Ex p control unit
Motor purge controller
Commissioning
Rev. 0
01-37A2-7D0003_Operating instructions_MPC_20210923_0_en.docx
Page 67 of 96
8.1.3.4
“Purge time” setting
The procedure described here for determining the purge time is based
on the principle of manual purge time calculation
Assumptions for determining the purge time:
- All relevant parameters are assumed values -
When using the APEX
mpc
or SILAS
mpc
, the purging pressure p3 is set by means
of the purging flow control.
Procedure
Connect the PC with the Ex p control unit and activate the programming
switch
Log into the WEB interface with the user level
Call up the menu “Purging parameters / Pressure parameters”
Pressure parameter p3 - Set purging pressure to 2000 Pa (20 mbar)
A pop-up window displaying the changed value opens;
Confirm
Pressure parameter p5 - Set maximum purging pressure to the highest
value which the pressurised equipment is permitted to reach during
purging, e.g. set 2000 Pa (20 mbar)
A pop-up window displaying the changed value opens;
Confirm
Deactivate programming switch
The Ex p control unit changes from programming mode to
control/monitoring mode.
Press the “F5” key on the PC to refresh the browser window.
The Start screen opens.
Set the desired p3 purging pressure (actual value) by slowly opening the
purging flow control. Make a note of the reached p3 purging pressure, e.g.
10 mbar.
Open the chapter “Purge air diagram" in the operating
instructions
Read out the corresponding flow rate Q from the diagram as a
function of the determined p3, e.g. 220 000 l/h
Using the formula
t [min] = ((V [l] x purging factor) / Q [l/h]) x 60
3.5 min = ((2567 l x 5 times purging) / 220 000 l/h) x 60
Activate programming switch
Log into the WEB interface with the user level
Call up the menu “Purging parameters / Pressure parameters”
Pressure parameter p3 - Set purging pressure to the determined value
Pop-up window with display of changed value opens; Confirm
Call up the menu “Purging parameters / Purging modes”
Set purging time to the calculated purging time
A pop-up window displaying the changed value opens;
Confirm
Deactivate the programming switch
