Yokogawa 415 Steam and Gas - Manual (Page 22)

PROGRAMMING THE SPAN AS MASS
It is also possible to enter the span of an analog flowmeter in mass
(instead of volume) at a nominal flowrate. The flow computer will
then automatically calculate the Span, S
VB
, for corrected volume flow
as:
......(9) S
VB
=
S
M
ρ
B
Example 2
If a flowmeter produces 1000 kg/h at 30°C and 220 kPa, and the
specific gravity is 1.52 then from equation (2)
ρ
=
3.4834 x 1.52 x 220
1 x
(
30 + 273.2
)
(assuming Z
B
= 1) = 3.84 kg/m 3
Therefore, from equation (9)
S
VB
=
1000
3.84
If the span is programmed as mass S
M
= 1000 kg/hr, with the base
temperature programmed to 30°C and the base pressure
programmed to 220 kPa, then the flow computer will display both
mass (kg/hr) and volume (m
3
/hr) corrected to a base condition of
30°C and 220 kPa.
20 Operation
= 260 m 3 /hr