Flowserve 3400IQ Digital Positioner - Manual (Page 39)

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Logix 3400IQ Digital Positioner FCD LGENIM3401-00 – 06/06
flowserve.com
9. Set RAMP_RATE to desired value (typically 100).
10. Write value to the Logix 3400IQ digital positioner.
11. In SIG_FLAGS, select BEGIN_SIG.
12. Write value to the Logix 3400IQ digital positioner.
13. The valve will stroke to the beginning position, as defined by SIG_START and will begin ramping
to the desired ending position, as defined by SIG_STOP.
Notice that SIG_COUNTER will increment while this takes place. (Typically approximately 670
data sets will be collected with the above settings and full stroke of the valve. Exact numbers will
vary.)
14. SIG_FLAGS indicates SIG COMPLETE.
15. Return the MODE_BLK to auto.
16. Notify control room the valve is back on-line. The stored signature will remain in the Logix
3400IQ digital positioner RAM until the either the unit is powered down, or another signature is
taken which overwrites the previous one.
7.16 Step Signature
If a step signature was desired, simply do not select STEP_RAMP in SIG_FLAGS, and then set the
STEP_TIME prior to selecting BEGIN_SIG.
7.16.1 Collection of Stored Signature
The collection of the stored signature is accomplished by the host system. It is not part of the device.
See host system programming. A simple utility using National Instruments NI-FBUS is available from
Flowserve for retrieving a signature file.
The retrieved file is stored in a text format that can be imported into other programs for plotting and
analysis. Contact Flowserve for more details.
7.17 Glossary
A/D Also called ADC. Analog-to-digital converter. An A/D converts an analog signal into an integer
count. This integer count is then used by the microcontroller to process sensor information such as
position, pressure, and temperature.
D/A Also called DAC. Digital-to-analog converter. A D/A converts an integer count into an analog
output signal. The D/A is used to take a number from the microcontroller and command an external
device such as a pressure modulator.