GERC_RLY Rev 2 Wiring and Usage manual
January 9, 2007
5
Should the switch fail, the GERC_RLY will not allow the motors to turn. Should the wires
leading to the switch be cut (by hot swarf, for example), the GERC_RLY will not allow the
motors to turn.
The GERC_RLY is shipped with a wire jumpering the EStop input, for testing purposes only.
As a minimum, an external switch
really
should be connected. It is strongly recommended that
EStop limit switches also be wired into the EStop loop, as shown below in Figure 2.
It is not enough to rely on limit switches wired to the controller. Should the Geckos fail
such that the motors run full speed, limit switches wired to the controller will be
ineffective.
The EStop switch carries relay power, and as such, the contacts cannot be shared with any
other device.
If an EStop switch is to be used to turn off the lathe or mill motor, for example, as well
as turning off the Geckos, then the EStop switch must be a multi pole device.
EStop Override
When limit switches are wired into the EStop circuitry (as recommended above), the
table/knee/quill will have to be moved to a position such that the limit switch is no longer open.
On a machine with handwheels, this presents no problem. On fully automatic machines, that
is, machines with no handwheels, a Catch-22 situation arises whereby the table can only be
moved by the Geckos and the GERC_RLY will not allow the Geckos to operate until the table
has moved.
X limit switch
Y limit switch
Z limit switch
Figure 2
J4
EStop switch
Figure 3
GERC EStop
J4
Other EStop device
