Abstract: A method for transmitting messages between a communications controller and devices in a factory process control system, wherein each device has an associated identification number which is unique to that device. A message to be transmitted is compiled, and then based on the criticality of the message, one of a standard, secure, or critical message protocols is chosen for the message; each protocol being defined to generate a message checksum for the message in a manner different from the other protocols. The generated checksum is then included in the message. Using the secure and critical protocols, a message checksum is generated from the message to be transmitted and the identification number of the intended recipient device. In the secure protocol, the message checksum is included in the message, but the identification number is not included in the message; in the critical protocol, both the message checksum and the identification number are included in the message.

Abstract: A method and apparatus for increasing the resolution and accuracy of flow measurements made by vortex flowmeters through the use of an adaptive filter. A vortex sensor signal is conditioned by a bandpass filter whose corner frequencies are dynamically altered as a function of the measured frequency of the vortex sensor signal. When the change in frequency is relatively small, the filters' corner frequencies are set to track the frequency signal in accordance with a specified bandwidth thereby improving the signal-to-noise ratio. For large frequency changes, a new frequency signal is searched for thereby avoiding tracking erroneous noise signals. Furthermore, compensation for additional or missed vortex pulses is made thereby generating a more accurate vortex frequency measurement.

Abstract: Radiant energy is transmitted to a probe element including an interior conical reflecting surface and a fluid sample chamber. Portions of the light which have been transmitted, partially attenuated, or scattered by a fluid sample in the sample chamber are directed by at least a portion of the interior conical reflecting surface to means for collecting the transmitted, partially attenuated, or scattered light. A stilling valve incorporated into the probe element enables elimination of entrained gas bubbles from the chamber. A specific application of the probe is disclosed in which a titration analyzer is combined with electro-optic signal conversion and processing circuits and a probe according to the invention to provide titration colorimetric endpoint determination in measuring the free fatty acid content of a fluid such as a edible oil or fat.

Abstract: An apparatus for determining the heating value of a fuel gas stream of variable composition utilizes a housing of high thermal conductivity defining a small volume combustion chamber, and filled with a bed of highly thermally conductive particles surrounding an electrical-resistance heater. The heater maintains the internal temperature of the chamber above the combustion point of the fuel gas, to totally combust the enclosed sample. The bed of particles transmits the heating effects of the combustion to the housing. A temperature sensor attached to the housing communicates with a feedback controller which acts to maintain the housing temperature constant, by appropriately adjusting the electrical energy supplied to the heater. Means are provided to correlate changes in the electrical energy to the heating content of the fuel sample.