Maple Systems HMI5000P - Manual (Page 6)

6 HMI5000P Installation Guide
1010-1014 Rev 01 www.maplesystems.com
Connect the HMIs chassis ground terminal to a reliable earth ground
with a low-resistance path.
Route all earth ground wires that lead from the HMI, the PLC, the power
supply, and the line filter to a central earth ground point such as a barrier
strip. This will ensure that no ground current from one device influences
the operation of the other devices.
Connect the HMI chassis ground terminal to the control panel door using
a heavy-gauge short braided cable or ground wire to minimize resistance.
Connect the power cable’s shield wire to the HMI’s chassis ground terminal.
Connect the control panel to earth ground using a copper grounding rod
close to the HMI and control panel.
Hinged doors on control panels do not provide a long-term electrical
connection to the rest of the enclosure. Corrosion develops over time and
prevents good electrical contact. For this reason, a separate wire braid
should be installed from the hinged control panel to the rest of the
enclosure.
For a more in-depth overview of ground wiring techniques, refer to
Technical Note #1027, “OIT Ground Wiring and Electrical Noise
Reduction,” which you can find in the Tech Notes section on our web site.
Connect HMI Chassis Ground to Control Panel
To reduce the possibility of electrical interference, connect the chassis
ground terminal of the HMI to a clean earth ground. If the control panel
is metal, make sure it is properly grounded. Then connect a short heavy-
gauge wire (#14 AWG) from the chassis ground terminal of the HMI to a
mounting bolt on the control panel door. The mounting bolt must have
good electrical contact to the control panel; scrape away any paint that
may be covering the panel to provide a good connection.
NOTE: If the control panel is made of a non-conductive material, it is
essential that you connect the chassis ground terminal of the HMI to a
clean earth ground point located close to the panel.