Siemens Sitrans 사용자 설명서
Page 32
SITRANS LC 500 – INSTRUCTION MANUAL
7ML19985GE01
mmmmm
Int
er
connect
ion
Communications
The SITRANS LC 500 is equipped
with HART
communication
1
protocol
2
so that settings
and values can be obtained and altered locally
3
or remotely.
Typical PLC configuration with HART
Diagnostics
The internal diagnostic functions continuously monitor the operation of the transmitter.
An error signal is generated if a failure or irregularity occurs.
An error signal is generated if a failure or irregularity occurs.
The SITRANS LC 500 sends the signal current according to the NAMUR NE 43
recommendation. During normal operation the current remains within the range from 3.8
to 20.5 mA. If the process exceeds its normal limits but is not in a fault or failure situation,
the signal current will be outside the measurement range (4 to 20 mA) but will be limited
to either 3.8 or 20.5 mA.
recommendation. During normal operation the current remains within the range from 3.8
to 20.5 mA. If the process exceeds its normal limits but is not in a fault or failure situation,
the signal current will be outside the measurement range (4 to 20 mA) but will be limited
to either 3.8 or 20.5 mA.
If a fault or a failure is detected, the signal current is set to either 3.6 mA or 22 mA,
depending on the settings you have chosen. (This feature may be disabled by the user.)
depending on the settings you have chosen. (This feature may be disabled by the user.)
1.
Depending on the system design, the power supply may be separate from the
PLC, or it may be part of the PLC.
PLC, or it may be part of the PLC.
2.
A 250 Ohm resistor is required only when the PLC is connected to a HART
modem or a HART communicator.
modem or a HART communicator.
3.
The HART communicator and a PCL/laptop computer cannot both be connected
to the 4-20 mA loop simultaneously.
to the 4-20 mA loop simultaneously.
power supply
1
R
2
= 250
Ω
SITRANS LC 500
PC/laptop with Simatic PDM or HART communicator
3