5.14
Example 2 - Flow Regulation
eegend
1 DPRSOO Controller
2 I/P convewr
3 Control Valve
4 Throttle
5 Shut-off Valve
6 Valve Block
7 Differential
Pressure *ensor
In the following figure the process requirement is for the normally
closed valve to open if the control pressure fails. The valve also
closes if the flow rate increased. In either case an increasing process
value yields an increasing output signal from the controller, The
controller must be configured for direct output.
Alarm and Fault Indications
The controller can monitor the process value or the deviation between
the process and setpoint values and internal functions.
514.1
Fault Indication
There are two types of fault indications, based on the severity of the
error. Error code values less than 100 are controller fatal faults that
effect the basic operation of the controller. These errors are indicated
as Err n on the digital display and DO3 and DO4 are simultaneously
activated.
May 1991
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