Fisher 244EH, 244ER manual Operation, POWER SUPPLY Surges/Transients, Section, Safety Messages

Section

3 Operation

SAFETY MESSAGES

Warning

Safety Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 3-1 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 3-1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . page 3-2 Intermittent Sensor Algorithm . . . . . . . . . . . . . . . . . . . . . page 3-5

Instructions and procedures in this section may require special precautions to ensure the safety of the personnel performing the operations. Information that raises potential safety issues is indicated by a warning symbol (). Please refer to the following safety messages before performing an operation preceded by this symbol.

If the transmitter is installed in a measurement loop, disconnect power to the transmitter before beginning to set up the Model 244EC Configuration Interface. If the Model 244EC connects to a transmitter while the transmitter is powered in a measurement loop, the Model 244EC will shunt the electrical current, possibly resulting in a dangerous situation within the measurement loop.

POWER SUPPLY

Surges/Transients

The dc power supply should provide power with a ripple that is less than two percent of the nominal supply voltage. The total resistance load is the sum of the resistance of the signal leads and the lead resistance of any controller, indicator, or related piece of equipment in the loop. Note that the resistance of intrinsic safety barriers, if used, must be included.

The transmitter will withstand electrical transients of the energy level usually encountered in static discharges or induced switching transients. However, high-energy transients, such as those induced by lightning strikes, welding, heavy electrical equipment, or switch gears, can damage both the transmitter and the sensor.

To protect against high-energy transients, install Models 244E into a suitable connection head with the Rosemount Model 470 Transient Protector. The Model 470 prevents damage from transients induced by lightning, welding, heavy electrical equipment, or switching gears. Refer to the Model 470 Transient Protector Product Data Sheet (document number 00813-0100-4191) for more information.

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