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236:. With hysteresis, there is no deadband and so the output is always in one direction or another. Devices with hysteresis have memory, in that previous system states dictate future states. Examples of devices with hysteresis are single-mode thermostats and smoke alarms. Deadband is the range in a process where no changes to output are made. Hysteresis is the difference in a variable depending on the direction of travel.
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exhibit hysteresis. For example, the furnace in the basement of a house is adjusted automatically by the thermostat to be switched ON as soon as the temperature at the thermostat falls to 18 °C and the furnace is switched OFF by the thermostat as soon as the temperature at the thermostat reaches
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A thermostat which sets a single temperature and automatically controls both heating and cooling systems without a mode change exhibits a deadband range around the target temperature. The low end of the deadband is just above the temperature where the heating system turns on. The high end of the
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within certain predetermined limits, but there is a range of voltage in-between during which no changes are made, such as between 112 and 118 volts (the deadband is 6 volts), or between 215 to 225 volts (deadband is 10 volts).
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systems. If mechanical backlash eliminators are not available, the control can compensate for backlash by adding the deadband value to the position vector whenever direction is reversed.
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or signal processing system where the output is zero (the output is 'dead' - no action occurs). Deadband regions can be used in control systems such as
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generally also have backlash and hence a deadband, which must be taken into account when making position adjustments, especially with
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216:) exhibit deadband. There is no drive from the input to the output shaft in either direction while the teeth are not meshed.
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22 °C. There is no temperature at which the house is not being heated or allowed to cool (furnace on or off).
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Johnson, Curtis D. "Process
Control Instrumentation Technology", Prentice Hall (2002, 7th ed.)
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deadband is just below the temperature where the air-conditioning system starts.
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319:. Department of Chemical and Process Engineering, University of Strathclyde
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346:(2nd ed.). New Delhi: Prentice-Hall of India. pp. 15–16.
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283:"Dead Band Plus Hysteresis Estimation with ValveLink Diagnostics"
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systems). A form of deadband that occurs in mechanical systems,
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or repeated activation-deactivation cycles (called 'hunting' in
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104:Deadband is the period of dead-state of a system.
57:but its sources remain unclear because it lacks
292:. Fisher Controls International. October 2012
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167:Input and output of the deadband operator.
88:Learn how and when to remove this message
27:Band of input values yielding zero output
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7:
176:In some power substations there are
124:) is a band of input values in the
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343:Transducers & Instrumentation
206:is a mechanical form of deadband.
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317:Introduction to Process Control
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18:Neutral zone (control theory)
232:Deadband is different from
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228:Hysteresis versus Deadband
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43:This article includes a
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340:Murty, D.V.S. (2009).
311:Postlethwaite, Bruce.
210:Gear teeth with slop (
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195:Backlash (engineering)
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244:Simple (single mode)
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193:Further information:
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146:proportional control
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172:Voltage regulators
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45:list of references
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122:neutral zone
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78:January 2013
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64:Please help
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246:thermostats
240:Thermostats
154:gear trains
142:oscillation
140:to prevent
70:introducing
359:18 January
323:18 January
296:18 January
269:References
234:hysteresis
218:Leadscrews
178:regulators
118:dead zone
114:dead-band
372:Category
257:See also
213:backlash
204:Backlash
189:Backlash
158:backlash
152:such as
110:deadband
182:voltage
66:improve
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286:(PDF)
132:in a
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