Honeywell STT850 Series, Руководство пользователя

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Page 78 STT
850 Series HART/DE Option User’s Manual
Revision 4.0
7.2 Analog Output Signal Calibration
With a Transmitter in its constant current source mode, its analog output circuit can be calibrated at
0 (zero) % and 100% levels. It is not necessary to remove the Transmitter from service.
The following procedure is used for analog output signal calibration. You can calculate milliamperes
of current from a voltage measurement as follows: Dc milliamps = 1000 X voltage/resistance
IMPORTANT: Be sure that the accuracy of the resistor is 0.01% or better for current
measurements made by voltage drop
.
1.
Check that the Write Protect Jumper is in the “OFF” position.
2. Connect the MC Toolkit across loop wiring, and turn it on. See Figure 6 for a sample test
equipment hookup.
3. Launch the FDC application.
4. On the Home page, select Online and establish a connection with the device as follows
5. Check that the device is not in the Write Protect mode.
6. Select the My Device menu, and choose from the following menus:
a. Device setup \ Calibration \ Calibration Methods \ D/A trim
7. You will be prompted to remove the loop from automatic control; after removing the loop
from automatic control, press OK.
8. When a prompt appears, connect a precision milliammeter or voltmeter (0.03% accuracy or
better) in the loop to check readings, and press OK. The following prompts will be displayed:

Setting field device to output to 4mA. Press OK

Enter meter value. Key in the meter value, and press ENTER.

Field device output 4.000 mA equal to reference meter?
1 Yes, 2 No
-
If the reference meter is not equal to the field device output then select No and
press Enter
-
Key in the new meter value
-
Return back to the “Enter Meter Value” prompt until the field device output
equals the reference meter
-
Select Yes and press Enter
9. The following display prompts will appear:

Setting field device output to 20mA. Press OK

Enter meter value. Key in the meter value, and press ENTER.

Field device output 20.000 mA equal to reference meter?
1 Yes, 2 No
-
If the reference meter is not equal to the field device output then select No and
press Enter
-
Key in the new meter value
-
Return back to the ”Enter Meter Value” prompt until the field device output
equals the reference meter
-
Select Yes and press Enter
10. The prompt notifies you that the field device will be returned to its original output