IN19856
- 21 -
Rev 2
17.
Pressure In-range Window Diagnostic
This diagnostic will monitor the pressure feedback and determine if it is outside of a window
pressure range for a specified elapsed time. If it is, then an error flag is set called Window Error,
else the Window Error flag is cleared as the pressure is within the in-range pressure window. This
is a useful feature to test if you achieved or are maintaining the setpoint.
17.1.
Configuring the in-range window
In-range diagnostic is an always enabled feature. The defaults are already set at the factory and
only need to be changed if a different response is desired. The in-range window is configured by
adjusting the User Gain and User Sensitivity values on the Device Control & Status web page (also
via explicit messaging). Note: Changing the Gain and Sensitivity will also change the responsiveness
of the ITV.
For User Gain: Default is 8 which is a timeout of about 5 seconds
User Gain = 0 is a 10 second timeout.
User Gain = 15 is a 1 second timeout.
The timeout time is linear between the User Gain values of 0 to 15.
For User Sensitivity: Default is 2 which is about 2%
User Sensitivity = 0 is 1% of full scale.
User Sensitivity = 7 is 5% of full scale.
The percentages are linear between the User Sensitivity values of 0 to 7.
18.
Setpoint and Feedback
Setpoint is the requested value for the ITV’s regulated pressure or vacuum output. An external
master (typically a PLC) sends the setpoint value to the ITV, either in counts or engineering units.
Counts is the default of the ITV. The full-scale pressure range of the ITV is scaled across 12bit (0-
4095). Example: Mid pressure for an ITV would be 2048. During machine start up or
troubleshooting, the ITV web page can be used to enter a setpoint values.
This version of the ITV supports not only counts but also various types of engineering units as
pressure set point and pressure feedback values. This ITV supports Counts, kg/cm^2, BAR, PSI, kPa
and, MPa as acceptable pressure set point units. Caution - Changing unit type should be done when
setpoint is zero as current setpoint will be interpreted as the new unit type. This could cause the
pressure to go to max pressure.
18.1.
Counts as Setpoint
Counts can be used to control the ITV pressure. The master device sends counts to the ITV for the
desired pressure. The ITV will then report the current pressure feedback value to the master
device in counts. The count range is 0 to 4095 (12 bits). The count range is the same for all ITVs.
The maximum pressure or vacuum corresponds to 4095 counts. For example, an X010 ITV body
size has a pressure range from 0 to 0.1 MPa. The maximum pressure would correspond to 4095
counts.
