Installation Instructions
Original Instructions
Gravity Return Limit Switch with Indicating Light
Bulletin Number 802G
Product Overview
IMPORTANT
Save these instructions for future use.
A gravity return limit switch is a device that provides a low operating torque. It is
intended to be used in such a way that, once it has been operated, gravity acts on
the actuating lever to return the switch to the unopened state. When the lever is
rotated in either direction continuously, the device provides 180° of switch-on time
and 180° of switch-off time.
The operating head and the switch unit that are used in this style of device are
unique and can only be used with one another. Operating heads or switches from
other styles of devices cannot be interchanged with these devices.
IMPORTANT
This device is a gravity return limit switch, which must
be correctly configured to provide proper operation.
Once the switch is operated, gravity acts on the lever
arm, which supplies the return torque to rotate the
operating shaft back to the operating state. There is no
internal return mechanism. Carefully adjust the lever
arm length and position so that the unit has adequate
return force, but be sure that the returning lever arm
does not oscillate and operate the switch
unintentionally.
If unintentional switch operation creates a hazard, the
free-swinging mode of operation of the lever arm must
be avoided. You must provide a means to help prevent
lever arm oscillation, such as an external stop. Be sure
that this stop effectively damps any bounce of the
lever arm, which might also cause unintentional switch
operation.
Indicating Light
These instructions cover the style of limit switch that contains an indicating light.
This light can be wired to provide a visual indication of switch contact action.
The switch is available with either a 120V AC lamp circuit or a 240V AC lamp circuit.
The rated voltage for each device is displayed on the switch cover inside the
enclosure.
The lamp in this device cannot be replaced separately. If lamp replacement is
necessary, a new switch module and lamp assembly must be ordered as a renewal
part.
IMPORTANT
If used with solid-state or other sensitive devices,
leakage current (0.005 A) can cause false operation.
Mounting
Position the conduit that leads into the switch so that any fluid inside the conduit
does not drain into the switch enclosure. Apply the sealing compound to conduit
threads to help prevent against the entrance of fluids through the threads.
You can mount the base by either of two methods:
1.
Two #10…32 tapped holes are provided for rear mounting.
IMPORTANT
2.
Be sure the screws that are used for rear mounting are
not so long as to interfere with the screws that are
used to secure the front to the base.
Two clearance holes for #10 screws are provided for front mounting.
Wiring
IMPORTANT
The contacts in each switch element must have the
same polarity. The circuit diagram is shown on the
nameplate.
The pressure type connector terminals in the base accept 4 mm2 (12 AWG) and
smaller solid or stranded wire. For proper tightening, use nothing smaller than
1 mm2 (18 AWG). Before inserting the wire under the pressure plates, strip the
insulation approximately 9.5 mm (0.375 in). Tighten all pressure plate terminal
screws, whether used or not, to avoid interference with the screw cover.
A grounding screw is enclosed in the terminal base near the conduit opening. The
grounding screw has a self-lifting pressure plate and wire barrier. The proper
installation position of the ground wire is between the pressure plate and the wire
barrier in a direction parallel to the edge of the casting. Be sure that the ground
wire does not interfere with the gasket or the switch portion of the device.
You must wire the indicating light to a power source. You must provide lead wires
to connect to terminals 5 and 6 in the terminal block. The other ends of these leads
are connected to the points in the circuit that provide the desired indicating
function.
If the indicating light is to be connected internally across the limit switch
terminals, always connect the indicating lamp lead wires to the same set of
terminals used for the load. When connected across the normally open terminals 1
and 2, the light is on when the limit switch is in its unoperated state. When
connected across the normally closed terminals 3 and 4, the light is off when the
limit switch is in its unoperated state. See Figure 1 on page 3 for typical circuit
configurations.
Gravity Return Limit Switch with Indicating Light Installation Instructions
After completing the wiring, check that all wires are in the wiring cavity of the
terminal block so they do not interfere with the switch when it is plugged into the
terminal block. Recheck all terminal wiring screws for tightness.
For switched that have been wired at the factory, check the wire
color and their position in the terminal block for proper circuit
hookup.
When the switch has been plugged into the terminal block, securely tighten the two
cover screws to compress the body gasket.
Actuator Head Positioning
As shown in Figure 2 on page 3, you can place the actuator head in any of four
positions on the switch body:
1.
2.
3.
Loosen the four captive head screws.
Place the head in the desired position.
Securely retighten the four screws.
Lever Arm Positioning
Screwdriver slots are provided on each end of the operating shaft, which can be
used to keep the shaft from rotating while adjusting the position of the lever arm:
1.
2.
Loosen the screw that secures the lever arm clamping assembly to the
operating shaft.
Position the shaft so that in the unoperated state the circuit between
terminals 1 and 2 is open and between terminals 3 and 4 is closed.
The switch does not function as a gravity return device if the shaft is positioned
with the circuit functions reversed. The circuit functions are reversed if in the
unoperated state the circuit between terminals 1 and 2 is closed and between 3
and 4 is open.
Select the switch operating point so that the weight of the lever arm returns the
unit to the unoperated state. Be sure that the maximum travel position of the lever
is below the level that will cause the lever arm to oscillate in a pendulum manner,
operating the switch unintentionally after gravity returns it to its unoperated
position. After installing or adjusting the device, always check for this swinging
action before energizing the circuit.
See Product Overview on page 1 for restrictions on the freeswinging mode of operation
Lever Arm Rod Length Adjustment
The effective lever arm length can be varied by loosening the screw that secures
the rod in the clamping block.
As the rod length that extends below the clamp assembly is
shortened, the operating torque and return torque decrease, while
the allowable angular overtravel increases.
2
Rockwell Automation Publication 802G-IN002A-EN-P - May 2021
Gravity Return Limit Switch with Indicating Light Installation Instructions
Figure 1 - Typical Indicating Light Circuits
Numbers correspond to terminal block markings.
1
2
5
6
3
4
5
6
1
2
Load
Internal connection to N.O. contact.
Light on when the switch is unoperated.
Load
Internal connection to N.C. contact.
Light off when the switch is unoperated.
Will not light if an external series contact is open.
Load
5
6
1
2
Light on when either contact is open.
Load
5
6
1
2
Indicate load energized; similar connection can be made with N.C. contact.
Load
6
5
1
2
Alternate connections to isolate the light from the load circuit if leakage current through
the load is undesirable.
Load
3
4
5
6
Light is on when switch is unoperated. Similar connection can be made with load and light
connections reversed.
Figure 2 - Actuator Head Position
Rockwell Automation Publication 802G-IN002A-EN-P - May 2021
3
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Publication 802G-IN002A-EN-P - May 2021 | Supersedes Publication XXXX-X.X.X- December 1978
Copyright © 2021 Rockwell Automation, Inc. All rights reserved. Printed in the U.S.A.
40060-198-01
40060-198-01 Ver 02
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