Self contained data acquisition apparatus and system

• US 4,672,529 A
• Filed: 10/26/1984
• Issued: 06/09/1987
• Est. Priority Date: 10/26/1984
• Status: Expired due to Fees

• Current Assignee: Autech Partners Limited
• Original Assignee: Autech Partners Limited
• Inventors: Kupersmit, Carlos A.
• Primary Examiner(s): Smith, Jerry
• Assistant Examiner(s): MacDonald, Allen
• Application Number:
  US06/665,166
• Time in Patent Office: 956 Days
• Field of Search: 364/130, 364/184, 364/186, 364/187, 364/551, 324/51, 324/73 R, 324/73 AT
• US Class Current: 700/1
• CPC Class Codes: G05B 2219/31192 Token passing protocol, priority token passing
• CPC Class Codes: G05B 2219/31455 Monitor process status
• CPC Class Codes: G05B 23/0235 based on a comparison with predetermined threshold or range, e.g. "classical methods", carried out during normal operation; threshold adaptation or choice; when or how to compare with the threshold
• CPC Class Codes: G06F 11/0796 Safety measures, i.e. ensuring safe condition in the event of error, e.g. for controlling element
• CPC Class Codes: G06F 11/16 Error detection or correction of the data by redundancy in hardware
• CPC Class Codes: G06F 11/2038 with a single idle spare processing component

Abstract

A self contained data acquisition and control system and apparatus with direct process input and output capability. Designed to operate within the harsh environment of a process zone, the apparatus employs a variety of process monitoring and control modules which perform under the direction of redundant computer controllers. These controllers provide control data loading to the modules as well as receive and transmit process status data. The modules are each formed having a hardware control and status monitoring circuit which performs in conjunction with a module microprocessor based control. One module provides for field contact actuation in combination with a technique for deriving data signals form the contact and associated field wiring for evaluating the performance of those same field contacts. Another module provides an isolated electronic switch output wherein the battery power supply or the like is provided with the control apparatus and the status of the load, the power supply and the switch itself is ascertained, while a third analog output module uniquely combines two analog outputs in redundancy an further exhibits status monitoring including full loop status monitoring from the point of derivation of the analog output at a digital analog to converter to the return current from the load itself.

Claims

1. An improved monitoring and control system for use with an industrial system where a process is carried out within a production environmental zone with the utilization of switching monitors and actuators with energizable loads coupled by a multiplicity of field wires to a control station, comprising:

an environmentally secure housing positionable within said zone;

switching input process interface means substantially positioned within said housing, including switch interface means connectable by field wiring with said switching monitors for deriving data signals and for evaluating the performance of said switching monitors and associated said field wiring to derive switching input status signals representing said data signals and said performance, and further including switching input process control means for controlling said switch interface means with respect to each said select switching monitor and receiving said status signals; and

controller means positioned within said housing and including communications processor means in interactive data transfer communication with said switching input process control means, controller memory means, controller central processing means for evaluating said switching input status signals received by said communications processor means and deriving corresponding process data output signals and for selectively controlling said switching input process control means.

2. The monitoring and control system of claim 1 in which:

said switch interface means comprises;

terminal means connectable with first and second said field wires extending to a said switching monitor;

means for applying a predetermined potential of first polarity to said first field wire and predetermined potential of second polarity to said second field wire;

bias response means coupled with said two field wires and said switching monitor in the vicinity of said switching monitor and deriving said data signals as a first analog voltage signal corresponding with said first field wire and a second analog voltage signal corresponding with said second field wire;

comparator means responsive to said first and second analog voltage signals and to predetermined threshold signals for deriving said switching input status signals;

threshold means actuable for generating said predetermined threshold signals; and

said switching input process control means selectively actuates said threshold means.

3. The monitoring and control system of claim 2 in which said bias responsive means includes an impedance network providing a first select impedance in parallel electrical connection with said select switching monitor and a second select impedance in series with said select switching monitor and said first field wire.

4. The monitoring and control system of claim 2 in which:

said threshold means comprises a digital-to-analog converter actuable to derive a said threshold signal as an analog voltage in response to an applied predetermined digital signal input; and

said switching input process control means selectively applies said predetermined digital signal input.

