Industrial process field device with low power optical isolator
First Claim
1. An industrial process control field device, comprising:
- a process variable transducer configured to sense or control a process variable;
field device circuitry configured to couple to the process variable transducer and communicate on an industrial process control loop, the field device circuitry including an optical isolator comprising;
transmit circuitry on a first side of a galvanic isolation configured to transmit an optical signal across the isolation, the optical signal which is pulsed on and off; and
receive circuitry on a second side of the galvanic isolation configured to receive the optical signal and responsively provide a secondary side output based upon the optical signal, the receive circuitry including an optical sensor which enters an “
on”
state when it receives a pulse in the optical signal and is otherwise in an “
off”
state, and an amplifier coupled to the optical sensor which only amplifies the secondary side output when the optical sensor enters the “
on”
state to thereby reduce power consumption, wherein the receive circuitry includes a comparator which provides an output based upon an output from the optical sensor and the output from the optical sensor is AC coupled to the comparator to thereby reduce power consumption.
2 Assignments
0 Petitions
Accused Products
Abstract
An industrial process control field device includes a process variable transducer configured to sense or control a process variable. Field device circuitry is configured to couple to the process variable transducer and communicate information related to the process variable to another location. The field device circuitry includes an optical isolator having transmit circuitry on a first side of a galvanic isolation configured to transmit an optical signal which is pulsed on and off across the isolation. Receive circuitry is located on a second side of galvanic isolation and configured to receive the optical signal with an optical sensor. The optical sensor enters an “on” state when it receives a pulse and is otherwise in an “off” state. The receive circuitry provides a secondary side output based upon the received optical signal. The receive circuitry enters in a low power state when the optical sensor is in the “off” state.
-
Citations
14 Claims
-
1. An industrial process control field device, comprising:
-
a process variable transducer configured to sense or control a process variable; field device circuitry configured to couple to the process variable transducer and communicate on an industrial process control loop, the field device circuitry including an optical isolator comprising; transmit circuitry on a first side of a galvanic isolation configured to transmit an optical signal across the isolation, the optical signal which is pulsed on and off; and receive circuitry on a second side of the galvanic isolation configured to receive the optical signal and responsively provide a secondary side output based upon the optical signal, the receive circuitry including an optical sensor which enters an “
on”
state when it receives a pulse in the optical signal and is otherwise in an “
off”
state, and an amplifier coupled to the optical sensor which only amplifies the secondary side output when the optical sensor enters the “
on”
state to thereby reduce power consumption, wherein the receive circuitry includes a comparator which provides an output based upon an output from the optical sensor and the output from the optical sensor is AC coupled to the comparator to thereby reduce power consumption. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method of communicating data in an industrial process control field device, comprising:
-
sensing or controlling a process variable with a process variable transducer; communicating on an industrial process control loop, the communication related to the sensing or controlling; transmitting data from a first side of galvanic isolation with an optical signal by pulsing the optical signal on and off; receiving the optical signal with receive circuitry on a second side of galvanic isolation and responsively providing a receive circuit output based upon the optical signal by causing an optical sensor to enter an “
on”
state when it receives a pulse in the optical signal and otherwise remaining in an “
off”
state, and amplifying the optical sensor output only when the optical sensor enters the “
on”
state to thereby reduce power consumption;comparing the output from the amplifier using a comparator; and AC coupling the output from the optical sensor to the comparator to thereby reduce power consumption. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
Specification