Filter
Top Products
Emerson Process Management GmbH & Co. OHG 5-21
X-STREAM X2
Instruction Manual
HASX2E-IM-HS
02/2012
5
Startup
5.7 Checking the Settings
Operational modes conforming to NAMUR
43 recommendations (NE 43)
The modes described so far do not generate
any signal which would allow the detection of
a failure in the measurement system. In such
a case, the behaviour of the output signal is
undened: either the last value is held, or a
random value is sent. System failures cannot
then be detected by an external data capture
system.
NE43 includes recommendations for such
cases, but also for the conguration of analog
outputs to detect other measurement states.
X-STREAM analyzers incorporate these re-
commendations as follows:
Setting the “SignalRange” parameter to a
value other than 0-20 mA or 4-20 mA de-
nes specic analog output signal levels for
system failures. Since these values are not
sent during normal operation, a data capture
system is able 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 shows an overview of all available
operational modes.
Tab. 5-1: Analog Output Signals: Settings and Operational Modes
Output signal, if
"Signal-
Range“
Operation Mode
Failure
Signal Level
acc. NE 43
Measured
value is
valid
Measured value is
below lower range
limit
Measured value is
above upper range
limit
An internal
failure
occured
Cable is
broken
0-20 mA Dead-Zero - 0 ... 20 mA < -19 mA > 21.7 mA undened 0 mA
4-20 mA Live-Zero - 4 ... 20 mA < -19 mA > 21.7 mA undened 0 mA
0-20 mAL
similar Dead-
Zero
below 0 ... 20 mA
-0.2 mA*
(-1.8 … -0.01 mA)**
20.5 mA*
(20.01 ... 21.5 mA)**
-2 mA 0 mA
4-20 mAL similar Live-Zero below 4 ... 20 mA
3.8 mA*
(2.2 ...3.9 mA)**
20.5 mA*
(20.01 ... 21.5 mA)**
2 mA 0 mA
0-20 mAH
similar Dead-
Zero
above 0 ... 20 mA
-0.2 mA*
(-1.8 … -0.01 mA)**
20.5 mA*
(20.01 ... 21.5 mA)**
> 21.7 mA 0 mA
4-20 mAH similar Live-Zero above 4 ... 20 mA
3.8 mA*
(2.2 ...3.9 mA)**
20.5 mA*
(20.01 ... 21.5 mA)**
> 21.7 mA 0 mA
Note!
The application of values marked * or ** depends on the setting of "SignalRange"
( Analog outputs menu, page 6-31).