Kodak 1200I manual E. Common Mistakes by Technicians/Customers, a Secondary Grounding

KODAK 1200i WIDE-FORMAT PRINTING SYSTEM

E. Common Mistakes by Technicians/Customers

1.The printer should only be grounded to the buildings electrical receptacle/outlet using the power cable provided and should conform to all electrical building grounding regulations in accordance with country/regional regulations. If a printer grounding problem is discovered only have a certified electrician ground the power source receptacle properly.

CAUTION: Do not implement any of the following actions listed below or personnel hazards and/or equipment damage may result:

a) Secondary Grounding

-If the receptacle or power strip is grounded (or thought to be grounded) do not attach a secondary ground to printer under any circumstances. This can be dangerous to the operator and/or equipment. Introduction of a ‘ground loop’ into the equipment can cause different problems/symptoms to suddenly appear and can be dangerous to the operator.

What is ground loop?

A ground loop occurs when there is more than one ground connection path

between two pieces of equipment. The duplicate ground paths form the equivalent of a loop antenna which very efficiently picks up interference currents. Lead resistance transforms these currents into voltage fluctuations. As a consequence of ground-loop induced voltages, the ground reference in the system is no longer a stable potential, so signals ride on the noise. The noise becomes part of the program signal.

Ground loop is a common wiring condition where a ground current may take more than one path to return to the grounding electrode at the service panel. AC powered computers all connected to each other through the ground wire in common building wiring. Computers may also be connected by data communications cables. Computers are therefore frequently connected to each other through more than one path. When a multi-path connection between computer circuits exists, the resulting arrangement is known as a "ground loop". Whenever a ground loop exists, there is a potential for damage from intersystem ground noise. The ground loop theory also applies for printers connected to these same computers, but the primary difference is computers do not pull anywhere near the wattage demands of a Kodak 1200i printer.

While lower currents may cause a slight audible hum on signal lines (typically in video/audio electronics), higher currents can cause more serious problems such as sparking in connections (Ethernet port), damage to circuit assemblies signal wiring. Only perform printer installations using the recommended guidelines and ensure a proper printer ground is present.

Technical Training Guide 72