Page 156 ST 700 SmartLine Pressure Transmitters User’s Manual Revision 13
12.8.3 Output Check Procedures
The Output Check comprises the following procedures:
• The loop test procedure checks for continuity and the condition of components in the output
current loop.
• The Trim DAC Current procedure calibrates the output of the Digital-to-Analog converter for
minimum (0%) and maximum (100%) values of 4mA and 20mA, respectively. This
procedure is used for transmitters operating online in analog mode to ensure proper operation
with associated circuit components (for example, wiring, power supply, control equipment).
Precision test equipment (an ammeter or a voltmeter in parallel with precision resistor) is
required for the Trim DAC Current procedure.
• The Apply Values procedure uses actual Process Variable (PV) input levels for calibrating
the range of a transmitter. To measure a liquid level for example, a sight-glass can be used to
determine the minimum (0%) and maximum (100%) level in a vessel. The PV is carefully
adjusted to stable minimum and maximum levels, and the LRV and URV are then set by
commands from the MC Toolkit.
The transmitter does not measure the given PV input or update the PV output while it
operates in the Output mode.
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