Emerson Rosemount X-Stream Series, Инструкция по эксплуатации

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Emerson Process Management GmbH & Co. OHG
5-21
X-STREAM XE
Instruction Manual
HASXEE-IM-HS
10/2012
5
Startup
5.7 Checking the Settings
Tab. 5-1: Analog Output Signals Settings and Operation Modes
Operational modes conforming to NAMUR 43
recommendations (NE 43)
data acquisition system is enabled to distinguish
between the following situations
:
•
valid measured value (signal within range
as per table 5-1)
•
signal out of range (signal slowly rises or
falls towards the limits given in table 5-1,
and holds that value until the concentration
returns to within the measuring range).
• failure (signal out of range as per table 5-1,
but not 0)
• severed cable (no signal [0 mA]),
Table 5-1 provides a summary of all available
operational modes.
Output signal, if
"OutRange" "FailMode"
Failure
signal level
acc. NE 43
Measured
value is
valid
Measured value is
below lower limit
("Low scale")
Measured value is
above upper limit
("High scale")
An internal
failure
occured
Cable is
severed
0-20 mA Track -
0…20 mA
< -19 mA
> 21.7 mA undefined
0 mA
4-20 mA Track -
4…20 mA
< -19 mA
> 21.7 mA undefined
0 mA
0-20 mA
LOW - 10 % below 0…20 mA
-0.20 mA*
(-1.80…-0.01 mA)**
20.50 mA*
(20.01…21.50 mA)**
-2 mA 0 mA
4-20 mA
LOW - 10 % below 4…20 mA
3.80 mA*
(2.20…3.99 mA)**
20.50 mA*
(20.01…21.50 mA)**
2 mA 0 mA
0-20 mA HIGH + 10 %
above 0…20 mA
-0.20 mA*
(-1.80…-0.01 mA)**
20.50 mA*
(20.01…21.50 mA)**
> 21.7 mA
0 mA
4-20 mA HIGH + 10 %
above 4…20 mA
3.80 mA*
(2.20…3.99 mA)**
20.50 mA*
(20.01…21.50 mA)**
> 21.7 mA
0 mA
Note!
The application of values marked * or ** depends on the setting of "Cut Mode"
(
Analog outputs setup menu, page 6-67)
.
The common modes for analog outputs do
not support the detection of a failure in the
measurement system. In such a case, the
behaviour of the output signal is undefined:
either the last value is held, or a random value
is sent. System failures cannot be detected
by an external data capture system.
NE43 includes recommendations for such
cases, but also for the configuration of analog
outputs to detect other measurement states.
X-STREAM analyzers incorporate these re-
commendations as follows:
Setting " FailMode " to HIGH + 10% or LOW -
10%
defines specific analog output signals in
case of a failure. Since these values are not
output under normal operation conditions, a