5. The monitoring and control system of claim 2 in which:

said switching input process control means selectively actuates said threshold means to derive a fault categorized said switching input status signal from said comparator means representing the presence of any detectable fault condition of said switching monitor and first and second field wires, and subsequently actuates said threshold means in the presence of a fault categorized one of said switching input status signals to provide a predetermined sequence of said threshold signals to derive evaluation characterized said switching input status signals from said comparator means.

6. The monitoring and control system of claim 2 in which:

said bias response means includes an impedance network providing a first select impedance in parallel electrical connection with said select switching monitor and a second select impedance in series with said select switching monitor and said first field wire;

said threshold means comprises a digital-to-analog converter deriving a said threshold signal as an analog voltage in response to actuation by an applied predetermined digital signal input; and

said switching input process control means selectively applies said predetermined digital signal input.

7. The monitoring and control system of claim 6 in which said switching input process control means actuates said threshold means by application of a predetermined sequence of said digital signal inputs to said digital-to-analog converter, each such signal input representing a predetermined state of said switching monitor and associated said two field wires.

8. The monitoring and control system of claim 1 further comprising:

switch output process interface means positioned within said housing and including;

terminal means connectable with a source of power and connectable by field wiring to said load;

a solid-state switch having a switching input connectable with said load and a switching output connectable with said source, said switch being actuable to conduct between said switching input and switching output in response to the assertion of a select bias signal;

first isolation means responsive to a command input signal for effecting the assertion of said select bias signal through dielectrically isolated signal transmission components to actuate said solid-state switch;

current detect network means connectable with said load and said source and having a load current output signal in the presence of a select value of detected load current;

second isolation means responsive to said load current output signal for providing, through dielectrically isolated transmission components, a load current status output;

switch output process control means for controlling said switch output process interface means by assertion of said command input signal and responsive to said load current status output to effect an evaluation with respect to said command input signal and provide switch output process status signals; and

said controller means communication processor means is in interactive data transfer communication with said switch output process control means.

9. The monitoring control system of claim 1 in which said controller means includes serial output processor means for interactive communication by serial data transmission along optical channels with a remote supervisory station.

10. An improved monitoring and control system for use with an industrial system wherein a process is carried out within a production environmental zone with energizable loads coupled by a multiplicity of field wires to a control station, comprising:

an environmentally secure housing positionable within said zone;

switch output process interface means positioned within said housing and including;

terminal means connectable with a source of power and connectable by field wiring to said load;

a solid-state switch having a switching input connectable with said load and a switching output connectable with said source, said switch being actuable to conduct between said switching input and switching output in response to the assertion of a select bias signal;

first isolation means responsive to a command input signal for effecting the assertion of said select bias signal through dielectrically isolated signal transmission components to actuate said solid-state switch;

current detect network means connectable with said load and said source and having a load current output signal in the presence of a select value of detected load current;

second isolation means responsive to said load current output signal for providing, through dielectrically isolated transmission components, a load current status output;

switch output process control means for controlling said switch output process interface means by assertion of said command input signal and responsive to evaluate said load current status output with respect to said command input signal and provide switch output process status signals; and

controller means positioned within said housing and including communications processor means in interactive data transfer communication with said switch output process control means;

first controller memory means, controller central processing means for evaluating said switch output process status signals received by said communications processor means and deriving corresponding process data output signals and for selectively controlling said switch output process control means.

11. The monitoring and control system of claim 10 in which said current detect network means comprises means for deriving a voltage drop in the presence of a predetermined level of current flow between said load and said source and voltage responsive means for deriving said load current output signal in response to said voltage drop.

12. The monitoring and control system of claim 10 including:

source status network means including current output means connectable with said source for deriving a predetermined source state current level in the presence of a select voltage level of said source, and third isolation means responsive to said source state current level for providing, through dielectrically spaced and isolated transmission components, a source status output; and

said switch output process control means is responsive to evaluate said source status output and said load current status output with respect to said command input signals and provide corresponding said switch output process status signals.

