Mettler Toledo M300 FLOW Especificaciones descargar pdf (Pagina 43)

Transmitter O

M300 43

M300

Printed in Switzerland 52 121 305

10 PID setup

(PATH: Menu/PID Setup)

PID control is proportional, integral and derivative control action that can provide smooth

regulation of a process. Before conﬁguring the transmitter, the following process characteristics

must be identiﬁed.

Identify the control direction of the process:

Deaeration-direct acting where increasing measurement produces increasing control output

such as controlling the feed of

a reducing agent to remove oxygen from boiler feedwater

Aeration-reverse acting where increasing measurement produces decreasing control output,

such as controlling an aerator blower speed to maintain a desired O

concentration in

fermentation or wastewater treatment

Identify the control output type based on the control device to be used:

Pulse Frequency-used with pulse input metering pump

Pulse Length-used with solenoid valve

Analog-used with current input device such as electric drive unit, analog input metering pump

or current-to-pneumatic (I/P) converter for pneumatic control valve

Default control settings provide linear control which is appropriate for dissolved oxygen. The

non-linear control settings are used in pH/ORP models of this transmitter. Therefore ignore

settings of deadband and corner points in the Tuning Parameter section below.

To counteract this, the instrument allows for adjustable non-linear control with settings of

a deadband around the setpoint, corner points further out and proportional limits at the ends

of control as shown in the ﬁgure below. Determine the appropriate settings for each of these

control parameters based on the shape of the process titration curve.

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Mettler Toledo M300 FLOW Especificaciones Pagina 43