Abstract: Provided is a method in a control system that is configured to provide command information to environmental adjustment equipment. The control system includes a plurality of user interface devices wherein each user interface device is configured to select an operating mode for a plurality of monitored areas in a building and wherein each user interface device is located in a different one of the monitored areas. The method comprises detecting a mode change request at a first user interface device for a first monitored area and executing the mode change request for the first monitored area while retaining a prior selected mode for another monitored area that was selected using a different user interface device when for each monitored area the environmental adjustment equipment includes a throttling device for controlling the flow of conditioned medium provided to the monitored area.

Abstract: A method in an interface control device for a control system that provides control instruction to environmental adjustment equipment is provided. The method comprises receiving user input via an input section in the interface control device and simultaneously displaying via an output indication section in the interface control device an operating mode selection for use during a timed period, an operating mode selection for use during an untimed period, and a predetermined timed period length in the form of a duration or an ending clock time. The method further comprises providing instructions to a controller that instructs the environmental adjustment equipment to operate in a manner consistent with the operating mode selections for the timed period and the untimed period and the predetermined timed period.

Abstract: A method and circuitry for ensuring proper connections of a multi-wired cable bridging two electrical components in a programmable logic controller (PLC) system. The method involves: generating a pre-specified voltage level when the cable is properly connected, testing for the existence of this pre-specified voltage level, and generating an error signal if the pre-specified voltage level is not detected. The error signal generated by a component causes the component to electronically switch off its data connection via the multi-wired cable with the other component, and may cause the component to reset itself.

Abstract: Circuitry for protecting a first electrical system when connected to a second electrical system via a bus which provides a current-carrying signal to the first electrical system and includes a reset signal which is monitored by the second electrical system. The circuitry includes a capacitor connected to the current-carrying signal of the bus. A first switch is electrically connected between a node of the capacitor and a ground point. The first switch is closed when the first electrical system is powered-up and open when the first electrical system is powered down. A second switch is electrically connected between the reset signal of the bus and the ground point. The second switch closes due to the energy accumulated by the capacitor when the first switch is open.

Abstract: A system and method is provided for selecting a test load and/or bias resistor utilized in an expandable load system employing a backup power source. The test load and/or bias resistor is selected based on the actual load present in the expandable system. The backup power source is periodically tested during normal operation of the expandable load system utilizing the test load. A test load is provided that is sized for the actual load of a local load under worse case conditions. If an expansion load is connected to the local load the test load is adjusted, so that the test load is based on the actual load of the local load and the expansion load. Additionally, a bias resistance can be provided for driving a switch that allows power to be provided to the local load during power loss mode. If an expansion load is connected to the local load, the bias resistance is adjusted to correspond to a bias resistance necessary to provide the current for the actual load of the local load and the expansion load.

Abstract: A circuit card of an industrial controller may be removed or inserted under power without loss of memory or disturbance to the power supplies of other modules through the use of a power failure signal derived from shortened pins on the connector between the card and the industrial controller. The power failure signal activates a timer delaying connection of the board components to power until the physical connection between the card and the industrial controller has stabilized. At this time current drain is ramped up by a controlling series FET. Upon removal of the card, the power failure signal causes outputs of an on-board microprocessor to be pulled to particular states necessary to prevent disturbance of a battery backed-up RAM and to eliminate current flow through protection diodes on other memory type devices attached to the microprocessor.

Abstract: Data is exchanged between two modules of a programmable controller by originator module writing the information in an interface memory in one of the modules and the recipient module reading the information from the memory. An initialization procedure is performed before any information is exchanged in that manner. The module containing the memory writes the size of the memory for reading by the other module. Sets of test data are stored in the memory by each module and checked by the other module to determine if data can be passed accurately between the modules in both directions. Then data identifying the type of one of the modules is exchanged to insure that the other module knows the type of module with which it is dealing.

Abstract: A programmable controller is customized for a specific application by a function card inserted into a socket of a processor module on the controller. The function card can perform one or more tasks and may be used with different types of programmable controllers. Before the card can be used by a given programmable controller an initialization procedure must be performed to determine if the processor module and the card are compatible. As part of this procedure information about the operation of the given programmable controller is sent to the card. The card also contains functional information for each of its tasks the card provides. The functional information is sent to the processor module during the initialization procedure to enable the module to utilize the card.

Abstract: An inter-processor communication module is inserted into a slot of an equipment rack of the type used to connect I/O modules to system processors in a programmable controller. Using two of the inter-processor communication modules in two respective racks, a supervisory processor is connected to two respective local area processors in a distributed control system. The inter-processor communication module has a serial channel controller that connects to the supervisory processor through a serial I/O port and a serial communication channel to communicate blocks of I/O status data. The serial channel controller is coupled to a backplane controller through a common memory and arbitration circuitry to exchange blocks of I/O status data. The backplane controller, which is also a part of the inter-processor communication module, plugs into the backplane of the rack and exchanges blocks of I/O status data with a local area processor.

Abstract: A method and apparatus for access to a programmable controller at a remote location. A peripheral device with a peripheral processor is connected to a port on an I/O module. Blocks of discrete and block transfer data are transferred to and from a common memory in the I/O module where the data is accessible to a serial communication controller that interfaces the module to a high speed serial data channel. Asynchronous communication is provided between the serial communication controller and the peripheral device using a circular buffer in the common memory. Timing considerations are also disclosed.

Abstract: An improved stepping motor controller is comprised of a programmable controller provided with a pair of input/output circuits for controlling the stepping motor in accordance with move data blocks from the programmable controller's central processing unit (CPU) containing user-programmed stepping motor move profile parameters including a user-programmed stepping motor acceleration interval for stepping motor acceleration, user-programmed stepping motor deceleration interval for stepping motor deceleration and a user-programmed stepping motor final position. The pair of input/output circuits includes a master controller module and at least one and up to three satellite output modules. The master controller module is coupled to the programmable controller CPU to read and process the move data blocks to generate satellite move set data blocks for each satellite output module.