Abstract: A method for processing an electrical signal comprises receiving an electrical signal comprising a frequency modulated signal encoding digital data; sampling a first portion of the electrical signal to obtain a plurality of samples to obtain a first sample set; determining an index value from the first sample set by assigning a value to each sample in the first sample set based upon an amplitude of the sample; comparing the determined index value with a plurality of predetermined index values to identify a first output value from a plurality of predetermined output values, each of the predetermined index values corresponding to one of the plurality of predetermined output values; and outputting an indication of the output value. Each of the predetermined output values indicates a respective frequency modulation encoded value and the first output value indicates a frequency modulation encoded value within the first portion of the electrical signal.

Abstract: A method for processing an electrical signal comprises receiving an electrical signal comprising a frequency modulated signal encoding digital data; sampling a first portion of the electrical signal to obtain a plurality of samples to obtain a first sample set; determining an index value from the first sample set by assigning a value to each sample in the first sample set based upon an amplitude of the sample; comparing the determined index value with a plurality of predetermined index values to identify a first output value from a plurality of predetermined output values, each of the predetermined index values corresponding to one of the plurality of predetermined output values; and outputting an indication of the output value. Each of the predetermined output values indicates a respective frequency modulation encoded value and the first output value indicates a frequency modulation encoded value within the first portion of the electrical signal.

Abstract: An output module comprises two management units each of which calculates the current demand for the module independently from one another. One management unit controls an output current, controller whilst the other unit monitors the current produced by the output current controller against an independently calculated demand. The output module has multiple output modules. In normal operation, each module provides a portion of the required output current, the total output current being equal to the sum of the currents output by each module. in the event of failure on one of the, modules, the other module or modules switch to providing the total current required and the failed module is switched to a fail safe mode by using an isolation circuit to switch off the output current from that module.

Abstract: A method of monitoring an analog signal output from a sensor comprising comparing the amplitude of the analog signal to a first high and low threshold, setting a primary monitoring signal to a first value when the amplitude of the analog signal exceeds the first high threshold, setting the primary monitoring signal to a second value when the amplitude of the analog signal decreases below the first low threshold, comparing the amplitude of the analog signal to a second high and low threshold, setting a secondary monitoring signal to a first value when the amplitude of the analog signal exceeds the second high threshold, setting the secondary monitoring signal to a second value when the amplitude of the analog signal decreases below the second low threshold, comparing the primary and secondary monitoring signals and determining from the comparison whether an error exists with the monitoring of the analog signal.

Abstract: This invention relates to an apparatus and method for output current control in an Industrial Process Control System, The output module comprises two management units each of which calculates the current demand for the module independently from one another. One management unit controls an output current controller whilst the other unit monitors the current produced by the output current controller against an independently calculated demand. The output module has multiple output modules. However rather than one module providing a backup for the other modules, or alternating between use of each module, in normal operation, each module provides a portion of the required output current, the total output current being equal to the sum of the currents output by each module. In the event of failure on one of the modules, the other module or modules switch to providing the total current required.

Abstract: A method of monitoring an analogue signal output from a sensor comprising comparing the amplitude of the analogue signal to a first high and low threshold, setting a primary monitoring signal to a first value when the amplitude of the analogue signal exceeds the first high threshold, setting the primary monitoring signal to a second value when the amplitude of the analogue signal decreases below the first low threshold, comparing the amplitude of the analogue signal to a second high and low threshold, setting a secondary monitoring signal to a first value when the amplitude of the analogue signal exceeds the second high threshold, setting the secondary monitoring signal to a second value when the amplitude of the analogue signal decreases below the second low threshold, comparing the primary and secondary monitoring signals and determining from the comparison whether an error exists with the monitoring of the analogue signal.

Abstract: A method for processing an electrical signal comprises receiving an electrical signal comprising a frequency modulated signal encoding digital data, sampling a first portion of the electrical signal to provide a first sample set, and determining an intermediate value from the first sample set. A first output value is selected from a plurality of stored output values based on the intermediate value, the output value indicating a frequency modulation encoded value within the first portion of the electrical signal. An indication of the obtained output value is output.