Technical Support Document 014 - 5/97
INSTALLING THE DROP TABLE ENCODER UNIT
The Encoder unit is installed behind the column, using
four screws to attach it to the main mounting plate.
It's measurement cable is then connected to the moving
table itself, so the computer can monitor the table's
position.
-
Note the plate that is attached to
the encoder module. The four holes in the module's
plate line up with four threaded holes in the main
mounting plate, just behind the column. Also note
that the encoder module's measurement cable end
has a loop terminal on it. The terminal attached
to the moving part of the table. A screw may be
placed in the terminal when the module was shipped.
This screw is for ease of installation only, and
will later be discarded. The drawing below, left
shows the parts of the encoder module:
-
Place the Encoder Module on the main
mounting plate as shown, above, at right. The measurement
cable end will feed through the 1/2" hole in
the main plate. The screw in the terminal will allow
the cable to be pulled from the other side of the
plate after the module is secured.
- Screw the Module into place using the four 10-32
x 1/4" phillips screws provided. Make sure that
there are no obstructions between the module and the
surface to which it is mounted. Tighten all four screws.
Attach the Encoder measurement cable to the movable
table. The measurement cable with the ring-terminal
end will now be attached to the frame of the drop table.
- Looking over the top of the table, between the bellows
and the column, locate the two screws that hold the
bellows to the moving frame that supports the table.
(Lock the table in position about 12 to 16 inches
below the main mounting plate for the best view.)
Note that sone Drop Tables use velcro to secure the
bellows: these machines should still have two holes
in the baseboard frame for installation of this plate.
Remove each of these screws and replace it with the
8-32 x 1/2" phillips-head screws provided. These
slightly longer screws will allow the plate shown
above to be secured at the two notches.
- Once the new screws are in place, install the Cable
Attachment Plate under the two screws, with the notches
pointing towards the table (away from the column).
Standing in front of the table, and looking over it,
the plate should be in the same orientation as shown
above. Fully seat the plate into it's notches, and
tighten the screws. Be sure that the bellows are still
firmly attached.
- Very carefully pull the measurement cable down from
the Encoder Module (through the hole in the main mounting
plate), using the screw inserted in the ring terminal
as a handle. Extend the cable far enough to position
the ring terminal at the hole in the Attachment plate.
Secure the ring terminal using the small 4-40 x 1/4
inch flat-head screw provided.
NOTE: The Measurement Cable of the Encoder
Module is very fragile. Be very careful not to kink
or bend the cable while working. If pliers are used
to hold the cable, cover the jaws with masking tape.
When gripping the cable, do not turn the pliers so as
to bend or kink the cable. A bent cable will cause inaccurate
operation of the autofocus system. Do not let the cable
"snap" back into the Encoder Module: it may
break, making the module unusable.
- Once the cable end is attached, examine the cable
itself, from the hole in the main plate down to where
it is attached to the table's frame. It should be
parallel to the tensor spring next to it. If it is
slightly askew, adjust the position of the ring terminal
to bring it straight. If it is very angled, check
that the Cable Attachment Plate is installed correctly.
- Check the operation of the encoder's cable by moving
the table up and down. The cable should travel smoothly
and remain taught at all times.
Attach top of bellows to underside of column mounting
plate. The bellows that covers the front of the
Drop Table column are designed to mask the reflective
tensator springs to prevent image interference. The
bellows has steel plates at both the top and bottom.
The bottom plate was secured underneath the Cable Attachment
plate when the Encoder module was installed. The top
Plate will now be secured to the underside of the column
mounting plate.
- Locate the two small holes in the top bellows plate
(shown below). Working with only one side to start,
place one of the 6-32 x 3/4" screws (10-32 on
some models) up through one of the holes, so that
it projects up through the hole, as shown. While holding
the screw in place, put a spacer over the projecting
part of the screw.
Note: This is not necessary on machines that use velcro
to secure the bellows.
- Insert the screw, while holding it in place, along
with the spacer, into the threaded hole in the underside
of the column mounting plate. When installed, the
spacer should separate the bellows top plate from
the column mounting plate. This allows clearance for
the heads of the column's mounting bolts. Repeat for
the second screw. It will be necessary to move the
bellows around a bit to get behind them for turning
these screws. When finished, be sure that the plate
is straight.
- Check that the bellows are lying in an orderly manner,
and that they move accordingly as the table is moved
up and down.
Hookup the electrical cable from the Encoder Module.
The electrical hookup is simple. The cable from the
newly-installed encoder module plugs into the small
(D-9) connector located on the rear of the Sentinel
Enlarger's Negative stage. This is the connector immediately
next to the connector for the keypad/expansion junction
box. See below:
- Plug in the connector and secure it using the two
small lock screws at either end.
Tell the Sentinel Autofocus computer that the Drop
Table is installed. This is done in the Sentinel's
Preferences menu as follows.
- From the regular operating screen, press the MENU
key. Then press [5] or use the Arrow Keys to get to
the "SENTINEL PREFERENCES MENU" item. Press
ENTER.
- In the Preferences Menu, press [9] or use the Arrow
Keys to get to the "SET SECURITY LOCK" item
and then press ENTER.
- The screen will read "SECURITY LOCK ON"
on the top line. Press any of the number keys once
so that it reads "SECURITY LOCK OFF." Press
ENTER. This will disable the security lock, and then
return operation to the normal operating screen.
- Once again, get into the Preferences Menu, as described
above. In the Preferences Menu, press [8] or use the
Arrow Keys to get to the "ENABLE DROP TABLE"
item. Press ENTER.
- The screen will read "DROP TABLE NOT ACTIVE"
on the top line. Press any number key once to change
it to "DROP TABLE ACTIVE." Press ENTER.
- The autofocus system is now capable of reading the
position of the drop table. Since the Drop Table Encoder
is matched to the other encoders in the Sentinel,
there is no further setup necessary for autofocus
operation.
- Since the Drop Table at it's uppermost position
is not quite at the same position as the standard
bench-top baseboard (if the enlarger is being converted
from a bench top model) the lens setups will need
to be reprogrammed.
- Operation of the Drop Table is fully integrated
into the daily usage of the machine, simply move the
table to the desired position. The computer will even
indicate which direction, and how far, the table should
be moved when a change in printsize requires it!
|
