Walker Magnetics SMART-D SERIES - Manual (Page 21)

O.S. WALKER Co., Inc. SMART-D Control
SMART D MANUAL DD14511L Rev. L, March 30, 2011
4-7
4.8 Grounding & Shielding
The optional chuck control outputs for current sense and part released are isolated from the
control circuit ground. All other chuck control electrical inputs and outputs, if connected to
electronic equipment, must be isolated from the control's internal circuit ground, which is
connected to the AC safety ground (the green or green/yellow wire in the AC line cord). The
base of the chuck is to be grounded to this point, as well as, through the ground wire of the
DC chuck cable. All electrical chassis must be safety grounded.
The chuck control's DC power output leads MUST BE SEPARATELY ROUTED from other
115V level power leads in the machine. They must not be routed in the same wire bundle with
400V or other high voltage leads. If the control has LOW VOLTAGE signal leads wire through
the machine, these MUST BE SEPARATELY ROUTED in their own SHIELDED WIREWAY
and the shield grounded to the machine chassis. Low voltage signals must not be routed with
high voltage or high power cables through any part of the machine, or electromagnetic
interference may result.
4.8.1 Current Sensing
This control is equipped with a current sensing feature that monitors the current flowing
to the chuck and indicates when this current has reached a predetermined value. The
predetermined value is set by adjusting the variable potentiometer to the desired point
and then pressing the residual pushbutton while holding down the variable pushbutton.
When the preset value is reached, the Variable indicator light stays on and the current
sense relay closes. If the current flowing to the chuck goes below the preset value, the
variable light will flash. See section 3.1.8 for more information.
4.8.2 Part Release
When the control enters the Full and Variable modes Part Release relay energizes.
When the control comes to the end of a release cycle the Part Release relay de-
energizes. See section 3.1.9 for more information.
4.8.3 Lockout
A Lockout feature is supplied with this control which prevents anyone from accidentally
changing the settings while machining is in progress. When the lockout signal is low
(0V), the feature is disabled and when the signal is high (+5V), the feature is enabled.
The feature can be operated in two different manners. See section 3.1.10 for more
information.
4.9 Control Output Voltage
The DC voltage for the magnet is connected across terminals 1 and 2 on TB1. This voltage
may be measured across these terminals and can vary from 0-115VDC and 0-230VDC
depending on the model control and its settings.