Ma Control; Ma Output; Verifying The Ma Range - Siemens SITRANS LUT400 Operating Instructions Manual

mA Control

mA output

The SITRANS LUT400 has one mA output, used for communications with other devices.
Example:
Configuring the mA output to send a 4 to 20 mA signal corresponding to a scaled value of
10% to 90% of maximum process level on a 60 m transducer:
Parameter
2.5. 1 . Current Output
Function 2.5.2. Cur-
or
rent Output Function
2.5.3. 4 mA Setpoint
2.5.4. 20 mA Setpoint
2.5.5. Minimum mA
Limit
2.5.6. Maximum mA
Limit
a.
If the level reading drops below 6 m, the mA output drops below 4 mA.
b.
If the level reading rises above 54 m, the mA output rises above 20 mA.
Note: If default values (4 and 20 mA) are used for the minimum and maximum mA
limits, the mA output (shown in
mA limit, even if the level reading falls below/rises above the mA setpoints.

Verifying the mA range

Checks that the external device can track the entire 4 to 20 mA range sent by the SITRANS
LUT400. Follow the steps below if actual mA readings differ between the LUT400 (shown in
2.5.8. Current Output Value
1. To test the loop current, set
value to use in
2. Check that the external device displays the same mA reading as the mA value set
above.
3. If external device reading differs from the set manual value on the LUT400, adjust
the reading on the external device to match the reading on the LUT400.
Page 72 SITRANS LUT400 (HART) – OPERATING INSTRUCTIONS
Sample
Description
Value
LEVEL send mA proportional to level reading
6 set 4 mA at process level equal to 10% of maximum
(Low Cal minus High Cal)
54 set 20 mA at process level equal to 90% of maxi-
mum (Low Cal minus High Cal)
3.5 set minimum mA level below 4 mA
22.8 set maximum mA level above 20 mA
2.5.8. Current Output Value
) and an external device (such as a PLC).
2.5.1. Current Output Function
2.5.7. Manual Value
.
a
b
) will remain at the set
to Manual, then set the
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