DRAFT - 20 November 2014
DRAFT - 20 November 2014
4
INM 660 rev 14
2 - SENSORS
21 SIGNAL
The MTL661/2/3/5 can process the 4-20mA signal in two ways:
1) Interpolation: the signal is processed linearly
D = S x I
2) Square root: for differential pressure
D = S
√
I
where:
D =
Value:
the displayed value
S = Span:
the maximum value at 20mA. The span is
programmed with setting 15.
I =
Input:
the scaled analogue value; in these formulas
value 0 (zero) for 4mA and value 1 (one) for
20mA.
22 FILTER
The output signal from the field sensor is measured several times
a second. The value measured is therefore a “snap-shot” of the
signal and may fluctuate rapidly. This digital filter enables a more
stable and accurate reading to be obtained through the choice of a
suitable filtering value.
The effect of the filter is based on three variables: the
filter value (01-99), the last measured analogue value and
the last average value. The higher the filter value, the
slower the response to an input change will be. Several
filter values and their response times effects are indicated
below:
Filter value
Response time on step change of analog value
Time in seconds
50% effect
75% effect
90% effect
99% effect
01
filter disabled
filter
disabled
filter
disabled
filter
disabled
02
0.3 seconds
0.5 seconds
1.0 seconds
1.8 seconds
03
0.5 seconds
1.0 seconds
1.5 seconds
3 seconds
05
1.0 seconds
1.8 seconds
2.8 seconds
5.3 seconds
10
1.8 seconds
3.5 seconds
5.6 seconds
11 seconds
20
3.5 seconds
7.0 seconds
11 seconds
23 seconds
30
5.3 seconds
10 seconds
17 seconds
34 seconds
50
8.8 seconds
17 seconds
29 seconds
57 seconds
75
13 seconds
26 seconds
43 seconds
86 seconds
99
17 seconds
34 seconds
57 seconds
114 seconds
23 TUNE MIN / 4MA
Be very sure that the offered signal is correct before the
calibration is executed as this function has a major
influence on the accuracy of the system!
This setting enables the user to calibrate a specific input
value as the 4mA point, because the signal from the sensor might
not be exact 4.0 mA at zero span. This adjusts the actual input
value at zero.
After pressing PROG, three settings can be selected:
CALIBRATE – With this setting, the input will be calibrated with
the actual “4mA” value. After pressing ENTER, CAL SET will be
displayed as soon as the indicator completes its calibration. From
that moment, the analogue input value must be more than the
calibrated value before the signal will be processed.
DEFAULT – This resets the calibration to the manufacturer’s factory
setting.
CAL SET – This selects the value last used for calibration.
24 TUNE MAX / 20MA
This setting enables the user to calibrate a specific input value as
the 20 mA point, because the signal from the sensor might not be
exact 20.0 mA at the maximum span. This establishes the actual
input value at full range.
After pressing PROG, three settings can be selected:
CALIBRATE: with this setting, the input will be calibrated with
the actual “20mA” value. After pressing enter, CAL SET will be
displayed as soon as the calibration is completed. From that
moment, the analogue value must be less than the calibrated
value for a reliable measurement.
DEFAULT: with this setting, the manufactures value is re-installed.
CAL SET: to select the last calibrated value.
3 - OTHERS
31 TYPE OF MODEL
For support and maintenance it is important to have information
about the characteristics of the MTL661/2/3/5.
Your supplier will ask for this information in the case of a serious
breakdown or to assess the suitability of your model for upgrade
considerations.
32 VERSION SOFTWARE
For support and maintenance it is important to have information
about the characteristics of the MTL661/2/3/5.
Your supplier will ask for this information in the case of a serious
breakdown or to assess the suitability of your model for upgrade
considerations.
33 SERIAL NUMBER
For support and maintenance it is important to have information
about the characteristics of the MTL661/2/3/5.
Your supplier will ask for this information in the case of a serious
breakdown or to assess the suitability of your model for upgrade
considerations.
34 PASS CODE
All SETUP-values can be pass code protected.
This protection is disabled with value 0000 (zero).
Up to and including 4 digits can be programmed, for example
1234.
35 TAGNUMBER
For identification of the unit, a unique tag number of maximum 7
digits can be entered.
NOTE
