System and method for limiting energy in an industrial control system
View Patent ↗Systems and methods for limiting heating to prevent explosions in a gaseous environment containing an industrial control system are described. A method may include controlling heating in an electrical circuit component in response to a circuit failure so as to avoid reaching a temperature at or above a flash point of a gaseous component of the gaseous environment.
1. An energy-limiting module for industrial controller, comprising:
first and second signal lines disposed to provide a voltage to a field transducer, the field transducer being associated with a process parameter;
a temperature-dependent limiter coupled between a supply voltage and the first signal line, the temperature-dependent limiter being configured to limit thermal energy in the module to a temperature below the flash temperature of any gaseous component of an operating environment the industrial controller is configured to operate in, in the event of a fault;
a voltage limiter coupled to the first signal line so as to limit the voltage provided to the field transducer; and
a current to voltage translator coupled to the second signal line, wherein the current to voltage translator is configured with a resistor coupled between the field transducer and a V-reference terminal so as to generate an output voltage signal proportional to a field current provided from the field transducer.
2. The module of claim 1 , further comprising a processor coupled to an output of the field transducer and an actuator coupled to the processor, wherein the processor is disposed to provide a control signal to the actuator responsive to an output of the field transducer.
3. The module of claim 1 wherein the transducer is selected from a group of a temperature transducer, a pressure transducer and a flow transducer.