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EP0115178A2
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EP
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Digital controller
Assignee: Toshiba Corp
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Filing: 1983-12-21
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Granted: —
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Expires: 2003-12-21
Abstract
Abstract @ A digital process controller has a multiplexer (201) which receives the process variable (PV), and a microprocessor (21) which determines the manipulated variable signal (MV) necessary to control the variable to bring it to a desired setpoint. Counter (241) receives a count according to the MV signal and its output is pulse width modulated (242) and delivered to a bar graph driver (25) which drives a bar graph electronic display (263) so as to indicate the MV value. If the microprocessor (21) should fail, the control may be exerted manually using push buttons (262) which has the effect of changing the count in the counter (241). During such manual control, the MV value continues to be displayed on the display (263).
Inventors
- 👤 Keisuke C/O Patent Division Takada
- 👤 Masamichi C/O Patent Division Mizutani
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 12:27
CPC Classifications
G; G05; G05B; G05B15/00; G05B15/02; G05B19/00; G05B19/02; G05B19/04
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
119 words
A digital controller comprising a microprocessor (21) for determining a manipulated variable by arithmetic operations in accordance with a predetermined algorith to cause a process variable signal (PV) received by the microprocessor to follow a setpoint variable, an output system (24) for delivering a signal in accordance with the manipulated variable (MV) for controlling the process, the output system including holding means (241) for the manipulated variable; and indicating means (26) for displaying the process variable (PV), the setpoint variable (SV) and the manipulated variable (MV). characterised in that the indicating means (26) is electronic and has a driver (25) which is arranged to receive the manipulated variable (MV) from the holding means (241) of the output system (24).
Claim 2
Dependent Claim
119 words
A digital controller comprising a microprocessor (21) for determining a manipulated variable by arithmetic operations in accordance with a predetermined algorith to cause a process variable signal (PV) received by the microprocessor to follow a setpoint variable, an output system (24) for delivering a signal in accordance with the manipulated variable (MV) for controlling the process, the output system including holding means (241) for the manipulated variable; and indicating means (26) for displaying the process variable (PV), the setpoint variable (SV) and the manipulated variable (MV). characterised in that the indicating means (26) is electronic and has a driver (25) which is arranged to receive the manipulated variable (MV) from the holding means (241) of the output system (24).
Claim 3
Dependent Claim
19 words
2 . A digital controller according to claim 1, in which the driver (26)has two registers (252a, 252b), means
Claim 4
Dependent Claim
35 words
(27) for entering in the respective registers values of the process variable (PV) and setpoint variable (SV), and a counter (254) for receiving'the manipulated variable (MV) from the holding means (241) of the output system
Claim 5
Dependent Claim
35 words
(27) for entering in the respective registers values of the process variable (PV) and setpoint variable (SV), and a counter (254) for receiving'the manipulated variable (MV) from the holding means (241) of the output system
Claim 6
Dependent Claim
1 words
(24).
Claim 7
Dependent Claim
1 words
(24).
Claim 8
Dependent Claim
94 words
3 . A digital controller according to claim 2, in which the output system further includes pulse modulation means (242) for converting the output of the holding means (241) into pulses having a parameter dependent on the value of the manipulated variable (MV) in the holding means (241), and a converter (243) for converting the pulses from the modulation means (242) into an analogue signal for controlling the process; the driver (26) having input means for receiving the pulses and causing the counter (254) to receive a count according to the manipulated variable (MV).
Claim 9
Dependent Claim
44 words
A digital controller according to claim 3, in which the modulation means (242) are arranged to convert the output of the holding means (241) into pulses of a given frequency, the duty factor of which corresponds to the output of the holding means (241).
Claim 10
Dependent Claim
33 words
A digital controller according to claim 3, in which the modulation means is a pulse frequency scaler (242a) which generates pulses at a frequency dependent on the output of the holding means (241).
Claim 11
Dependent Claim
37 words
A digital controller according to claim 4, in which the input means include a source of clock pulses (290, 291) and gating means (253) for applying the clock pulses to the counter under control of the pulses.
Claim 12
Dependent Claim
31 words
A digital controller according to any one of the preceding claims, in which the electronic indicating means (26) include bar graph display devices (263a-263c) under the control of the driver (25).
Claim 13
Dependent Claim
35 words
A digital controller according to any one of the preceding claims, in which the holding means is a counter (241) connected to the microprocessor (21) to receive a count corresponding to the determined manipulated variable.
Claim 14
Dependent Claim
43 words
A digital controller according to claim 8, in which there are means (261, 262) for manually varying the count of counter (241) of the output system (24), thereby enabling manual control of the process and simultaneous display of the manually controlled manipulated variable.
References Cited (Backward Citations)
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