Current Transmitter Adjustment / Voltage Transmitter Adjustment - Siemens SITRANS TW 7NG3242 Betriebsanleitung

NOTE
− The sensor adjustment is reset automatically after every parameterization of the
sensor type.
− In the difference or average forming type of circuit (chapter 6.4, page 129) the
sensor adjustment can be made for measuring channel 1 and for measuring
channel 2.

4.2.13 Current transmitter adjustment / Voltage transmitter adjustment

The current output by the transmitter or the voltage output by the transmitter can be
adjusted independently of the process circuit. This function is suitable for compen-
sating inaccuracies in the operating sequence following the transmitter. The adjust-
ment is only possible at 0/4 ... 20 mA or at 0/2 ... 10 V. Figure 13, page 106 shows
the adjustment principle by an example of the 4 ... 20 mA current output.
Application example: Adjustment of the 4 ... 20 mA current output
The current should be measured as a voltage drop of 1 V to 5 V on a resistance of
250Ω ± 5 %. To compensate the tolerance of the resistance, set the current trans-
mitter so that the voltage drop at 4mA is exactly 1V and at 20mA exactly 5 V.
ATTENTION
A multimeter which is used must have a higher class accuracy than the
transmitter.
1. Adjustment at 4 mA:
Under menu item D/A adjustment you instruct the transmitter to output 4mA. You
read the measured value on the voltmeter, calculate the current value from it and
enter this, for example, via the SIMATIC PDM. The transmitter uses this value for
current offset correction.
2. Adjustment at 20 mA:
Under menu item D/A adjustment you instruct the transmitter to output 20mA. You
read the measured value on the voltmeter, calculate the current value from it and
enter this, for example, via the SIMATIC PDM. The transmitter uses this value for
current slope correction. The value for 4 mA is not changed.
SITRANS TW
A5E00054075-05
Functions / Operation by HART
105