National Instruments PCI-1428

Chapter 2 Installation

instructions. All covers and filler panels must be installed while operating

the device.

Do not operate the device in an explosive atmosphere or where flammable

gases or fumes may be present. Operate the device only at or below the

pollution degree stated in the specifications. Pollution consists of any

foreign matter—solid, liquid, or gas—that may reduce dielectric strength

or surface resistivity. Pollution degrees are listed below.

• Pollution Degree 1—No pollution or only dry, nonconductive

pollution occurs. The pollution has no effect.

• Pollution Degree 2—Normally only nonconductive pollution occurs.

Occasionally, nonconductive pollution becomes conductive because of

condensation.

• Pollution Degree 3—Conductive pollution or dry, nonconductive

pollution occurs. Nonconductive pollution becomes conductive

because of condensation.

Clean the device and accessories by brushing off light dust with a soft,

nonmetallic brush. Remove other contaminants with a stiff, nonmetallic

brush. The unit must be completely dry and free from contaminants before

returning it to service.

You must insulate signal connections for the maximum voltage for which

the device is rated. Do not exceed the maximum ratings for the device.

Remove power from signal lines before connection to or disconnection

from the device.

Operate this device only at or below the installation category stated in the

specifications. Installation categories are listed below.

• Installation Category IV—for measurements performed at the source

of the low-voltage (<1000 V) installation. Examples include electricity

meters, measurements on primary overcurrent protection devices,

and ripple-control units.

• Installation Category III—for measurements performed in the building

installation. Examples include measurements on distribution boards,

circuit-breakers, wiring (including cables), bus bars, junction boxes,

switches, socket outlets in the fixed installation, equipment for

industrial use, and some other types of equipment, such as stationary

motors permanently connected to the fixed installation.

• Installation Category II—for measurements performed on circuits

directly connected to the low-voltage installation. Examples include