Term
| List five functions of an electronic controller |
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Definition
Locations
Signal Isolation
Signal Conversion
Signal Comparison
Process Indication
Power Supply
Control Modes
Direct Manual Control |
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Term
| What are some advantages of digital controllers |
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Definition
Digital controllers have no potentiometers to adjust, so no calibration drift occurs
Digital display versus analog display is more user friendly
No idicator needles which can stick
D. Most digital controllers utilize contact outputs for external alarms to be generated with no additional instrumentation requirements.
on-line diagnostics
newer models have self tuning
modbus |
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Term
| What are some disadvantages of digital controllers |
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Definition
Digital to analog or analog to digital conversion causes step changes due to their conversion method that can result in cycling the final control element.
2.loss of indicating display can leave operators blind
3.digital controllers are more seceptible to radio frequency interference than analog controllers. |
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Term
| State how the primary and secondary loops interact in a casacade control loop |
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Definition
| The output of the master controller is the setpoint for the slave controller. The slave controller is responsible for actuating the FCE. |
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Term
| What are some of the advantages of cascade control? |
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Definition
Reduce process disturbance effects
More precise automatic adjustments
Uses standard instrumentation
Minimal cost |
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Term
| What are the steps to tuning a cascade control loop |
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Definition
1.Place Master Controller in Manual.
2.First, tune secondary loop (Slave
Controller) like a regular feedback control loop.
3.Next, tune primary loop (Master Controller) using secondary loop as final control element and tuning as a single control loop. |
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