Bumpless control transfer

Claim 3

A method in accordance with claim 1 wherein said local set point control of said process parameter is accomplished by comparing a local set point signal to a process measurement signal and wherein said process parameter signal is established in response to said process measurement signal.

Claim 4

A method in accordance with claim 2 wherein said automatic control set point signal is generated in response to said process parameter signal.

Claim 5

A method in accordance with claim 2 wherein said automatic control set point signal is generated in response to process signals other than said process parameter signal.

Claim 6

A method in accordance with claim 2 wherein said process parameter signal is established in response to said process measurement signal by converting a pneumatic process measurement signal to a digital electronic process parameter signal.

Claim 7

Apparatus comprising local control means for controlling a parameter of a process in response to a comparison of a first set point signal and a process measurement signal generated in response to measurement of a condition within said process, said first set point signal and said process measurement signal being of a first signal format; means for providing a preselected signal of said first signal format to said local control means for use as said first set point signal; means for generating a process parameter signal, of a second signal format which is not directly compatible with said first signal format, in response to said process measurement signal; alignment control means for generating an alignment set point signal of said second signal format in response to a comparison of said process parameter signal with a second set point signal; means for translating said alignment set point signal to said first signal format and for substituting the translated alignment set point signal for said preselected signal for use as said first set point signal; automatic control means for generating an automatic set point signal of said second signal format in response to one or more process variable measurements; means for substituting said automatic set point signal for said alignment set point signal for translation and use as said first set point signal; and means for maintaining said automatic set point signal equal to said alignment set point signal when said alignment set point signal is being translated for use as said first set point signal.

Claim 8

Apparatus comprising local control means for controlling a parameter of a process in response to a comparison of a first set point signal and a process measurement signal generated in response to measurement of a condition within said process, said first set point signal and said process measurement signal being of a first signal format; means for providing a preselected signal of said first signal format to said local control means for use as said first set point signal; means for generating a process parameter signal, of a second signal format which is not directly compatible with said first signal format, in response to said process measurement signal; alignment control means for generating an alignment set point signal of said second signal format in response to a comparison of said process parameter signal with a second set point signal; means for translating said alignment set point signal to said first signal format and for substituting the translated alignment set point signal for said preselected signal for use as said first set point signal; automatic control means for generating an automatic set point signal of said second signal format in response to one or more process variable measurements; means for substituting said automatic set point signal for said alignment set point signal for translation and use as said first set point signal; and means for maintaining said automatic set point signal equal to said alignment set point signal when said alignment set point signal is being translated for use as said first set point signal.

Claim 9

Apparatus in accordance with claim 6 additionally comprising means for establishing said second set point signal equal to the value of said process parameter signal at the time said alignment set point signal is substituted for use as said first set point signal.

Claim 10

Apparatus in accordance with claim 6 additionally comprising means for preventing substitution of said automatic set point signal for said preselected signal for use as said first set point signal.

Claim 11

Apparatus in accordance with claim 7 additionally comprising means for substituting said preselected signal for the translated alignment set point signal or the translated automatic set point signal for use as said first set point signal and means for substituting said alignment set point signal for said automatic set point signal for translation and use as said first set point signal.

Claim 12

Apparatus in accordance with claim 9 additionally comprising means for establishing said second set point signal equal to the value of said process parameter signal at the time said alignment set point signal is substituted for use as said first set point signal.

Claim 13

A method in accordance with claim 1 additionally comprising maintaining said automatic control set point signal equal to said process parameter signal when said local set point signal is being used to control said process parameter.

Claim 14

Apparatus in accordance with claim 6 additionally comprising means for maintaining said automatic set point signal equal to said process parameter signal when said preselected signal is being used as said first set point signal.