Siemens LC 500 Manuale Utente
7ML19985GE01
SITRANS LC 500 – INSTRUCTION MANUAL
Page 33
m
mmmm
Int
erc
onnect
ion
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
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.
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.
adjusted LSL and thus signals a FAULT condition.
Applications for Solid-state Output
The solid-state output is a polarity independent switch output. The solid-state switch has
two possible functions.
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.
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
relay operation. Within that range, the solid-state switch has independent settings for
1.
on page 43.
2.
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
Current values used as signals from digital transmitters