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Process Indicators
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Process indicators are used for display and/or control of process variables in applications that use analog signals representing pressure, temperature, weight, etc.
DC Volt Meters will display in proportion to the voltage applied to the input. Several input ranges allow their use in a variety of applications. In the lowest range, DC volt meters can replace old analog meters and provide more resolution and accuracy. Through the use of a shunt (resistor), DC volt meters can also be used to display motor load currents. The middle ranges accommodate operator input devices or process control electronics. On the high range, these meters can readout power supply or DC motor voltages.
DC Current Meters are popular when noise interference can disrupt voltage levels and are common signals used to drive old analog meters. Reference outputs of 0 to 1 mA, 0 to 5 mA, and 0 to 10 mA which are proportional to motor speed are also available from some AC drives.
Process Volt Meters and Current Loop Indicators operate similar to DC voltage and current meters, but include more extensive span and zero adjustments. Some popular signal ranges include –10 to +10 VDC, 4 to 20 mA and 10 to 50 mA current loops. These sensors are popular in industrial environments when their signals must be reliably transmitted over large distances, or when the signal is needed by more than one device. The minimum and maximum signal levels require adjustments at both ends of the range in order to provide a meaningful display.
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