US3819950A - Reference voltage generator for thermal processes having an exponential temperature-time characteristic - Google Patents
Reference voltage generator for thermal processes having an exponential temperature-time characteristic Download PDFInfo
- Publication number
- US3819950A US3819950A US00361551A US36155173A US3819950A US 3819950 A US3819950 A US 3819950A US 00361551 A US00361551 A US 00361551A US 36155173 A US36155173 A US 36155173A US 3819950 A US3819950 A US 3819950A
- Authority
- US
- United States
- Prior art keywords
- regulator
- input
- capacitor
- exponential
- output
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/1902—Control of temperature characterised by the use of electric means characterised by the use of a variable reference value
- G05D23/1904—Control of temperature characterised by the use of electric means characterised by the use of a variable reference value variable in time
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D23/00—Control of temperature
- G05D23/19—Control of temperature characterised by the use of electric means
- G05D23/20—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature
- G05D23/22—Control of temperature characterised by the use of electric means with sensing elements having variation of electric or magnetic properties with change of temperature the sensing element being a thermocouple
Definitions
- the voltage increase across the capacitor during charge or the voltage decrease across the capacitor during a subsequent discharge is employed selectively as a reference voltage for controlling, respectively, a rising and a falling exponential temperature-time characteristic of the thermal process.
- a cathode follower or other input buffer amplifier is coupled to the output of the capacitor to isolate the R-C circuit from the loading effect of the input of the regulator.
- FIG. 1 is a curve showing a typical exponential temperature-time variation suitable for certain types of controlled furnaces.
- FIG. 2 is a block diagram of an arrangement in accordance with the invention for generating a reference control voltage proportional to the exponential temperature-time relationship of FIG. 1.
- FIG. 2 A closed-loop temperature regulation system of a type appropriate for instrumenting the temperaturetime characteristic of FIG. 1 is shown in FIG. 2.
- the quantity of heat to be applied to a furnace 7 to be regu lated is controlled by a conventional furnace regulator 6.
- the regulator is responsive to an error signal obtemperature characteristic of the furnace is to be linear (wherein the drive mechanism for the wiper arm can be instrumented in a straightforward way by a motor driven in accordance with velocity step function), the requirement of an exponential temperature variation requires, for the mechanically instrumented reference ,voltage generator, not only a motor but also mechanical motion-changing devices such as curved cams which are complicated and expensive.
- such second quantity ideally has an amplitude that decays exponentially, with a time constant corresponding to Ta.
- the first quantity mentioned above is the voltage output of a thermocouple or other thermoelectric element 8, which is disposed in thermal communication with the furnace 7.
- the second quantity is the voltage output of an exponential voltage generator 10.
- the desired reference control voltage for the furnace 6 may be obtained from the capacitor output by so selecting the values of the resistor 11 and the capacitor 12 that Theoretically, the capacitor output voltage could be applied directly to the input of the regulator as the desired reference voltage without intervening circuitry.
- a bufier amplifier 4 having a high input impedance (e.g. an impedance that preferably is at least 10 times as large as the'resistance of resistor 11) is coupled to the output of the circuit 3.
- Such amplifier 4 may typically be a cathode or an emitter follower.
- an adjustable voltage divider 5 of suitable reduction ratio may be provided as shown between the output of the amplifier 4 and the associated input of the regulator 6.
- con-v time is converted to a first proportional electrical signal which is compared continually at the input of a furnace regulator with a second electrical reference signal whose amplitude-time characteristic is proportional to the desired exponential characteristic of the process to generate an error signal employed by the regulator to control the quantity of heat supplied to the process, an improved arrangement for generating the referenced signal, which comprises:
- an electrical wave shaping path including a resistor and a capacitor in series, the values of the resistor and the capacitor being chosen so that the resulting time constant of the path is equal to Ta:
- the coupling means comprises a high input impedance buffer amplifier.
