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Partial Stroke Test Diagnostics
The SVI II ESD is capable of partially stroking the valve to detect failures in the final control
element assembly. PST is configured using the pushbutton display or through ValVue ESD.
The PST can be configured to automatically start or be initiated by setting current input to
16.4 mA, local control panel pushbutton, or field initiated by an operator. When configured to
run automatically or when initiated through a safety rated logic solver, additional diagnostic
credit can be taken for the PST.
PST Configuration
Before running PST, you must configure the following parameters: travel, maximum pressure,
maximum time, ramp speed, and spring. You can configure PST parameters from the
pushbutton display or using ValVue ESD. Refer to Table 10 on page 99 for PST configuration
parameters.
PST Configuration with Display Menu
When using the LCD display to configure PST:
1. Access PST Configuration (PST CONF) menu. Refer to Figure 62 on page 102 for menu
structure.
2. Scroll through each PST parameter and adjust accordingly. PST Configuration menu is
displayed in Figure 70 on page 117. The adjustable parameters are as follows:
PST Travel - range is in a percentage of 100% travel over which you want partial stroke
testing to occur.
Minimum Pressure - minimum pressure in engineering units allowed during PST.
Maximum Time - allowed time in seconds for partial stroke.
Ramp Speed - travel speed in % of PST travel per second.
Adjust PST configuration parameters by:
a. Opening PST CONF press * to move into PST configuration menus.
b. Moving through PST configuration menus by pressing + until the appropriate menu
appears.
c.
Pressing * to activate menu.
d. Setting values using the +/- button to adjust value.
e.
Pressing * to leave the active menu adjustment and + button to move to next menu.
116 |
=GE Oil & Gas
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Troubleshooting
