Systems and/or devices for providing an isolated analog output or analog input

1. A system comprising:

a voltage-to-frequency converter adapted to:

receive an analog input signal that represents a sensor-detected physical property;

convert said analog input signal to a converted signal having a constant voltage and a frequency value that varies according to a voltage value of said analog input signal; and

transmit said converted signal across an isolation device; and

a frequency-to-voltage converter adapted to:

receive said converted signal;

convert said converted signal to a recovered analog input signal having a voltage value that varies according to said frequency value of said converted signal;

transmit said recovered analog input signal to a programmable logic controller;

a second voltage-to-frequency converter adapted to:

receive an analog output signal adapted to control an actuator from the programmable logic controller;

convert said analog output signal to a converted signal having a constant voltage and a frequency value that varies according to a voltage value of said analog output signal;

transmit said converted signal across an isolation device; and

a second frequency-to-voltage converter adapted to:

receive a converted signal;

convert said converted signal to a recovered analog output Signal having a voltage value that varies according to said frequency value of said converted output signal; and

transmit said analog output signal to said actuator; and

an information device communicatively coupled to the programmable logic controller via a network, the information device including a user program adapted to

monitor one or more activities of the programmable logic controller, or

create, edit, compile or transmit a control program.

2. The system of claim 1 , wherein:

the programmable logic controller adapted to process said recovered analog input signal to obtain an input value for said sensor-detected physical property.

3. The system of claim 1 , comprising:

an analog input module adapted to convert said recovered analog input signal to a digital input signal.

4. The system of claim 1 , wherein:

the programmable logic controller adapted to process a digital signal, said digital signal encoding an input value obtained from said recovered analog input signal, said input value corresponding to said sensor-detected physical property.

5. The system of claim 1 , comprising:

a human machine interface adapted to render an input value corresponding to said sensor-detected physical property.

6. The system of claim 1 , wherein:

said isolation device is an opto-isolator.

7. The system of claim 1 , wherein:

said isolation device is a transformer.

8. A system comprising:

a voltage-to-frequency converter adapted to:

receive an analog output signal adapted to control an actuator from a programmable logic controller;

convert said analog output signal to a converted signal having a constant voltage and a frequency value that varies according to a voltage value of said analog output signal;

transmit said converted signal across an isolation device; and

a frequency-to-voltage converter adapted to:

receive said converted signal;

convert said converted signal to a recovered analog output signal having a voltage value that varies according to said frequency value of said converted signal;

transmit said analog output signal to said actuator; and

an information device communicatively coupled to the programmable logic controller via a network, the information device including a user program adapted to

monitor one or more activities of the programmable logic controller, or

create, edit, compile or transmit a control program.

9. The system of claim 8 , wherein the programmable logic controller is adapted to create said analog output signal.

10. The system of claim 8 , further comprising:

an output module adapted to create said analog output signal.

11. The system of claim 8 , wherein the programmable logic controller adapted to provide an analog output value corresponding to said analog output signal to a human machine interface.

12. The system of claim 8 , further comprising:

a human machine interface adapted to render an analog output value corresponding to said analog output signal.

13. The system of claim 8 , further comprising:

said isolation device is an opto-isolator.

14. The system of claim 8 , further comprising:

said isolation device is a transformer.

15. The system of claim 8 , further comprising:

a voltage-to-frequency converter adapted to:

receive an analog input signal that represents a sensor-detected physical property;

convert said analog input signal to a converted signal having a constant voltage and a frequency value that varies according to a voltage value of said analog input signal; and

transmit said converted signal across an isolation device; and

a frequency-to-voltage converter adapted to:

receive said converted signal;

convert said converted signal to a recovered analog input signal having a voltage value that varies according to said frequency value of said converted signal; and

transmit said recovered analog input signal to the programmable logic controller.

16. A method comprising:

receiving an analog input signal that represents a sensor-detected physical property;

converting said analog input signal to a converted signal having a constant voltage and a frequency value that varies according to a voltage value of said analog input signal;

transmitting said converted signal across an isolation device;

on a downstream side of said isolation device, converting said converted signal to a recovered analog input signal having a voltage value that varies according to said frequency value of said converted signal;

transmitting said recovered analog input signal to a programmable logic controller;

in a voltage-to-frequency converter:

receiving an analog output signal adapted to control an actuator from the programmable logic controller;

converting said analog output signal to a converted signal having a constant voltage and a frequency value that varies according to a voltage value of said analog output signal;

transmitting said converted signal across an isolation device;

in a frequency-to-voltage converter:

receiving said converted signal;

converting said converted signal to a recovered analog output signal having a voltage value that varies according to said frequency value of said converted signal; and

transmitting said analog output signal to said actuator; and

communicatively coupling an information device to the programmable logic controller via a network, the information device including a user program; and

monitoring with the user program one or more activities of the programmable logic controller, or

using the user program to create, edit, compile or transmit a control program.