FOXBORO 743CB-DF 743CB Series
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Author:kongjiangauto
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Time :2019-04-26
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FOXBORO 743CB-DF 743CB Series
RS-485 SERIAL COMMUNICATIONS INTERFACE This controller is equipped with an RS-485 serial port for communication with most host computers, either directly or via an RS-232/RS-485 converter or equivalent accessory. Protocol conforms to ANSI Specification X3.28-1976, Subcategory E3. Using the Foxboro Model F6501A converter, up to 90 controllers can be accommodated with a single host communication port. Serial communications capability includes uploading/downloading of configuration, setting of Auto/Manual (A/M) or Remote/Local (R/L) status and manual output and local setpoint values, polling of all inputs, outputs, and totalizers, and writing as well as reading of all configurable parameters. Both control loops are accommodated. The user can also select parity, and panel, workstation (host), or “both” priority. COMPUTATIONAL CAPABILITY This controller performs up to three independent calculations. The variables may include the results of other calculation blocks, scaled and conditioned inputs, and other internal control signals. An equation is entered from the keypad one character at a time following the usual rules of algebra and a few easy-to-learn rules. The result of this flexibility is exceptional computational capability in a single station controller. SIMPLIFIED CONFIGURATION AND OPERATION Because of its flexibility, this controller is easily configured to meet the most exacting process requirements. All operating functions are examined and/or changed by keystrokes. Interactive prompting simplifies setting the adjustable parameters. COMPLETE SECURITY The operator has keypad access to read the values of inputs, alarm and limit settings, and the operating configuration. However, the operator can adjust only those settings which were specified as operator- adjustable when the controller was configured. A passcode must be entered from the keypad to enable adjustment of the remaining parameters. In addition, a keypad disable jumper, accessible from inside the tamper resistant enclosure, is provided. This passcode is determined by an authorized person at the time the controller is configured. Thus, only those who have been given this passcode can change any of the protected parameters. BOOLEAN LOGIC CAPABILITY There are five single gates and five dual gates. Each gate is configured by selecting the logic and then selecting the source of each input. Gates 0 through 4 are the single input gates and are configured DIRECT or NOT by the user. Gates 5 through 9 are the dual input gates and the user selects one of the following logic types for each one: OR, NOR, AND, NAND, XOR, or XNOR. DYNAMIC COMPENSATION The result of a dedicated calculation block can be passed through a dynamic compensator, prior to distribution. The dynamic compensator provides lead/lag, impulse, and dead time functions, each with its individual follow (bypass) switch. Functionally, dead time precedes lead/lag and is the input to the lead/lag function. Utilizing the dynamic compensator and the follow switches, feedforward and other complex control applications are easily and efficiently handled.