65
80-1403-01, Rev. 3
POSITION AND DEMAND
MISMATCH
If the shaft position and the Demand do not
match and the motor is not running, then some
factor is preventing the DCM-3 from running the
motor. The fieldbus interface provides extensive
information for finding this factor.
The Transducer Block contains two
parameters that summarize why the motor is not
running: one parameter for CW and one for CCW.
The parameter names are CW Inhibitor and CCW
Inhibitor. If the parameter is 0 (has not bits set), the
motor should run that direction. If the parameter is
not 0, the DCM-3 will not try to run the motor that
direction. The bits that show in the parameter are
the reasons the motor is not running that direction.
INHIBITORS
If the inhibitor parameter is 0 but the motor
is not running, power to the motor is being
blocked by something over which the DCM-3
microcomputer has no control. Possibility 1 listed
below should lead to a Stall alarm (page 23). The
other possibilities should create a Stop/Limit alarm
(page 22).
1. The motor is stalled, and cannot travel. This
condition is unlikely if the motor operated
properly with the Handswitch. For more
information on the Handswitch, refer to
Checking Handswitch Operation (page 62).
2. The Handswitch or an Over-travel Limit Switch
is preventing power from reaching the motor.
Make certain the Handswitch is in AUTO. The
Handswitch and the DCM-3 both use the same
over-travel limits, so if the limits do not prevent
Handswitch operation, they should not prevent
DCM-3 operation.
3. Wire jumpers are missing from terminals F-N
and terminals D‑M on the field wiring terminal
block. Most installations of Group 11 actuators
with Foundation Fieldbus compatibility require
these wire jumpers. Check the wiring diagram
that came with the specific actuator.
4. The output section of the DCM-3 is not
delivering power to the motor.
5. The DCM-3 fuse is cleared. This fuse is rated
at more than twice the motor current, and the
Beck motor has no significant inrush current.
Therefore, only in very rare circumstances
is the fuse cleared. These circumstances
are generally wiring errors during customer
installation. For the fuse location, refer to
DCM-3 LAYOUT (page 18).
Label
Cause of Motor Not Running
OverTrq/Thrust
Not active in Group 14
Balance
Demand indicates motor should not run this direction.
Stall
Stall.
Supervisory
The DCM-3 is initializing.
Switch Block
Not used in Group 14 actuators
Bad Pos Sig
The Position signal from the CPS-5 is not acceptable
Bad Dem Sig
Not used on fieldbus systems.
Local Cal
Not used on fieldbus systems.
Содержание 14-100
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