National Instruments FP-3000 - Manual (Page 47)

Chapter 3 Example Applications
FieldPoint FP-3000 User Manual 3-12 www.ni.com
Scale the Output
1. You can avoid setting the XD_SCALE value manually if you set the
CFG_OPTS option on the Options tab to Automatically adjust
XD_SCALE . This allows the FP-3000 to copy the value from
FP_AO_200_RANGE straight into the XD_SCALE parameter. Otherwise,
tell the block the range of values to output to the transducer module.
Go to the
XD_SCALE parameter on the Scaling tab and enter the
following:
XD_SCALE
EU_100 0.021
EU_0 0
Units_Index A
Decimal 2
This tells the AO block to output readings in the range of 0 to 0.021 A
(0-21 mA) to the FP-AO-200 module.
2. Determine the Process Variable (PV) scale. This scaling parameter is
used to convert from the units of Set Point (SP) to percent of scale. For
output function blocks like analog output, SP is the value you want the
block to output. For this example, set
PV_SCALE to 0 to 100 percent.
With these settings, a controller or operator changing the setpoint of
this AO block writes the percentage of scale, with 100% being
maximum output current.
PV_SCALE
EU at 100% 100
EU at 0% 0
Units Index %
Decimal 2
In the case of Analog Output blocks, you do not need to explicitly set the
type of scaling. The block will always use both
XD_SCALE and PV_SCALE
parameters linearly.
Bring the Block Online
1. Go to the MODE_BLK parameter on the Process tab and set the TARGET
to Auto , or click on the Auto button on the block configuration
window.
2. If the Periodic Updates checkbox is checked, the MODE_BLK.ACTUAL
parameter should change to Auto after a few seconds. Otherwise,
re-read the parameter by clicking on the Read Selected or Read All
button with
MODE_BLK selected. If it does not go to Auto , refer to
Appendix F, Troubleshooting , for more information.