Technical Specifications

137
Self Test Explanation
Diagnostic Services
Self Test Explanation
Internal Gain This describes the forward gain of control valve system. The
forward gain is the gain of the I/P, control relay, valve actuator
(Spring range), and linkage combined. The unit for this parame-
ter is rad/mA. (The input signal of I/P is mA, the output signal of
linkage is rad). The Internal Gain is based upon the Measured
Gain.
Measured Gain This is measured by the Auto Tune function (units: mA/rad).
Valve TC This describes how fast the control relay can drive the air actua-
tor (units: seconds). This parameter is measured by the Auto
Tune function.
Valve Hysteresis This describes the hysteresis of the control valve (units: %).
This parameter is measured by the Auto Tune function.
Valve Slip Width This describes the slip width of control valve (units: %). The
stem of the control valve makes an abrupt movement when the
pneumatic actuator breaks the friction of the valve packing. Slip
width is the value of abrupt movement of the stem.
Measured Exhaust
Pressure
This describes air pressure. This parameter is available only in
the AP option (with pressure sensor). The units are determined
by unit index of Spring Range. This parameter is measured by
the Auto Tune function. It is the value of actuator pressure when
the valve is at the 0% mechanical stop. The parameter is used
for diagnostics only; not for tuning or control.
Measured Supply
Pressure
This describes supply pressure. The units for this parameter are
determined by unit index of Spring Range. This parameter is
available only in the AP option. This parameter is measured by
the Auto Tune function. It is the value of actuator pressure when
the valve is at the 100% mechanical stop. The parameter is
used for diagnostic only; not for tuning or control.
Measured Spring
Range - Upper
This describes upper range value of the control valve spring
range. The units for this parameter are determined by unit index
of Spring Range. This parameter is available only in the AP
option. This parameter is measured by the Auto Tune function.
The parameter is used for diagnostics only; not for tuning or
control.
Measured Spring
Range - Lower
This parameter is the lower range value of the control valve
spring range. The units for this parameter are determined by
unit index of Spring Range. This parameter is available only in
the AP option. This parameter is measured by the Auto Tune
function. This parameter is used for diagnostics only; not for
tuning or control.