Maple Systems HMI5043DL, Installation Manual

HMI5000L Installation Guide                                                                                                7

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Control Panel Grounding

The control panel must be connected to a good, high-integrity earth 
ground both for safety considerations and shielding purposes. Maple 
Systems cannot overemphasize the importance of good grounding. 
Failure to use good grounding procedures during installation may cause 
sporadic malfunction of the HMI.

Connect the HMI chassis ground terminal to a reliable earth ground with 
a low-resistance path. Refer to Figure 1:



  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 using a 

heavy-gauge short braided cable (#14 AWG) or ground wire to minimize 
resistance. Then, make sure the panel is properly grounded to a clean 
earth ground.

Note:

 If the control panel is made of a non-conductive material, it is 

essential that the chassis ground terminal of the HMI is connected to 
a clean earth ground point located close to the panel. 



  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”  
in the Technical Notes section of the Maple Systems website.

Installation

It is necessary to follow all installation procedures described in this 
chapter for electrical noise immunity and CE compliance. The Maple 
Systems HMI is designed to connect easily to a PLC. External rear 
connectors provide quick connections for power, communications and 
programming wiring.