- the coupling means further comprises a voltage divider disposed between the output of the buffer amplifier and the input of the regulator.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Automation & Control Theory (AREA)
- Control Of Temperature (AREA)
- Feedback Control In General (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT433172A AT322239B (de) | 1972-05-18 | 1972-05-18 | Schaltung zur erzeugung einer zeitveränderlichen vergleichsspannung als gleitender sollwert in elektronischen temperaturreglern |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3819950A true US3819950A (en) | 1974-06-25 |
Family
ID=3562613
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US00361551A Expired - Lifetime US3819950A (en) | 1972-05-18 | 1973-05-18 | Reference voltage generator for thermal processes having an exponential temperature-time characteristic |
Country Status (6)
| Country | Link |
|---|---|
| US (1) | US3819950A (it) |
| AT (1) | AT322239B (it) |
| CH (1) | CH559391A5 (it) |
| DE (1) | DE2322694C3 (it) |
| FR (1) | FR2185291A5 (it) |
| IT (1) | IT985072B (it) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3153413C2 (en) * | 1981-03-06 | 1988-06-30 | Rene Muraz Ch Rossier | Method for controlling the supply and the extraction of energy in material phase |
| DE3108470A1 (de) * | 1981-03-06 | 1982-09-30 | Schweizerische Aluminium AG, 3965 Chippis | Verfahren zur steuerung der energie-zu- resp.-abfuehrung sowie verwendung des verfahrens |
| DE3139199A1 (de) * | 1981-10-02 | 1983-04-21 | Braun Ag, 6000 Frankfurt | Verfahren und anordnung zur steuerung und regelung der heizleistung eines elektrischen heiz- und/oder trockungsgeraetes |
-
1972
- 1972-05-18 AT AT433172A patent/AT322239B/de not_active IP Right Cessation
-
1973
- 1973-04-18 CH CH584273A patent/CH559391A5/xx not_active IP Right Cessation
- 1973-05-05 DE DE2322694A patent/DE2322694C3/de not_active Expired
- 1973-05-15 FR FR7317454A patent/FR2185291A5/fr not_active Expired
- 1973-05-16 IT IT50004/73A patent/IT985072B/it active
- 1973-05-18 US US00361551A patent/US3819950A/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE2322694B2 (de) | 1976-11-04 |
| CH559391A5 (it) | 1975-02-28 |
| AT322239B (de) | 1975-05-12 |
| IT985072B (it) | 1974-11-30 |
| DE2322694A1 (de) | 1973-11-29 |
| DE2322694C3 (de) | 1978-04-13 |
| FR2185291A5 (it) | 1973-12-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| USRE23121E (en) | Antihunting electrical measuring and control apparatus | |
| US4390874A (en) | Liquid crystal display system having improved temperature compensation | |
| US2426711A (en) | Antihunt electrical servomotor system | |
| US3819950A (en) | Reference voltage generator for thermal processes having an exponential temperature-time characteristic | |
| US2874906A (en) | Control apparatus with process analog | |
| US3239723A (en) | Alternating current voltage sensor | |
| US4549623A (en) | Apparatus for automatically monitoring a constant current source in a measuring instrument | |
| US3694720A (en) | Speed control for d.c. motor | |
| US2750547A (en) | Electrical measuring apparatus | |
| US2520462A (en) | Recalibrating motor control apparatus | |
| US2822978A (en) | Simplified alternating current rate circuit | |
| US4117307A (en) | Control system for charging and discharging an electric storage heater | |
| US2857562A (en) | Electrical damping network | |
| US3529180A (en) | Proportioning control circuit | |
| US3103573A (en) | Liter | |
| US2583339A (en) | Servomotor damping system | |
| US2929980A (en) | Transistorized acceleration time rate delay circuit for direct current motor speed controller | |
| US3692986A (en) | Process control method and apparatus for regulating temperature | |
| US3771038A (en) | Drift correcting servo | |
| US2560256A (en) | Recording voltmeter | |
| US2486935A (en) | Voltage controlled proportional positioning apparatus | |
| US2887271A (en) | Multiple point proportioning controller | |
| US2704822A (en) | Standardization of null-type measuring systems | |
| SU1120301A2 (ru) | Устройство дл регулировани температуры | |
| US2492007A (en) | Electronic system for energizing direct-current motors from an alternating-current source |