Yokogawa Data Acquisition with PID Control CX2000 User Manual

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IM 04L31A01-01E

Explanation of Functions

PV Tracking ON/OFF

The PV tracking function is used to prevent radical changes in the PV.
When the PV tracking function is enabled (ON), the SP is forced to match the PV once in
the following cases.
• When powering up.
• When switching from manual (MAN) operation mode to auto (AUTO) operation mode.
• When switching from operation stop to operation run.
• When switching the SP number.
The SP is matched against the PV once, and then returns to the original SP according to
the “target setpoint ramp-rate (rate of change)” that is specified separately. When using
the PV tracking function, make sure to set the SP ramp-rate (rate of change). The ramp-
rate is 0 when it is OFF. Consequently, the PV tracking function does not operate in this
case. PV tracking function ON/OFF setting: ON or OFF (the initial value is OFF)
• When PV tracking is OFF

MAN

AUTO

Time

Mode switching

• When PV tracking is ON

MAN

AUTO

Follows the target setpoint
ramp-rate

Time

Mode switching

Burnout

When the PV input is a thermocouple or standard signal, a burnout action can be
specified. When a burnout is detected, the PV is fixed to positive overrange (when the
burnout detection action is set to “UP”) or negative overrange (when the burnout
detection action is set to “DOWN”), and the control output is set to preset output.

Reference Junction Compensation

You can select whether to use the internal reference junction compensation function of
the CX2000 or an external reference junction compensation function. When using an
external reference junction compensation, set an appropriate reference junction
compensation voltage. For example, if the reference junction temperature of the external
reference compensation is T

°C, set the reference compensation junction voltage to the

thermoelectromotive force of the 0-°C reference of T

°C.

1.4 PV Input Related Settings