Rockwell Automation 836T Pressure Controls - Manuel (Page 2)

ATTENTION: The adjustment screw "A" should not be
forced beyond the range of the control indicated on the calibrated
scale. The adjustment screw "B" should not be adjusted beyond
the maximum specified differential of the control.
ATTENTION: All pistons are provided with a 1/8 inch
threaded drainopening which should be connected to an oil
r e t u r n l i n e l e a d i n g t o a n o i l r e s e r v o i r w h i c h i s v e n t e d t o
atmosphere. This reservoir may be at ahigher level of elevation
than the control. The controls with seal ringsusually do not
r e q u i r e r e t u r n l i n e s . H o w e v e r , t h e 1 / 8 i n c h t h r e a d e d
drainopening should never be plugged on either type of piston
control. Thisalso includes the shipping plug which must be
removed upon installa-tion. Filters should be used to reduce
contamination of hydraulic fluid.
OPERATION - A toggle mechanism operates the snap action switch at
a predetermined pressure setting. For the 2 - Circuit snap switch the
pressure causes the normally closed circuit 1-2 to open and normally open
circuit 3-4 to close. This is known as the trip pressure. When the pressure
returns to a lower predetermined setting, the circuit 1-2 will close and
circuit 3-4 will open. This is known as the reset pressure. The difference
between "trip" and "reset" pressure is the differential.
Similarly, for the 4 - Circuit snap switch, both normally closed circuits,
1-2 & 5-6 would open and both normally open circuits, 3-4 & 7-8 would
close on increasing pressure. On decreasing pressure, the contacts
would return to their original state at a predetermined setting.
Catalog number 836T-T251J can also be operated in a vacuum. At
a higher vacuum setting (lower pressure toward 30" Hg) the 2 - Circuit
switch contacts 1-2 will be closed and 3-4 open. At a lower vacuum
(higher pressure toward 0 psi) circuit 1-2 will open and circuit 3-4 will close.
EXAMPLE: Control set to close contacts at 15" Hg vacuum, open at
5" Hg vacuum. For the 2 - Circuit switch, circuit 1-2 would be used. For
the 4 - Circuit switch, circuits 1-2 or 5-6 would be used.
ADJUSTMENT - Generally, unless otherwise specified, controls shipped
from the factory are set at the maximum operating range pressure and
minimum differential.
The following procedure should be used to set the control to a
particular requirement.
OPERATING RANGE ADJUSTMENT: Turn lock nut on adjustment
screw "A" counterclockwise to loosen. Turn range adjustment screw "A"
clockwise to raise upper and lower pressure settings. To decrease the
upper and lower settings, turn screw "A" counterclockwise. The approxi-
mate upper pressure setting is shown by an indicator in the left window
between the calibration scales on the nameplate. When the proper setting
is reached, tighten the lock nut on screw "A" clockwise.
DIFFERENTIAL ADJUSTMENT: When the differential screw "B" is up
against the underside of the differential access opening in the cover the
control will function at minimum differential. To increase the differential,
turn adjustment screw "B" clockwise. This will decrease the lower setting
only. The higher setting will not change. Similarly, to decrease the differential
turn the differential adjustment screw "B" counterclockwise. This will raise
the lower setting only.
Condensed instructions can be found on the inside of the front cover.
NOTE: The use of a pressure gauge is desirable when setting the
control.
3 1
4 2 8 6
5 7
4 2
1 3
9
B
A
A
A or B circuits must be the same polarity.
2 - Circuit
Switch
4 - Circuit
Switch
Circuit 1-2 Opens
and 3-4 Closes
Circuits 1-2 & 5-6 Open
and 3-4 & 7-8 Close
CONTACT BLOCK WIRING SYMBOL
(Increasing Pressure Operation)
Isolated
Terminal
Operating variables in a system may cause changing pressure require-
ments. It is recommended that a periodic inspection of the gauge pressure
be made and the pressure control adjusted to compensate when necessary
for these changes.
PISTON TYPE APPLICATIONS -
PILOT LIGHT OPTION - A high intensity neon glow pilot light is available for
120 volt, 60 hertz applications and can be installed at the factory or in the
field. To order pilot light kit specify catalog number of existing control and add
N9 to this number. Optional pilot lights are available on special orders.
The pilot light is wired to the contact block as follows:
A. 2 - Circuit
Always connect lamp wires to same set of terminals used for the
load. To light on increasing pressure connect across
1-2. To light on decreasing pressure connect across 3-4.
B. 4 - Circuit
Consists of 2 electrically isolated single pole-double throw
circuits. Connect lamp wires to same set of terminals used for
load. To light on increasing pressure connect across 1-2 or 5-6.
To light on decreasing pressure connect across 3-4 or 7-8.
(or)
An isolated terminal, 9, is provided as a termination point when
an optional power source is used. This provides a convenient
means for various circuit connections when separation of the
load and pilot light is required. Circuits must be the same polarity
for pilot light connections and switching of auxiliary equipment.
PAINTING - Standard controls are supplied with a removable paint mask on
the nameplate. Remove the mask on final installation.
CONTACT BLOCK REPLACEMENT - To order Bulletin 836T Contact Block
2 - Circuit (SPDT-DB) Replacement Kit specify Catalog Number 836T-N1.
For the 4 - Circuit (DPDT-DB) Contact Block Replacement Kit specify
Catalog Number 836T-N2.
REPAIRS - Due to the integral construction of the Bulletin 836T Pressure
Control, it is recommended it be returned to the factory for repairs (excluding
contact block replacement). The control will be adjusted for optimum
performance and tested to specifications.