Setting/Adjusting Start Of Scale/Full Scale - Siemens SITRANS P 7MF4013 Instruction Manual

3.1.2

Setting/Adjusting Start of Scale/Full Scale

The start of scale and full scale can be set or adjusted using the pushbuttons. A rising
or falling characteristic can be implemented in this way.
3.1.2.1 Relationships
A desired start of scale and/or a desired full scale are assigned to the standard cur-
rent values (4 mA/20 mA) when setting. Condition: Two reference pressures (p
provided by the process or generated by a pressure transmitter. The measuring span
specified on the measuring point plate no longer matches the adjustment after set-
ting.
A turn-down up to 1:30 can be achieved.
NOTE
The measuring span is not altered by setting the start of scale. The start of scale
remains unchanged when the start of scale is set.
The relationship between the measured pressure and the generated output current
is linear. The output current can be calculated using the following equation (Figure 8,
p. 83).
I = output current in mA
P = applied pressure
ME = full scale
MA = start of scale
ME - MA = MS (measuring span)
Figure 8
NOTE
If the transmitter is operated locally, write accesses through HART® are denied
during this time. Data, e.g. measured values, can be read at any time.
SITRANS P, MS series
C79000-B5674-C40-04
Formula for calculating the current
On-site Operation and Display
P - MA
I = * 16 mA + 4 mA
ME - MA
, p )
r1 r2
83