94
Type of Event
Status to generate a ‘1’ in the log Status to generate a ‘0’ in the log
Relay output
Relay activated
Relay not activated
Interlock DI
In the Interlock state as defined in
the Interlock page
In the non-Interlock state as defined in
the Interlock page
Level Switch DI
In the Low Alarm state as defined
in the Level Switches page
In the Normal state as defined in the
Level Switches page
Generic DI –
Alarm selected
In the Alarm state as defined in the
Generic Inputs page
In the Normal state as defined in the
Generic Inputs page
Generic DI – No
Alarm selected
Switch closed
Switch open
A window will open to ask if you would like to open the file or save it to disk. Select the method
you would like to use. The file is .csv (comma separated variable) file that will open in a
spreadsheet such as Excel.
6.23 Relay (1 – 8) Output Menus – Intermittent (Proportional Blowdown Time)
Types
This page is used for boiler control where the conductivity is checked at intervals, and if found to
be above the set point, the relay is activated for a time that varies with the conductivity’s deviation
from the set point.
The following sequence occurs while sampling:
The relay activates to open the control valve, allowing a sample of the boiler water to flow past the
electrode. The valve remains open for the time programmed in Duration of Sample.
The relay deactivates, and closes the control valve. The sample is held in the pipe for the time
programmed in Hold Time.
At the end of the hold time, the controller reads the conductivity, and compares it to the set point
value.
If it is above the set point, the relay activates and opens the valve for the time calculated using the
Maximum Blowdown Time and Proportional Band.
The valve closes again and the sample is held again.
If the conductivity is still too high, the blowdown time is recalculated and the valve is opened for
that time.
This continues until the conductivity is below the set point.
The valve closes and will not reactivate until the Interval Time has expired.
You may also change the Relay Control Mode here. If you do, you will have to reselect the Input
Assignment as well.
This section assumes that the Relay Control Mode is set to Intermittent (Proportional Blowdown
Time). Other control mode types are described in other sections of the manual.
Relay Control Mode
Click on the arrow of the pull down menu and select the way that you want to control the relay.
See Section 6.2 for details on each control mode.
Relay Input Assignment
Click on the arrow of the pull down menu to select the sensor to be used to activate this relay.