13. The monitoring and control system of claim 10 in which:

said solid-state switch exhibits a saturated condition when conducting under predetermined normal load conditions and a voltage drop condition under overload effects; and

including voltage monitoring network means connectable with said source of power and said switching input and responsive to said solid-state switch saturated and voltage drop conditions to exhibit corresponding switch monitoring conditions, and fourth isolation means responsive to said switch monitoring conditions for providing, through dielectrically isolated transmission components, an overload status output; and

said switch output process control means is responsive to evaluate said overload status output and said load curent status output with respect to said command input signals and provide corresponding said switch output process status signals.

14. The monitoring and control system of claim 13 in which:

said voltage monitoring network means comprises current limiting diode means coupled with said source, and a selective bias network exhibiting select impedance coupled between said current limiting diode means, said switching input and said source; and

said fourth isolation means includes a photo emissive diode coupled in current transfer relationship between said current limiting diode means and said selective bias network and a dielectrically isolated photoresponsive component for deriving an output responsive to the emissions of said photo-emissive diode for deriving said overload status output.

15. The monitoring and control system of claim 13 including:

source status network means including current output means connectable with said source for deriving a predetermined source state current level in the presence of a select voltage level of said source, and third isolation means responsive to said source state current level for providing, through dielectrically isolated transmission components, a source status output; and

said switch output process control means is responsive to evaluate said source status output, said overload status output and said load current status output with respect to said command input signals and provide corresponding said switch output process status signals.

16. The monitoring and control system of claim 15 in which said switch output process control means includes memory means for retaining a compilation of status words corresponding with select combinations of said source status outputs, said overload status outputs and said load current status outputs, and is responsive to received said status outputs to access said memory means to provide a corresponding said status word as said switch output process signal.

17. The monitoring and control system of claim 10 in which said controller means includes serial output processor means for interactive communication by serial data transmission along optical channels with a remote supervisory station.

18. An improved monitoring and control system for use with an industrial system wherein a process is carried out within a production environmental zone with the utilization of actuators with energizable loads coupled by a multiplicity of field wires to a control station, comprising:

an environmentally secure housing positionable within said zone;

terminal means connectable by said field wires with a said load;

first output drive interface means positioned with said housing and including;

first control input means responsive to a control signal input for deriving a corresponding analog signal of predetermined value,

first error stage means responsive to said analog signal and to a feedback signal to provide a control output corresponding with the difference of value and polarity thereof;

first current output means responsive to said control output for applying corresponding current from said terminal means to said load,

first ground stage means having an input coupled with said terminal means for receiving feedback current through a said field wire from said load and deriving said feedback signal as a voltage value in inverted correspondence with said feedback current, and

impedance means coupled with said first ground stage means input for deriving a voltage corresponding with said feedback current,

second output drive interface means positioned within said housing and including;

second control input means responsive to a control signal for deriving a corresponding analog signal of predetermined value,

second error stage means responsive to said analog signal and to a feedback signal to provide a control output corresponding with the difference of value and polarity between said feedback signal and said analog signal,

second current output means responsive to said control output for applying corresponding current from said terminal means to said load,

second ground stage means having an input coupled with said terminal means for receiving feedback current through a said field wire from said load and deriving said feedback signal as a voltage value in inverted correspondence with said feedback current, and

switch means coupled within said second ground stage input and actuable for effecting said feedback current receipt;

means for connecting said first ground stage input with said second ground stage input;

output drive process control means for controlling said first and second output drive interface means and for selectively actuating said switch means; and

controller means positioned within said housing and including communications processor means in interactive data transfer communication with said output drive process control means, controller memory means, controller central processing means for evaluating said status signals received by said communications processor means and deriving corresponding process data output signals and for selectively controlling said output drive process control means.

19. The monitoring and control system of claim 18 in which said first output drive interface means further includes override network means for clamping said first current output means to a predetermined constant current output in the absence of said receipt of said feedback current at said ground stage means.

20. The monitoring and control system of claim 18 in which said first ground stage means comprises amplifier stage means having an inverting configuration and effecting the establishment of virtual ground at its said input.

