Ma Control; Ma Output - Siemens SITRANS LUT400 Operating Instructions Manual

General Operation

7.4 mA Control

This logic can also be reversed (NORMALLY OPEN to NORMALLY CLOSED or vice versa).
Use the Discrete Input logic parameters to set the state of each discrete input.
Function
Discrete Inputs (2.9.)
(Page 207)
Read the current state of discrete input 1 in Discrete Input 1 Scaled State (2.9.2.2)
(Page 209) and the current state of discrete input 2 in Discrete Input 2 Scaled State (2.9.2.4)
(Page 209).
See Discrete inputs (Page 45) for complete details on wiring the discrete inputs. To override
a level using a discrete input, see Backup Level Override (2.9.1) (Page 208).
7.4 mA Control
7.4.1

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
Current Output Function (2.5.1.)
(Page 176) or Current Output
Function (2.5.2.) (Page 176)
4 mA Setpoint (2.5.3.)
(Page 178)
20 mA Setpoint (2.5.4.)
(Page 178)
Minimum mA Limit (2.5.5.)
(Page 178)
Maximum mA Limit (2.5.6.)
(Page 179)
If the level reading drops below 6 m, the mA output drops below 4 mA.
1)
If the level reading rises above 54 m, the mA output rises above 20 mA.
2)
94
Discrete Input Logic (2.9.2)
(Page 208)
Sample Value
LEVEL
6
54
3.5
22.8
Parameter
Discrete Input 1 Logic (2.9.2.1)
(Page 209)
Discrete Input 2 Logic (2.9.2.3)
(Page 209)
Description
send mA proportional to level reading
set 4 mA at process level equal to 10% of max-
imum (Low Cal minus High Cal)
set 20 mA at process level equal to 90% of
maximum (Low Cal minus High Cal)
set minimum mA level below 4 mA
set maximum mA level above 20 mA
Operating Instructions, 07/2019, A5E33329501-AC
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SITRANS LUT400