Page 48
ST 800 Series HART/DE Option User’s Manual
Revision 5.0
Setting PV URV, and LRV Range Values
ST 800 Transmitters are calibrated at the factory with ranges using inH
2
O at 39.2
o
F (4
o
C).
For a reverse range, enter the upper range value as the LRV and the lower range value as the
URV.
When setting the range using applied pressure, the URV changes automatically to
compensate for any changes in the LRV. When using the Tookit keyboard, the URV does not
change automatically. To use the applied pressure method and change both the LRV and
URV,
change the LRV first
.
The LRV and URV values can be entered with the Toolkit keypad or by applying the corresponding
pressure values directly to the Transmitter. Use the following procedure to key in the range values.
The procedure uses an example of 5 to 45 referenced to inH
2
O.
1.
Starting at the My Device menu, make the following menu selections:
Shortcuts > Device Setup > Basic Setup > Device Information > Range values
2.
Click
Edit
. The “Range value” screen will be displayed.
3.
Select
PV LRV
and click
Edit
. You will be warned that if you change the value of the
variable it will change the loop current, which may upset the control process.
4.
Click
Yes
to continue.
5.
Enter the desired PV LRV value. (for example: 5).
6.
Click
OK
. The Range Values menu will be displayed
7.
Choose
Pressure URV
.
8.
Add the desired URV setting value (for example: 45).
9.
Press
ENTER
.
10.
Select the
PV URV
, and click
Edit
. You will be warned that if you change the value of the
variable, it will change the loop current, which may upset the control process.
11.
Click
Yes
to continue.
12.
Click
Return
to go back to the
Basic Setup
menu.
13.
Click
Send
. The Send to Device screen will be displayed.
14.
Select the
Range values
check box,
15.
Click
Send
to download the change to Transmitter, or Click
Return
to continue making
changes.
Setting Range Values for Applied Pressure
When setting the range values using applied pressure, the URV changes automatically to
compensate for any changes in the LRV and to maintain the present span (URV – LRV).
When entering the LRV using the Tookit keypad, the URV does not change automatically.
If you use the applied pressure method, and need to change the LRV and URV,
change the
LRV first
. You can also use the local zero and span adjustments on the Transmitter to set the
LRV and URV values.
1.
Starting at the
My Device
menu, make the following menu selections:
Shortcuts > Device setup > Calibration > Calibration Methods > Apply values.
