Hardy HI 3010 Filler/Dispenser Controller - Manual (Page 115)

99 CHAPTER 7
Troubleshooting
B1 - Guidelines for Instabilities on Former
Operating Systems (Cont’d)
B1
GO TO
B
Electrical
Physical Grounding -
All common equipment share a common ground point.
Keep the ground cable length to earth ground as short as possible.
Install a new ground rod if the cable length is excessive
B1.1
Cable -
Cuts or breaks in the loadcell cable insulation allow moisture to wick into the cable
and loadpoints. This can setup stray capacitance charges and allow ground
currents to exist. This could create a highly intermittent situation.
Vessel, Fill and discharge piping -
Ground all to a common point to eliminate electrical differences in
potential and static build-up.
Loadcells -
Ground straps must be installed to provide a direct discharge path
to ground around the loadpoints.
Cable Routing -
Separate high voltage sources and cables from low voltage signal cables.
Stay a minimum of 14 inches from magnetic fields and SCR controls.
Avoid parallel high voltage and signal cable runs.
Cable Shielding -
Ground low voltage cable shields only at the controller end.
Grounding both cable ends will produce ground currents.
Verify, with an ohm meter, the shield is only grounded at the weight controller.
Disconnect the shield at the controller and check for an pen circuit between
ground and shield. Reconnect the shield to ground and confirm a proper ground
path from the Junction Box to the controller.
Verify the shield is not connected to ground at the Junction Box.
Loadcell cable shields only pass through the Junction Boxes and are not connected
to ground at any point.
Weight Controller - Common AC ground and Chassis grounds.
B1.2
B1.3
B1.4
B1.5
B1.6
B1.7