57
9 Supplement
WIKA Operating Instructions - Process pressure transmitter IPT-2x
The additional factor FTD through Turn down is calculated according to the following formula:
F
TD
= 0.5 x TD + 0.5
In the table, example values for typical Turn downs are listed.
Turn Down
TD 1 : 1
TD 2.5 : 1
TD 5 : 1
TD 10 : 1
TD 20 : 1
Factor FTD
1
1.75
3
5.5
10.5
Ceramic/metal measuring cell
(
-12
F
TBasis
Fig. 28: Basic temperature error F
TBasis
at TD 1 : 1
The basic temperature error in % from the above graphic can increase due to the additional factors
depending on the accuracy class (factor FMZ) and Turn Down (factor FTD). The additional factors
are listed in the following tables.
Additional factor through accuracy class
Accuracy class
Measuring cell - Standard
0.075 %, 0.1 %
0.2 %
Factor FMZ
1
3
Additional factor through Turn Down
The additional factor FTD through Turn down is calculated according to the following formula:
F
TD
= 0.5 x TD + 0.5
In the table, example values for typical Turn downs are listed.
Turn down
TD 1 : 1
TD 2.5 : 1
TD 5 : 1
TD 10 : 1
TD 20 : 1
Factor FTD
1
1.75
3
5.5
10.5
Thermal change current output through ambient temperature
Applies also to the
analogue
4 … 20 mA current output and refers to the set span.
