Tab. 5-1: Analog Output Signals: Settings And Operational Modes - Emerson Rosemount Analytical X-STREAM X2 Series Instruction Manual

Instruction Manual
HASX2E-IM-HS
10/2012
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
undefined: 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 configuration 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 defi-
nes specific analog output signal levels for
system failures. Since these values are not
"Signal-
Operation Mode
Range"
0-20 mA Dead-Zero
4-20 mA Live-Zero
similar Dead-
0-20 mAL
Zero
4-20 mAL similar Live-Zero
similar Dead-
0-20 mAH
Zero
4-20 mAH similar Live-Zero
Note!
The application of values marked * or ** depends on the setting of "SignalRange"
(
Tab. 5-1: Analog Output Signals: Settings and Operational Modes
Emerson Process Management GmbH & Co. OHG
5.7 Checking the Settings
Failure Measured
Signal Level value is
acc. NE 43 valid
- 0 ... 20 mA
- 4 ... 20 mA
below 0 ... 20 mA
below 4 ... 20 mA
above 0 ... 20 mA
above 4 ... 20 mA
Analog outputs menu, page 6-31).
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.
Output signal, if
Measured value is Measured value is
below lower range above upper range
limit limit
< -19 mA > 21.7 mA
< -19 mA > 21.7 mA
-0.2 mA* 20.5 mA*
(-1.8 ... -0.01 mA)** (20.01 ... 21.5 mA)**
3.8 mA* 20.5 mA*
(2.2 ...3.9 mA)** (20.01 ... 21.5 mA)**
-0.2 mA* 20.5 mA*
(-1.8 ... -0.01 mA)** (20.01 ... 21.5 mA)**
3.8 mA* 20.5 mA*
(2.2 ...3.9 mA)** (20.01 ... 21.5 mA)**
X-STREAM X2
An internal
Cable is
failure
broken
occured
undefined 0 mA
undefined 0 mA
-2 mA 0 mA
2 mA 0 mA
> 21.7 mA 0 mA
> 21.7 mA 0 mA
5-21