenced by
logic and by relays within the power supply.
Refer to Figures 3-2 through 3-4.
When the circuit breakers are closed, ac and
dc power is enabled.
As the +SV power comes
up, Power Up Blanking acts as a master clear
to the logic.
Controller issuance of anSSR
command will result in a Device in Standby
and Positioner Busy status response.
OPI is
available if Online mode is selected by the
switch on the maintenance panel.
With a pack installed and all interlocks
closed, the unit may be powered up.
(on units
with power sequence feature Kl must also be
energized) Pressing the START switch on the
control panel has the following effects:
3-4.1 •
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