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Changing Characterization
STEP 1 - From the HART
®
communicator
“Online” menu, move to the “Demand Setup”
menu and select the “Dem Curve” parameter.
This is accomplished by using the up and down
arrow keys to select the appropriate item in each
menu and then moving forward by pressing the
right arrow key. Follow the Menu Tree (Figure 1,
page 34) to navigate.
STEP 2 - With the “Dem Curve” parameter
selected, press the right arrow key to display
the four entry choices: “Linear”, "Square Root",
"Dem Curve Special" or “Square”. Use the
up and down arrow keys to select the desired
parameter.
STEP 3 - With desired choice selected,
push the F4 function key which is defined as the
ENTER key at the bottom of the display. Pushing
this key enters the selected parameter and
reverts the display back to the “Demand Setup”
main menu. If "Dem Curve Special" is selected,
proceed to the "Dem Curve Special" sub-menu to
setup the desired curve.
STEP 4 - At the bottom of the “Demand Setup”
menu, the F2 function key should now be defined
as the SEND key. Push this key to execute the
change.
WARNING
Carefully follow the on-screen warnings
and messages when proceeding, because
changing this parameter online will cause the
drive to reposition. This can adversely affect
the process and cause potentially dangerous
conditions.
LOSS OF DEMAND INPUT
SIGNAL
The DCM-2 board has the capability of
determining when the Demand input signal to the
drive is lost, and then responding in the method
most appropriate for the application. There are
three setup parameters that must be configured
in order to define this capability: “LOS Mode”,
“LOS Pos” and “DemLimLwr”. The “LOS Mode”
parameter determines how the drive should
respond to the loss of the Demand input signal.
It can be configured as “STAY” (which means the
drive holds its current position when the signal is
lost) or “GO-TO-POSITION” (which means the
drive moves to a predetermined position). If the
“Go-to-Pos” option is selected, the “LOS Pos”
parameter is used to determine what output shaft
position the drive must achieve when the input
is lost. Finally, a loss of signal is sensed by the
DCM-2 when the signal drops below the value
set by the “DemLimLwr” parameter. This value
is represented in mA of the Demand input signal
range. Therefore, the standard 3.2 mA value
normally used for this parameter suggests that
when the Demand input signal drops 5% below
the calibrated 0% value, the DCM-2 senses a lost
Demand input and executes the configured loss-
of-signal action.
Changing Loss (LOS) of Signal
Action
STEP 1 - From the HART
®
communicator
“Online” menu, move to the “Demand Setup”
menu and select the “LOS Mode” parameter.
This is accomplished by using the up and down
arrow keys to select the appropriate item in each
menu and then moving forward by pressing the
right arrow key. Follow the Menu Tree (Figure 1,
page 34) to navigate.
STEP 2 - With the “LOS Mode” parameter
selected, press the right arrow key to display the
two entry choices: “Stay” or “Go-to-Pos”. Use
the up and down arrow keys to select the desired
parameter.
STEP 3 - With desired choice selected,
push the F4 function key which is defined as the
ENTER key at the bottom of the display. Pushing
this key enters the selected parameter and reverts
the display back to the “Demand setup” main
menu. If the “Go-to-Pos” choice was selected, go
to STEP 4, if “Stay” was selected, go to STEP 6.
STEP 4 - After entering “Go-to-Pos”, select
the “LOS Pos” parameter and use the right arrow
key to display the modifiable entry block. Unless
otherwise specified, this value is set to 50% at
the factory. Using the alphanumeric keypad,
enter the desired loss of signal position as a
percentage of full output shaft travel. Values
from -5% to 105% are valid.
STEP 5 - With desired value correctly typed
into the entry box, push the F4 function key which
is defined as the ENTER key at the bottom of the
display. Pushing this key enters the value and
reverts the display back to the “Demand Setup”
main menu.
STEP 6 - At the bottom of the “Demand Setup”
menu, the F2 function key should now be defined
as the SEND key. Push this key to execute the
change.