IN19856
- 23 -
Rev 2
18.2.
Counts as Feedback
A 16-bit value is received from the ITV. The upper 4 bits are 0. The lower 12 bits represent the
count value. The count value indicates the current pressure output of the ITV. The inverse of the
setpoint scaling factor is used to determine the feedback in the unit type selected. The count value
can be converted to pressure units using the following formulas:
“Maximum Pressure Scaling Formula” (using
ITV Scale Factors):
𝑭𝒆𝒆𝒅𝒃𝒂𝒄𝒌 𝑷𝒓𝒆𝒔𝒔𝒖𝒓𝒆 = (
𝒄𝒐𝒖𝒏𝒕𝒔 × 𝒎𝒂𝒙𝒊𝒎𝒖𝒎 𝒑𝒓𝒆𝒔𝒔𝒖𝒓𝒆
𝟒𝟎𝟗𝟓
)
“Scale Factor Table Formula” (
using ITV Scale Factors):
𝑭𝒆𝒆𝒅𝒃𝒂𝒄𝒌 𝑷𝒓𝒆𝒔𝒔𝒖𝒓𝒆 =
𝒄𝒐𝒖𝒏𝒕𝒔
𝒔𝒄𝒂𝒍𝒆 𝒇𝒂𝒄𝒕𝒐𝒓
18.3.
Using engineering units
Engineering units can be selected from either the webpage or explicit messaging. Below is how to
set the ITV to engineering unit mode using the webpage. Refer to Explicit Messaging to config from
the PLC. Note: Changing to and from engineering mode should be done without a setpoint
command.
1.
Select Engineering Unit Mode from the Device Control and Status web page
2.
Select the engineering unit desired by selecting the radio button corresponding to the desired
unit type.
3.
Check Engineering Unit Check Box
4.
Click Submit
–
Changes will be made immediatelyThe selected engineering unit will be stored in
internal memory and will be retained permanently, even if power is cycled, until a different unit
is selected using procedure 1-3 above.
0
819
1638
2457
3276
4095
4914
0
1000
2000
3000
4000
5000
6000
0.00
0.10
0.20
0.30
0.40
0.50
0.60
Count
s
(16
-b
it
N
umb
er
)
Pressure (MPa)
ITV#030 COUNT SCALING
