ABB Platinum standard Series Product Instruction page 61

CALIBRATION
CALIBRATION PROCEDURES
4 - 4
four to 20-milliampere current loop has changed. To adjust
the zero of the transmitter, refer to
Either connect the DMM, set to measure DC milliamperes, in
series with the four to 20-milliampere current loop, or make a
parallel connection across the precision 250-ohm resistor
shown in Figure 2-4, with the DMM set to measure VDC. With
the latter setup, the four to 20-milliampere output corre-
sponds to one to five VDC.
NOTES:
1. These notes only apply when measuring VDC across the
250-ohm resistor shown in Figure 2-4.
2. The loop resistor must have a tolerance of 0.01 percent or bet-
ter in order for this procedure to be valid.
3. If a resistor value other than a 250 ohms is used, the voltage
output will be different according to Ohms law:
( × )
V I R
=
4. Throughout this procedure, the voltage values, based on a
250-ohm resistor, will be shown in parentheses following the milliam-
pere values.
1. Press the CALIBRATE key on the Type STT terminal.
2. Use the up arrow and down arrow keys to scroll through
the menu and select D-A ADJUSTMENT.
3. Press the ENTER key.
4. The instruction, ADJUST TO 4 mA THEN HIT ENTER
appears on the display. Use the up arrow and down arrow keys
to adjust the output to 4.000 mA (1.000 VDC) plus or minus
the tolerance for the particular transmitter listed in Table 4-1.
If using a receiving device (e.g. recorder), adjust for a
zero-percent indication.
5. Press the ENTER key.
6. The message, ADJUST TO 20 mA THEN HIT ENTER appears
on the display. Use the up arrow and down arrow keys to
adjust the output to 20.000 mA (5.000 VDC) plus or minus the
tolerance for the particular transmitter listed in Table 4-1. If
using a receiving device, adjust for a 100-percent indication.
7. Press the ENTER key.
REZERO PROCEDURE.
WBPEEUI110504A0