Figure 10-8. Typical Process Instrument Loop

DOE-HDBK-1092-98

24V

Transmitter

I = 4-20mA

Signal

RL = 250 ohms

ground

Sensor

1-5V

Recorder

INSTRUMENTATION LOOPS

Figure 10-8. Typical Process Instrument Loop.

10.9.2.2.1 HAZARDS

The use of materials for something other than their original design criteria has the potential for

providing an additional hazard, especially to personnel unfamiliar with the research apparatus.

Personnel may assume that the material is used as originally designed and can unknowingly expose

themselves to hazards unless special precautions are followed.

Some examples of items used in an unconventional manner are:

1. Copper pipe used as an electrical conductor

2. Insulated flexible copper pipe used as an electrical conductor

3. Specially designed high-voltage or high-current connectors

4. Specially designed high-voltage or high-current switches

5. Water column used as a high-voltage resistor

6. Standard coax cable used in special high-voltage pulsed circuits

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