Analog Output Signal Calibration - Honeywell ST 700 User Manual

8.2 Analog Output Signal Calibration

With a Transmitter in its constant current source mode, its analog output circuit can be calibrated at
its 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
1. Connect the MC Toolkit across loop wiring, and turn it on.
2. Launch the FDC application.
3. On the homepage, click Online and establish a connection with the device as follows;
4. Click the My Device menu, and choose from the following menus:
a. Device setup \ Calibration \ Calibration Methods \ D/A trim
5. You will be prompted to remove the loop from automatic control; after removing the loop
from automatic control, press OK.
6. When a prompt appears, connect a precision millimeter 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 4.000mA equal to reference meter?
1 Yes
2 No
a. If the reference meter is not equal to the field device output then click No and
b. Return to the Enter Meter Value prompt until the field device output equals
c. Click Yes and press Enter
7. 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
a. If the reference meter is not equal to the field device output then click No and
b. Key in the new meter value.
c. Return to the Enter Meter Value prompt until the field device output equals
d. Click Yes and press Enter.
8. The prompt notifies you that the field device will be returned to its original output
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press the Enter Key in the new meter value.
the reference meter
press Enter.
the reference meter.
ST 700 Series HART/DE Option User's Manual
Revision 4.0