Page 88
STT700 Series HART/DE Option User’s Manual
Revision 1
7.3 Calibrating Analog Inputs
The STT700 SmartLine Temperature Transmitter supports two-point input calibration. This result of
this calibration is that when two points in a range are calibrated, all points in that range adjust to the
calibration.
Calibration High and Low points should always be calibrated both at the same time.
This procedure assumes that the transmitter has been removed from the process and is located in a
controlled environment.
IMPORTANT! You must have a precision calibrator source with an accuracy of 0.02% or
better to do an input calibration. Note that the factory calibrates STT700 SmartLine
Temperature Transmitters temperature in deg C.
7.3.1 Correcting the Low Calibration Point
1.
Figure 7 shows typical test connections. As shown, connect the power supply and
communicator to the signal terminals of the transmitter terminal block.
2.
Connect the precision calibrator source to the sensor (to be corrected) inputs of the transmitter.
3.
Turn on the power supply, and allow the transmitter to become stable.
4.
Turn the MC Toolkit on, start the FDC application.
5.
On the FDC Home page, select Online, and establish communication with the transmitter.
6.
Check that the device is not in the Write Protect mode.
7.
The Lower Calibration Point and Upper Calibration Point values must be entered in the
respective sensor config parameters in the Sensors menu. These calibration points are used in
the S 1 / 2 Cal Lo Correct and S 1 / 2 Cal Hi Correct methods (not LRV and URV).
8.
Select the My Device menu, and choose from the following selections:
o
Device Setup \ Advanced Configuration\Calibration \ Calibration Methods \ Sensor (1
or 2) Cal Lo Correct
9.
You will be prompted to remove the loop from automatic control. After removing the loop
from automatic control, press OK.
10.
When prompted, adjust the temperature source to apply value equal to the Lower Calibration
Point, and press OK.
11.
When the temperature stabilizes, wait for 5 seconds, then press OK.
12.
When prompted, remove temperature.
13.
On the next prompt – “Please enter Calibration Date in MM/DD/YYYY format. Enter the
Calibration date (for example “05/27/2009”) and press Enter.
14.
On the next prompt - "Please enter the current calibration time in 24 Hr format (Hours Field)",
enter the Hours field HH (for example, "12"), and press ENTER
15.
On the next prompt – “Please enter current Calibration Time (Minute field),” enter the
Minutes field MM (for example “23”), and press ENTER.
16.
When prompted to return the loop to automatic control, press ENTER
NOTE:
If you are calibrating Calibration High and Low Points at the same time, do not power
down and start up again after the S 1 / 2 cal. Lo Point steps, just go to step 1 of the S 1 / 2 cal. Hi
Point procedure below.
