Annunciator circuit for field point monitoring system

Claim 2

In a field point monitoring system including field point sensing means generating a first signal when a sensed variable is within preselected tolerance limits and a second signal when the sensed variable is outside such tolerance limits, the combination comprising first control means connected with the field point sensing means and having a normal state and an actuated state, said first control means assuming and thereafter remaining in said actuated state in response to the generation of the first signal by the field point sensing means, indicator control means selectively actuable to one of first and second operative states, second control means connected with said first control means, said indicator control means and the field point sensing means and having a normal state and an actuated state, said second control means assuming said normal state in response to the generation of the first signal by the field point sensing means and being responsive to said indicator control means to switch between said normal and actuated states whenever the second signal is generated by the field point sensing means, third control means connected with said first control means and said second control means and having a normal state and an actuated state, said third control means assuming said actuated state in response to actuation of said first and second control means, said indicator control means being connected with said third control means and assuming said second operative state in response to actuation of said third control means, and indicator means connected with said second control means for generating first and second perceptible indications when said second control means is in said normal and actuated states, respectively, whereby the status of the sensed variable may be readily monitored.

Claim 3

The invention as recited in claim 1 further including reset means connected with said indicator control means and said first control means for selectively placing said first control means in its normal state and said indicator control means in its first operative state.

Claim 4

The invention as recited in claim 2 wherein said indicator means comprises a visually perceptible indicator display, and further including an audible alarm connected with said indicator control means and generating an audibly perceptible signal when said indicator control means is in said second operative state.

Claim 5

The invention as recited in claim 3 wherein said indicator control means includes oscillator means connected with said second control means for alternately placing said second control means in said normal and actuated states when said indicator control means is in said second operative state.

Claim 6

The invention as recited in claim 1 wherein said first control means comprises a pressure operated relay having an outlet port communicating with said second and third control means, said pressure operated relay having a second port and being moved to an actuated position in response to a particular fluid pressure at said second port, and wherein a flow restrictor communicates with said second port and said outlet port to provide a feedback path for locking said pressure operated relay in its actuated position.

Claim 7

The invention as recited in claim 1 wHerein each of said first, second and third control means comprises a respective one of first, second and third pressure operated fluidic relays.

Claim 8

The invention as recited in claim 6 wherein each of said first, second and third pressure operated fluidic relays has an inlet port, an outlet port, a third port and a fourth port, each of said pressure operated fluidic relays moving to an actuated position in response to fluid pressure at said third port and being locked in a normal position in response to fluid pressure at said fourth port.

Claim 9

The invention as recited in claim 7 wherein said outlet port of said first pressure operated relay communicates with said inlet port of said second pressure operated relay and said third port of said third pressure operated relay.

Claim 10

The invention as recited in claim 8 wherein said outlet port of said second pressure operated relay communicates with said indicator means and said fourth port of said third pressure operated relay.

Claim 11

The invention as recited in claim 9 wherein said fourth port of said second pressure operated relay communicates with the field point sensing means, and wherein said outlet port of said third pressure operated relay communicates with said indicator control means.

Claim 12

A pneumatically operated control network including a first control means having first and second inputs and an output, said first control means assuming a first position in response to the presence of a signal at said first input, said first control means presenting a signal at said output when in said first position, said first control means remaining in said position upon subsequent removal of said signal at said first input, said control means assuming a second position in response to the presentment of a signal at said second input, said first control means remaining in said second position upon removal of a signal presented to said second input provided a signal is not present at said first input; a second control means having three inputs and an output, one of said three inputs being connected with said d output of said first control means, another of said three inputs being connected to said first input of said first control means, said second control means having a first position providing a connection between said one of said three inputs and said output of said second control means, said first position being provided so long as a signal is presented at said another of said three inputs, said second control means providing a second position to remove said connection between said one of said three inputs and said output of said second control means, said second position being provided when a signal is not presented at said another of said three inputs with a signal presented at the last of said three inputs; and a third control means having two inputs and an output, the first of said two inputs connected with said output of said second control means, the second of said two inputs connected with the output of said first control means, said third control means presenting a first position so long as a signal is presented at said first of said two inputs of said third control means, said third control means presenting a second position providing a signal at said output of said third control means, said second position being provided when a signal is not present at said first of said two inputs of said third control means with a signal presented at said second of said two inputs of said third control means, said output of said third control means providing a control signal output for the network.

