Yokogawa YVP20S - Manual (Page 129)

14-3
IM 21B04C50-01E
<Toc> <Ind> <14. DIAGNOSTIC SERVICES>
14.2 Self Check
WARNING
Performing Self Check will stroke the valve. Do not perform while the valve is controlling the
process. Keep clear of moving valve parts.
The Self Check page of the diagnostics tests the performance parameters that are used to
determine the position control parameters. The test will run autotune but will not change
any parameters. The parameters display provides two views for comparison, the left half is
the original data before performing this test, while the right half shows the resulf of the Self
Check test.
Figure 14.4 Self Check
Press GO to start the test.
WARNING
The control valve will move and must be isolated from the process. Keep clear of moving
parts.
The result of the self check will be displayed in the box next to the GO button. Note any
error messages.
(1) Internal Gain
This parameter 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 parameter 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.