Siemens Sitrans 사용자 설명서

7ML19985GE01

SITRANS LC 500 – INSTRUCTION MANUAL

Page 33

Whenever the local situation allows, the zero adjustment and the full scale can be set 
using the push-button feature and the appropriate menu selection. In most cases it is 
possible to do a one point calibration

1

 by using the push-buttons to input the actual level 

in %.

The total isolation between the measurement circuit and the current- loop circuit 
provides immunity during the use of cathode protected measuring tanks. Connection to 
PLC equipment is possible without any difficulty.

• The Upper Range Value (URV) and Lower Range Value (LRV) should be within 

the USL to LSL range, but can be set anywhere within that range.

• An interruption of the measuring connection will be detected: a loose or 

interrupted connection results in up to 0.5 pF capacitance, which is below the 
adjusted LSL and thus signals a FAULT condition.

The solid-state output is a polarity independent switch output. The solid-state switch has 
two possible functions. 

• it can be activated/deactivated when the product level reaches the upper/  

lower threshold settings (set in menus 15 and 16)

• or it can be activated if a fault or failure is detected

2

 (set in menu 18) 

See page 93 for an illustration of a typical application using SITRANS LC 500 as a level 
indicator, with the solid-state output connected to a relay which activates a pump.

The solid-state switch has its own parameter set: menu items 13 to18, (see 

  on page 37, and 

 chart on 

In menu 0E and menu 0F, you set the Upper and Lower Range Values (URV and LRV) for 
relay operation. Within that range, the solid-state switch has independent settings for 

1.

See 

  on page 43.

2.

See 

  on page 15 for details of fault conditions.

Measurement value

Fault- mA Value (F)

F  = 1

Fault- mA Value (F)

F = 1

mA

F = 0

Current values for signal detection

0

3.6

3.8

4.0

20 22

20.5