Digitally compensated process transmitter with minimal dead time
First Claim
Patent Images
1. A process transmitter comprising:
- a sensor for producing a process signal that is a function of a process parameter;
a first signal path in which the process signal is digitally compensated to produce a digitally compensated process signal;
a second signal path in which the process signal is digitally filtered to produce a digitally filtered process signal and subject to less delay than the first signal path; and
an output summing circuit for summing the digitally compensated process signal and the digitally filtered process signal to produce a fast digital compensated process signal, wherein the second signal path is synchronized to the first signal path so that a decaying portion of the digitally filtered process signal cancels out a decaying portion of the digitally compensated process signal when summed at the output summing circuit.
1 Assignment
0 Petitions
Accused Products
Abstract
A processor transmitter includes a sensor, a first signal path, a second signal path, and an output summing circuit. The sensor produces a process signal that is a function of a process parameter. The first signal path digitally compensates the process signal. The second signal path digitally filters the process signal and subjects the process signal to less delay than the first signal path. The output summing circuit sums the digitally compensated process signal from the first signal path and the digitally filtered process signal from the second signal path to produce a fast digital compensated process signal.
12 Citations
20 Claims
-
1. A process transmitter comprising:
-
a sensor for producing a process signal that is a function of a process parameter; a first signal path in which the process signal is digitally compensated to produce a digitally compensated process signal; a second signal path in which the process signal is digitally filtered to produce a digitally filtered process signal and subject to less delay than the first signal path; and an output summing circuit for summing the digitally compensated process signal and the digitally filtered process signal to produce a fast digital compensated process signal, wherein the second signal path is synchronized to the first signal path so that a decaying portion of the digitally filtered process signal cancels out a decaying portion of the digitally compensated process signal when summed at the output summing circuit. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A process transmitter further comprising:
-
a sensor for producing a process signal that is a function of a process parameter; a first signal path in which the process signal is digitally compensated to produce a digitally compensated process signal; a second signal path in which the process signal is digitally filtered to produce a fast digitally filtered process signal and subject to less delay than the first signal path; a third signal path in which the process signal is digitally filtered and inverted to produce a delayed inverted process signal, the third signal path subject to greater delay than the second signal path; an intermediate summing circuit for adding the delayed inverted process signal to the second path to produce a digitally filtered process signal; and an output summing circuit for summing the digitally compensated process signal and the digitally filtered process signal to produce a fast digital compensated process signal. - View Dependent Claims (7, 8, 9)
-
-
10. A process transmitter comprising:
-
a sensor for producing a process signal that is a function of a process parameter; an analog-to-digital converter to digitize the process signal to produce a digital process signal; a first digital low pass filter to filter the digital process signal to produce a fast filtered process signal; a second digital low pass filter to filter the fast filtered process signal to produce a slow filtered process signal, the second digital low pass filter having a lower update frequency than the first digital low pass filter; a first digital processor to digitally compensate the slow filtered process signal to produce a digitally compensated process signal;
the first digital processor creating a delay in the digitally compensated process signal;an inversion circuit to invert the slow filtered process signal to produce an inverted process signal; a matching circuit to create a delay in the inverted process signal to produce a delayed inverted process signal; an intermediate summing circuit to sum the fast filtered process signal and the delayed inverted process signal to produce a digitally filtered process signal; and an output summing circuit to sum the digitally filtered process signal and the digitally compensated process signal to produce a fast digital compensated process signal. - View Dependent Claims (11, 12, 13, 14, 15)
-
-
16. A method for producing process transmitter output having an overall dynamic response closely following a sensed process parameter:
-
producing an analog process signal that is a function of the sensed process parameter; digitizing the analog process signal to produce a digital process signal; compensating the digital process signal to produce a digitally compensated process signal; filtering the digital process signal to produce a digitally filtered process signal; summing the digitally compensated process signal and the digitally filtered process signal to produce a fast digital compensated process signal, wherein the digitally filtered process signal is synchronized to the digitally compensated process signal so that a decaying portion of the digitally filtered process signal cancels out a decaying portion of the digitally compensated processed signal when they are summed to produce the fast digital compensated process signal; and producing a process transmitter output responsive to the fast digital compensated process signal. - View Dependent Claims (17, 18)
-
-
19. A method for producing process transmitter output having an overall dynamic response closely following a sensed process parameter:
-
producing an analog process signal that is a function of the sensed process parameter; digitizing the analog process signal to produce a digital process signal; compensating the digital process signal to produce a digitally compensated process signal; filtering the digital process signal to produce a digitally filtered process signal; summing the digitally compensated process signal and the digitally filtered process signal to produce a fast digital compensated process signal; and producing a process transmitter output responsive to the fast digital compensated process signal; wherein filtering the digital process signal to produce a digitally filtered process signal includes; filtering the digital process signal with a fast digital low pass filter to produce a fast filtered process signal; filtering the fast filtered process signal with a slow digital low pass filter to produce a slow filtered process signal, the slow digital low pass filter having a lower update frequency than the fast digital low pass filter; delaying and inverting the slow filtered process signal to produce a delayed inverted process signal; and summing the fast filtered process signal and the delayed inverted process signal to produce the digitally filtered process signal; and wherein compensating the digital process signal to produce a digitally compensated process signal includes; filtering the digital process signal with the fast digital low pass filter to produce the fast filtered process signal; filtering the fast filtered process signal with the slow digital low pass filter to produce a slow filtered process signal; and digitally compensating the slow filtered process signal to produce the digitally compensated process signal. - View Dependent Claims (20)
-
Specification