Claim 13

A pneumatically operated control network including a first control means having first and second inputs and an output, said first control means assuming a first position in response to the presence of a signal at said first input, said first control means presenting a signal at said output when in said first position, said first control means remaining in said position upon subsequent removal of said signal at said first input, said control means assuming a second position in response to the presentment of a signal at said second input, said first control means remaining in said second position upon removal of a signal presented to said second input provided a signal is not present at said first input; a second control means having three inputs and an output, one of said three inputs being connected with said d output of said first control means, another of said three inputs being connected to said first input of said first control means, said second control means having a first position providing a connection between said one of said three inputs and said output of said second control means, said first position being provided so long as a signal is presented at said another of said three inputs, said second control means providing a second position to remove said connection between said one of said three inputs and said output of said second control means, said second position being provided when a signal is not presented at said another of said three inputs with a signal presented at the last of said three inputs; and a third control means having two inputs and an output, the first of said two inputs connected with said output of said second control means, the second of said two inputs connected with the output of said first control means, said third control means presenting a first position so long as a signal is presented at said first of said two inputs of said third control means, said third control means presenting a second position providing a signal at said output of said third control means, said second position being provided when a signal is not present at said first of said two inputs of said third control means with a signal presented at said second of said two inputs of said third control means, said output of said third control means providing a control signal output for the network.

Claim 14

A pneumatically operated control network in accordance with claim 1 wherein said output of said second control means provides an output for the network indicative of the signal status at said first input of said first control means provided a signal is applied to said last of said inputs of said second control means.

Claim 15

A pneumatically operated control network in accordance with claim 1 wherein said second inpuT of said first control means provides a means for resetting said first control means following the removal of said signal at said first input of said first control means.

Claim 16

A pneumatically operated control network in accordance with claim 1 further including a one-way valve connected to said output of said third control means to provide a control signal output for the control network.

Claim 17

In a pneumatically operated constant surveillance alarm system for monitoring a plurality of field points each of which present a signal so long as the field point is not in an alarm condition with an indicator for each field point and a common control network providing a control signal output at which a control output signal is normally presented with a pulsating control output signal presented at the control signal output in response to an input control signal and providing an operator controlled reset signal the combination, one for each field point, comprising a first control means having first and second inputs and an output, said first input connecting to a field point, said first control means assuming a first position in response to the presence of a signal at said first input, said first control means presenting a signal at said output when in said first position, said first control means remaining in said position upon subsequent removal of said signal at said first input, said second input connected to receive the reset signal from the common control network, said control means assuming a second position in response to the presentment of the reset signal at said second input, said first control means remaining in said second position upon removal of a signal presented to said second input provided a signal is not present at said first input; a second control means having three inputs and an output, said output of said second control means connecting with an indicator, one of said three inputs being connected with said output of said first control means, another of said three inputs being connected to said first input of said first control means, said second control means having a first position providing a connection between said one of said three inputs and said output of said second control means, said first position being provided so long as a signal is presented at said another of said three inputs, said second control means providing a second position to remove said connection between said one of said three inputs and said output of said second control means, said second position being provided when a signal is not presented at said another of said three inputs with a signal presented at the last of said three inputs, said last of three inputs connecting with the control signal output of the common control network; and a third control means having two inputs and an output, the first of said two inputs connected with said output of said second control means, the second of said two inputs connected with the output of said first control means, said third control means presenting a first position so long as a signal is presented at said first of said two inputs of said third control means, said third control means presenting a second position providing a signal at said output of said third control means, said second position being provided when a signal is not present at said first of said two inputs of said third control means with a signal presented at said second of said two inputs of said third control means; and a one-way valve connecting said output of said third control means with said central control network to provide the input signal for the central control network.

Claim 18

In a pneumatically operated constant surveillance alarm system for monitoring a plurality of field points each of which present a signal so long as the field point is not in an alarm condition with an indicator for each field point and a common control network providing a control signal output at which a control output signal is normally presented with a pulsating control output signal presented at the control signal output in response to an input control signal and providing an operator controlled reset signal the combination, one for each field point, comprising a first control means having first and second inputs and an output, said first input connecting to a field point, said first control means assuming a first position in response to the presence of a signal at said first input, said first control means presenting a signal at said output when in said first position, said first control means remaining in said position upon subsequent removal of said signal at said first input, said second input connected to receive the reset signal from the common control network, said control means assuming a second position in response to the presentment of the reset signal at said second input, said first control means remaining in said second position upon removal of a signal presented to said second input provided a signal is not present at said first input; a second control means having three inputs and an output, said output of said second control means connecting with an indicator, one of said three inputs being connected with said output of said first control means, another of said three inputs being connected to said first input of said first control means, said second control means having a first position providing a connection between said one of said three inputs and said output of said second control means, said first position being provided so long as a signal is presented at said another of said three inputs, said second control means providing a second position to remove said connection between said one of said three inputs and said output of said second control means, said second position being provided when a signal is not presented at said another of said three inputs with a signal presented at the last of said three inputs, said last of three inputs connecting with the control signal output of the common control network; and a third control means having two inputs and an output, the first of said two inputs connected with said output of said second control means, the second of said two inputs connected with the output of said first control means, said third control means presenting a first position so long as a signal is presented at said first of said two inputs of said third control means, said third control means presenting a second position providing a signal at said output of said third control means, said second position being provided when a signal is not present at said first of said two inputs of said third control means with a signal presented at said second of said two inputs of said third control means; and a one-way valve connecting said output of said third control means with said central control network to provide the input signal for the central control network.