21. The monitoring and control system of claim 18 further comprising:

switch output process interface means positioned within said housing including;

second terminal means connectable with a source of power and connectable by field wiring to said load;

a solid-state switch having a switching input connectable with said load and a switching output connectable with said source, said switch being actuable to conduct between said switching input and switching output in response to the assertion of a select bias signal;

first isolation means responsive to a command input signal for effecting the assertion of said select bias signal through dielectrically isolated signal transmission components to actuate said solid-state switch;

current detect network means connectable with said load and said source and having a load current output signal in the presence of a select value of detected load current;

second isolation means responsive to said load current output signal for providing, through dielectrically isolated transmission components, a load current status output; and

switch output process control means for controlling said switch output process interface means by assertion of said command input signal and responsive to said load current status output to effect its evaluation with respect to said command input signal and provide switch output process status signal; and

said controller means communications processor means is in interactive data transfer communication with said switch output process control means.

22. An analog output circuit for connection with actuator derived loads, comprising:

output drive circuit means, including;

control input means responsive to a control signal input for deriving a corresponding analog signal of predetermined value;

error stage means responsive to said analog signal and to a feedback signal to provide a control output corresponding with the difference of value and polarity between said analog signal and said feedback signal;

current output means responsive to said control output for outputting current corresponding therewith at an output thereof to said load;

ground stage amplifier means configured to provide a virtual ground and having an input for receiving feedback current from said load and deriving said feedback signal as a voltage value in inverted correspondence with said feedback current;

output impedance means responsive to said current output means output for deriving a voltage out signal corresponding with said outputted current;

return impedance means responsive to said feedback current from said load for deriving a return signal as a voltage level corresponding with the value of said feedback current; and

comparison circuit means responsive to said voltage out signal and said return signal for deriving an effective voltage signal representing their difference and responsive to said control input means analog signal and said effective voltage signal for effecting a comparison of their values to derive a load status signal.

23. The analog output circuit of claim 22 in which said comparison circuit means is responsive to said analog signal and said ground stage amplifier means feedback signal for deriving a loop signal representing their difference and including dual threshold comparator means responsive to dual threshold reference inputs and said loop signal to derive a full loop status signal;

and

said comparison circuit means including first reference means for deriving said dual threshold reference inputs corresponding with a predetermined tolerance.

24. The analog output circuit of claim 23 in which:

said control output means comprises first and second analog-to-digital converters having respective inputs for jointly receiving a digital input representing a select drive to said load and having respective first and second said analog signals of opposed polarities at the outputs thereof;

said comparison circuit means includes means for summing said first and second analog signals to derive a converter check signal and is responsive to compare said converter check signal with said dual threshold reference inputs to derive a converter status signal.

25. The analog output circuit of claim 22 in which said comparison means includes second reference means for deriving a zero reference signal corresponding with a predetermined minimum current outputted by said current output means to represent a zero active current to said load, and said comparison means is responsive to compare said zero reference signal with said feedback signal to derive an input current status signal.

26. A switch output circuit for connection with loads, comprising:

switch output means including;

terminal means connectable with a source of power and connectable by field wiring to said load;

a solid-state switch having a switching input connectable with said load and a switching output connectable with said source, said switch being actuable to conduct between said switching input and switching output in response to the assertion of a select bias signal;

first isolation means responsive to a command input signal for effecting the assertion of said select bias signal through dielectrically isolated signal transmission components to actuate said solid state switch;

current detect network means connectable with said load and said source and having a load current output signal in the presence of a select value of detected load current;

second isolation means responsive to said load current output signal for providing a current status output; and

switch output process control means for controlling said switch output process interface means by assertion of said command input signal and responsive to said load current status output to effect an evaluation of said load current status output with respect to said command input signal.

27. The switch output circuit of claim 26 in which said current detect network means comprises means for deriving a voltage drop in the presence of a predetermined level of current flow between said load and said source, and voltage responsive means for deriving said load current output signal in response to said voltage drop.

