4-20 CHAPTER 4: ELECTRICS
ALPHA 552
c) Lathe clamp signal (PLC input A1)
This signal is for checking the mode of the lathe clamping device (open), and is mainly used for the
feeding of a part, which takes place each time the clamp opens.
For safety reasons, wire a normally open contact, coming from the signal of the lathe
clamp. A clamp open signal must be selected.
d) Lathe in automatic cycle (PLC input A2)
This signal indicates that the lathe is in automatic cycle.
e) Load command (PLC input A3)
Should the lathe be equipped with a sub-spindle or the lathe is of twin spindle type, should the part
require multiple feeds, this signal will be used as a load command from the lathe.
For safety reasons, and to prevent collisions between the part being transferred to the second spindle
and the newly loaded bar stock when there is a simultaneous loading, the lathe must control the loading
of a new bar.
f) Feeding pusher control (PLC input A4)
This signal orders the forward movement of the feeding pusher and the bar, independently of the mode of
the lathe clamp.
As long as this signal is present, the signal of the foot switch to open and close the
clamping device of the lathe must be locked. The lathe should not start up in automatic
cycle as long as the clamping device does not grip the bar.
4.2.3. Signals from the barfeeder to the lathe
a) R1 alarm relay
When the barfeed system is in normal operation, the R1 relay signal is energized. In the event of an
alarm or break in the emergency stop circuit, this relay is de-energized.
For safety reason, this signal should bring to a stop all of the axis movements of the lathe as well as the
rotation of the spindle.
When the barfeed system is in alarm mode, the feeding pusher control signal should also de-
energize.
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