> Introduction :: Pantech's Auto Manual Controllers, series 881 are designed to control output going to control valve, with or without the process controller. It can operate in AUTO/MANUAL both modes depending upon field condition. Model 881P is an Auto Manual Control station with digital display. It accepts current input of 4 – 20mA DC from a controller (or DCS) and directs it to output in auto mode. The output can be alternatively controlled in manual mode through UP or DOWN push buttons. Auto to manual transfer is bumpless. Even if the controller output drops to zero abruptly, A/M station goes to manual mode automatically. Even in case of failure of A/M station, the controller continues its control in auto mode. The optional auto bias feature of the instrument allows even manual to auto transfer bumpless. The bias is set automatically in manual mode to allow this bumpless transfer and then it can be changed by the same push buttons in auto mode. External feedback signal o/p from the A/M station allows controller to track A/M output in manual mode. The rates of change of output (in manual mode) and bias (in auto mode) are 1% and 10% per sec. The display indicates output or input/bias in percentage through 3 ½ digit red LED display. The
modules incorporate low drift operational amplifiers and industrial
grade components. Burn in of each module ensures a long trouble
free operation. > Specifications ::
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