28. The switch output circuit of claim 27 including:

source status network means including current output means connectable with said source for deriving a predetermined source state current level in the presence of a select voltage level of said source, and third isolation means responsive to said source state current level for providing, through dielectrically spaced and isolated transmission components, a source status output; and

said switch output process control means is responsive to evaluate said source status output and said load current status output to with respect to said command input signals and provide corresponding said swith output process status signals.

29. The switch output circuit of claim 26 in which:

said solid-state switch exhibits a saturated condition when conducting under predetermined normal load conditions and a voltage drop condition under overload effects; and

including voltage monitoring network means connectable with said source of power and said switching input and responsive to said solid-state switch saturated and voltage drop conditions to exhibit corresponding switch monitoring conditions, and fourth isolation means responsive to said switch monitoring conditions for providing, through dielectrically isolated transmission components, and overload status output; and

said switch output process control means is responsive to evaluate said overload status output and said load current status output with respect to said command input signals and provide corresponding said switch output process status signals.

30. The switch output circuit of claim 29 in which:

said voltage monitoring network means comprises current limiting diode means coupled with said source and a selective bias network exhibiting select impedance coupled between said current limiting diode means, said switching input and said source; and

said fourth isolation means includes a photo emissive diode coupled in current transfer relationship between said current limiting diode means and said selective bias network and a dielectrically isolated photoresponsive component for deriving an output responsive to the emissions of said photo-emissive diode for deriving said overload status output.

31. The switch output circuit of claim 29 including:

source status network means including current output means connectable with said source for deriving a predetermined source state current level in the presence of a select voltage level of said source, and third isolation means responsive to said source state current level for providing, through dielectrically isolated transmission components, a source status output; and

said switch output process control means is responsive to evaluate said source status output, said overload status output and said load current status output with respect to said command input signals and provide corresponding said switch output process status signals.

32. The switch output circuit of claim 31 in which said switch output process control means includes memory means for retaining a compilation of status words corresponding with select combinations of said source status outputs, said overload status outputs and said load current status outputs, and is responsive to received said status outputs to access said memory means to provide a corresponding said status word as said switch output process signal.

33. A system for monitoring the status of field contacts and the field wires which are operationally associated therewith, comprising:

contact monitoring means including;

terminal means connectable with first and second said field wires extending to said field contacts;

means for applying a predetermined potential of first polarity to said first field wire and a predetermined potential of second polarity to said second field wire;

bias response means coupled with said two field wires and said contacts in the vicinity of said contacts and deriving a first analog voltage signal corresponding with said first field wire and a second analog voltage signal corresponding with said second field wire;

comparator means responsive to said first and second analog signals and to predetermined threshold signals for deriving contact input status signals;

threshold means actuable for generating said predetermined threshold signals; and

contact input process control means for selectively actuating said threshold means and receiving said contact input status signals.

34. The system of claim 33 in which said bias response means includes an impedance network providing a first select impedance in parallel electrical connection with said field contacts and a second select impedance in series therewith and said first field wire.

35. The system of claim 34 in which:

said threshold means comprises a digital-to-analog converter actuable to derive a said threshold signal as an analog voltage in response to an applied predetermined digital signal input; and

said contact input process control means selectively applies said predetermined digital signal input.

36. The system of claim 34 in which said contact input process control means selectively actuates said threshold means to derive a fault categorized one of said input status signals from said comparator means representing the presence of any detectable fault condition of said field contacts and first and second field wires and subsequently actuates said threshold means in the presence of a said fault categorized input status signal to provide a predetermined sequence of said threshold signals to derive an evaluation characterized said contact input status signal from said comparator means.

37. The system of claim 34 in which:

said bias response means includes an impedance network providing a first select impedance in parallel electrical connection with said select switching monitor and a second select impedance in series with said select switching monitor and said first field wire;

said threshold means comprises a digital-to-analog converter deriving a said threshold signal as an analog voltage in response to actuation by an applied predetermined digital signal input; and

said contact input process control means selectively applies said predetermined digital signal input.

38. The system of claim 37 in which said contact input process control means actuates said threshold means by application of a predetermined sequence of said digital signal inputs to said digital-to-analog converter, each such signal input representing a predetermined state of said field contacts and associated said two field wires.