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WARNING
Carefully follow the on-screen warnings
and messages when proceeding, because
changing drive setup parameters can cause
the drive to reposition. This can adversely
affect the process and cause potentially
dangerous conditions.
STALL PROTECTION
The DCM-2 board provides protection of the
drive motor and gearing in the event of a stalled
condition. The board accomplishes this by
sensing that the drive is unable to balance for a
set period of time known as the “stall time”. If the
DCM-2 is unable to balance the drive for a period
greater than the stall time, it shuts off power to the
motor and prevents the drive from continuing to
operate against the stall. Resetting the drive and
restoring normal operation is achieved in several
ways: Reversing the Demand signal to the drive,
performing a stall reset procedure (see Manual
Operation Menu, Figure 1, page 34), performing
a board reset procedure (see Diagnostics Menu,
Figure 1, page 34), or cycling the drive ac power.
Changing Stall Time
STEP 1 - From the HART
®
communicator
“Online” menu, move to the “General Setup”
menu and select the “Stall Time” 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 “Stall Time” parameter
selected, again press the right arrow key to
display the modifiable entry box, and using
the alphanumeric keypad, type in the desired
stall trigger time value. It is normally set to a
maximum of 300 seconds, but can be changed to
a minimum of 30 seconds.
WARNING
It is possible that the stall time can be set
to a value less than the full travel time of
some drives. This could lead to false stall
conditions when making very large changes.
Typically, this would only occur during start-
up, shut down or some other condition that
might require a large change in Demand from
the controller.
STEP 3 - With the 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 “General
Setup” main menu.
STEP 4 - At the bottom of the “General 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 drive setup parameters can cause
the drive to reposition. This can adversely
affect the process and cause potentially
dangerous conditions.
OVERTRAVEL ANNUNCIATION
When communicating with the DCM-2 via the
275 HART
®
Communicator, a number of different
informational messages may be displayed for
certain conditions that may exist. One such
message is “H/S in STOP or drive at limit sw”.
This is displayed anytime the DCM-2 is attempting
to reposition the output shaft, but is unable to due
to a break in the electrical power to the motor.
This can happen if the Handswitch is put in
STOP or if an over-travel limit switch is open.
Normally, this is a useful message that should
be displayed; however, in certain situations like
split range operation (see split ranging, page
57), it can become a nuisance. For example, in
a split range operation one or more of the drives
will be interpreting the Demand input signal as
out of range (i.e., either above 100% Demand or
below 0% Demand) and will be against an over-
travel limit switch at any given time. Since this is
normal for split range operation, the message will
be a nuisance rather than informational.
Setting the “Overtravel Annunciate” feature
to “Ignore” will eliminate the message, but only
when the Demand signal is above 100% or below
Continued