APPENDIX B: ELECTRICAL AND DATA CONNECTIONS
CD-A DUAL PULSE RESISTANCE WELDING POWER SUPPLY
B-6
990-430
Foot Switch Connector
(signals also present on the 37-pin I/O Connector)
Foot Switch Input
Function
Foot Switch Connector 37-pin I/O Connector
Chassis Ground
Pin # 1
---
Foot_1
Pin # 2
Pin # 5
Foot_2
Pin # 3
Pin # 23
Fire Common
Pin # 4
Pin # 24
The footswitch connector is located on the rear panel of the CD-A
Power Supply and can accommodate both single-level and two-level
footswitches or other 24VDC logic inputs. In order to correctly bias
the Foot Switch input for external 24VDC logic inputs, the
integrator can either set the Foot Switch input to either Sink (
LOW =
True Inputs
) or Source (
HIGH = True Inputs
). The Sink/Source
selection switch is located on the rear of the CD-A Power Supply
just above the Footswitch Connector. In general the bias switch is
only used when driving the Foot Switch input with an external
24VDC logic input. The switch position does not matter when using
a static footswitch.
Single-Level Footswitch
When implementing a single-level footswitch, connect the footswitch leads between the
Foot_2
and
Fire
Common
inputs. In addition, terminate the
Foot_1
signal by connecting it to
Fire Common
. When the
footswitch is depressed, the weld head moves into position and applies force to the weld pieces. After the
Squeeze delay, the Weld Current will flow and the Power Supply will automatically return the upper
electrode to its UP position when the weld schedule is complete.
Two-Level Footswitch
When using a two-level footswitch, connect position 1 (1
st
position) between
Foot_1
and
Fire Common
and position 2 (2
nd
position) between
Foot_2
and
Fire Common
. When the footswitch is depressed, the
Power Supply energizes the air actuated weld head. This causes the upper electrode to descend and apply
force to the weld pieces. If you release the foot switch before pressing it to the second level, the Power
Supply will automatically return the upper electrode to its UP position so that you may re-position the
weld pieces. If you continue pressing the footswitch down to the second level, the force-firing switch in
the weld head will close. Weld current will flow and the Power Supply will automatically return the upper
electrode to its UP position when the weld schedule is complete.
24VDC Logic Input
If connecting a PLC or other digital device to emulate the footswitch operation, select the appropriate
sink/source logic as defined above. Refer to
Appendix C, System Timing
for correct implementation of
the external Logic Source.
BIAS SWITCH
