Abstract: The method of downloading application information from a host device to a field device over a network providing communication and power to the field device, the method including the steps of stopping the normal data processing of a connected control device, halting operation of device components not critical to the download operation, reducing the operating frequency of a microprocessor included in the field device and transmitting a new device application over the network.

Abstract: A data processing apparatus having a pipeline computer architecture with an input pipeline latch is disclosed. The data processing apparatus includes an ALU that executes a plurality of processing instructions. At least some of the instructions have an immediate data format including a field for intermediate data and a field for specifying a destination for an output. The ALU uses two operands for performing at least some of the instructions having the immediate data format. The ALU conditionally accepts either the contents of the input pipeline latch or the ALU output of the previous instruction as a second operand to an immediate instruction depending on the destination specified in the destination field of the previous instruction.

Abstract: An integrated circuit read-only-memory with low power requirements, including a plurality of information storage memory cells and a decoder. The circuit operated in response to a selected address input and a control input to the decoder to direct and generate output of information stored in a selected one of the memory cells.

Abstract: A microprocessor control (10, 24) has one or more temperature responsive thermistor sensors (20, 26, 28) used to provide temperature inputs to control operation of a temperature control system. The microprocessor control subjects the thermistor sensors to a series of diagnostic tests prior to reading the thermistor sensors, the tests including short and open circuits, shorts to ground or power and leakage paths to ground. The thermistors, along with a reference resistor (R11, R26) form an RC charge circuit with a capacitor (C6, C6'). The capacitor is charged through each thermistor and reference resistor for selected open and short tests while a watch dog timer is used to determine the time taken to charge the capacitor via a timer capture port coupled to the capacitor.

Abstract: An electric control for gas furnaces which controls a two speed main blower fan and an induction draft fan based on inputs from a room thermostat, a high limit and an ignition control including a gas valve. The control has a circuit board having a power supply for providing 24 volts DC current source to drive DC relays and a 5 volt DC power source to power a microprocessor. 24 volt AC input signals are coupled to the input ports of the microprocessor through current limiting resistors and to AC ground through pull down resistors. AC ground is also connected to the IRQ port of the microprocessor. The output ports of the microprocessor are connected to a relay driver which in turn is connected to the relays. Several breakaway tabs in the board provide optional features such as eliminating a normally provided draft delay timing function. Test pads are provided on the board so that the board can be tested during manufacture.

Abstract: An electronic control for gas furnaces controls a two speed main blower fan and an induction draft fan based on 24 volt input signals from a room thermostat, a high limit and an ignition control including a gas valve. The input signals are coupled to input ports of a microprocessor through current limiting resistors and to AC ground through pull down resistors. AC ground is also connected to the IRQ port of the microprocessor. Output ports of the microprocessor are connected to a relay driver which in turn is connected to relays for energizing and de-energizing the fans. The control calibrates itself on a continuing periodic basis to read the AC inputs synchronously at the peak of their wave and can switch the relays asynchronously based on the Real Time Clock of the microprocessor or can be switched synchronously by providing a selected delay so that contact engagement and disengagement occurs at or near the zero crossing of the AC line voltage wave form.

Abstract: An apparatus for measuring the flow of a liquid through a conduit by observing the transit of an injected gas bubble through the conduit. A gas source, responsive to the pressure of the liquid in the conduit, supplies gas at a predetermined pressure to a gas injector. This allows the gas injectors to inject a predetermined volume of gas into the conduit, largely independent of the absolute pressure of the liquid. An image, produces a conduit image representative of the gas bubble and the liquid in the conduit, comprising a plurality of elements corresponding to a plurality of predetermined locations along the conduit. A timer responsive to the conduit image produces a plurality of transit times substantially equal to the times required for the gas bubble to transit between adjacent predetermined locations. A time analyzer and indicator are included for analyzing the plurality of transit times and indicating the flow of the liquid through the conduit.

Abstract: An electric control for gas furnaces which controls a two speed main blower fan and an induction draft fan based on inputs from a room thermostat, a high limit and an ignition control including a gas valve. The control has a circuit board having a power supply for providing 24 volts DC current source to drive DC relays and a 5 volt DC power source to power a microprocessor. 24 volt AC input signals are coupled to the input ports of the microprocessor through current limiting resistors and to AC ground through pull down resistors. AC ground is also connected to the IRQ port of the microprocessor. The output ports of the microprocessor are connected to a relay driver which in turn is connected to the relays. Several breakaway tabs in the board provide optional features such as eliminating a normally provided draft delay timing function. Test pads are provided on the board so that the board can be tested during manufacture.