Siemens SITRANS P DS III - Page 204

Technical data
13.4 Measuring accuracy
SITRANS P DS III with PROFIBUS PA
204 Operating Instructions, 06/2013, A5E00053276-07
Differential pressure and flow rate measuring accuracy
HART
PROFIBUS PA and FOUNDATION
Fieldbus
Reference conditions
• Rising characteristic curve
• Start of scale 0 bar
• Seal diaphragm stainless steel
• Measuring cell with silicone oil filling
• Room temperature 25 °C (77 °F)
• Measuring span ratio r
r = max. measuring span/set
measuring span
–
Measurement deviation with limit
setting, including hysteresis and
repeatability
Linear characteristic curve
≤ 0.075
• r ≤ 10
≤ (0.0029 • r + 0.071) % –
• 10 < r ≤ 30
≤ (0.0045 • r + 0.071) % –
• 30 < r ≤ 100
≤ (0.005 • r + 0.05) % –
Square root extracting characteristic
curve (flow rate > 50%)
≤ 0.1%
• r ≤ 10
≤ 0.1% –
• 10 < r ≤ 30
≤ 0.2% –
square root extracting characteristic
curve (flow rate 25 … 50%)
≤ 0.2%
• r ≤ 10
≤ 0.2% –
• 10 < r ≤ 30
≤ 0.4% –
Settling time T
63
without electrical
damping
• Approx. 0.2 s
• approx 0.3 s for measuring cell 20 and 60 mbar (0.29 and 0.87 psi)
Long-term drift at ±30 °C (±54 °F) ≤ (0.25 • r) % per five years
static pressure max. 70 bar g
(1015 psi g)
≤ 0.25 % per five years
static pressure max. 70 bar g
(1015 psi g)
• 20 mbar (0.29 psi) measuring cell
≤ (0.2 • r) % per year ≤ 0.2 % per year
• 250, 600, 1600 and 5000 mbar
(0.29, 0.87, 2.32 and 7.25 psi)
measuring cell
≤ (0.125 • r) % every 5 years ≤ 0.125% every 5 years
Effect of the ambient temperature
(double values for measuring cell
20 mbar g (0.29 psi g))
As percentage
• At -10 … +60°C (14 … 140°F)
≤ (0.08 • r + 0.1) % ≤ 0.3%