Fail Safe Mode
The SVI does not go to failsafe mode if it is functioning normally. If a problem occurs and causes the
SVI to go to the fail-safe mode, the SVI will attempt to drive the internal I/P to either high or low output
based on SVI's failsafe configuration and the appropriate failure statuses are set in the SVI. HART com-
mand #136 Read Status can be sent to the device to find out the problem. After the problem is fixed,
the device can be restarted by either resetting the power or clicking the reset button in manual mode.
These are some problems which may cause SVI go to failsafe mode.
•
Position Error
•
Position Sensor Error
•
Current Sensor Error
•
Reference Voltage Error
•
Self Check Failure
•
Software Error
When SVI is in failsafe mode, ValVue will detect it during mode transfer and display the FAIL SAFE
MODE window (figure 27). In this window, HART command #136 Read Status can be sent to the
device to determine out the problem. In this case, Position Error caused by air supply loss is the reason
the SVI failed.
Once the problem is found and solved, the SVI can be restarted by resetting the power.
Clicking the Manual button in the FAIL-SAFE MODE window switches the SVI to manual mode. From
there you can click the reset button to reset the device.
If the problem is caused by inappropriate configuration parameters, click the Manual button in the FAIL
SAFE MODE window and then click the Configure button to enter into configuration mode.
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Figure 27. Fail Safe
Mode Window