Delta RMC101 - Manual (Page 591)

Quadrature with Stepper Output 6.4
Transducer Interface Modules 6-47
FAULT + and - is an input from the drive or some other source that can be set up to trigger the
RMC to stop its target generator and stop generating step pulses. The user can select the active
state of this input by the Fault Active State bit in the axis’s Config word; by default the RMC is set-
up to fault when current stops flowing through the input. This way the axis will fault on loss of
control power. Bit 15 of the Status word is set if a Fault or Encoder error has occurred. The Auto
Stop parameter determines how the axis will stop when a fault occurs.
Quadrature Encoder Inputs
The RMC stepper module accepts signals from quadrature encoders. The A and B signals from
the encoder are decoded to generate a positive or negative count; the count is then used to
monitor the axis position. Each signal from the encoder is received into a differential line receiver
for compatibility with differential line driver encoders. The negative input is biased so some
encoders with open collector or TTL outputs can also be used, though this is not recommended
due to the possibility of electrical noise.
Index (Z) Input
The index input is active for one count of each quadrature encoder revolution. It is used to qualify
or narrow the effective width of the home input to make the homing more repeatable; see Homing
a Quadrature Axis for details. The user may change the active state of this input by changing the
Home Active State bit in the axis’s Config word.
Home (H) Input
This input may be used in homing the system; see Homing a Quadrature Axis for details. This
input will be connected to a normally-off proximity switch. The user may change the active state
of this input by changing the Home Active State bit in the axis’s Config word.
Extend and Retract Travel Limit Inputs
The Extend Limit (CW) and Retract Limit (CCW) switch inputs tell the RMC that a travel limit has
been reached and can be configured to automatically halt the axis. By default the limit switches
are considered inactive when enough current is flowing through the RMC inputs. This way the
limit switches will look active to the RMC if control power is lost. The user may change the active
state by setting the Limit Switch Active State bit in the axis’s Config word.
The Auto Stop bits must be set to automatically stop the axis based on these limit inputs.
Note: There is only one bit in the Config word for both limit switches so both limit switches must
have the same active state.
If a limit switch is not used it should be wired in the inactive state or the Limit Switch Active State
bit must be configured to disable the inputs.
Motor Position Compensation
When quadrature encoder feedback is used, the RMC may be configured to compensate for
differences between the target and actual position of the motor. See Stepper Compensation for
details.
See also:
Stepper Wiring
Stepper Configuration
Stepper LED Indicators
Stepper Specifications
Stepper Scaling
Stepper Compensation
Homing