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简单介绍：
- High Accuracy
- Direct % Carbon Readout
- Compatibility with all ZrO2 Carbon Probes
- Simple Installation and Operation
- Field Proven Equipment
- Easy Configurati
详情介绍：
UDC 6300 APPLICATION NOTE
Drum Level Pressure Compensation
PROBLEM
Steam pressure variations cause a varing Differential Pressure signal do to specific gravity changes between the variable head in the tank and the fixed reference leg outside the Tank. Provide a controller which provides continuous correction of the measured drum level to correct for these variations in steam pressure as the steam demand fluctuates .
SOLUTION
Specify a UDC 6300 with the math algorithm configured as a “summer-divider" to calculate the effect of variations in steam pressure on the DP measurement of the liquid interface level in the steam
drum. The error presented by the varing steam density is compensated by the math equation, so the PV used by the Level Contol PID algorithm is the corrected actual level , not the DP measured by the transmitter.
The level controller output is then trated identical to the output from a non- pressure compensated Drum level application. Typically this is used in a 3 - Element Strategy where the Steam Flow signalis uaed as a feed forward Summer on the level control output which is then sent t0o tthe Feed water controller (loop 1) as a internal cascade setpoint. This FIC modulates the flow of the feedwater to continuously maintain the correct drum level. This is illustrated below.
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