12 • Chapter 2 Getting Started DMC-1500
If you are not sure about the potential of the ground levels, connect the two ground
signals (amplifier ground and earth) by a 10 KΩ resistor and measure the voltage across
the resistor. Only if the voltage is zero, connect the two ground signals directly.
The amplifier enable signal is used by the controller to disable the motor. It will disable
the motor when the watchdog timer activates, the motor-off command, MO, is given, or
the position error exceeds the error limit with the "Off-On-Error" function enabled (see
the command OE for further information).
The standard configuration of the AEN signal is TTL active high. In other words, the
AEN signal will be high when the controller expects the amplifier to be enabled. The
polarity and the amplitude can be changed if you are using the ICM-1100 interface
board. To change the polarity from active high (5 volts = enable, zero volts = disable) to
active low (zero volts = enable, 5 volts = disable), replace the 7407 IC with a 7406. Note
that many amplifiers designate the enable input as ‘inhibit’.
To change the voltage level of the AEN signal, note the state of the resistor pack on the
ICM-1100. When Pin 1 is on the 5V mark, the output voltage is 0-5V. To change to 12
volts, pull the resistor pack and rotate it so that Pin 1 is on the 12 volt side. If you
remove the resistor pack, the output signal is an open collector, allowing the user to
connect an external supply with voltages up to 24V.
On the ICM-1100, the amplifier enable signal is labeled AENX for the X axis. Connect
this signal to the amplifier (figure 2.3) and issue the command, MO, to disable the motor
amplifiers - often this is indicated by an LED on the amplifier.
Step C. Connect the encoders
For stepper motor operation, an encoder is optional.
For servo motor operation, if you have a preferred definition of the forward and reverse
directions, make sure that the encoder wiring is consistent with that definition.
The DMC-1500 accepts single-ended or differential encoder feedback with or without an
index pulse. If you are not using the AMP-11X0 or the ICM-1100 you will need to
consult the appendix for the encoder pinouts for connection to the motion controller. The
AMP-11X0 and the ICM-1100 can accept encoder feedback from a 10-pin ribbon cable
or individual signal leads. For a 10-pin ribbon cable encoder, connect the cable to the
protected header connector labeled X ENCODER (repeat for each axis necessary). For
individual wires, simply match the leads from the encoder you are using to the encoder
feedback inputs on the interconnect board. The signal leads are labeled XA+ (channel
A), XB+ (channel B), and XI+. For differential encoders, the complement signals are
labeled XA-, XB-, and XI-.
Note: When using pulse and direction encoders, the pulse signal is connected to CHA
and the direction signal is connected to CHB. The controller must be configured for
pulse and direction with the command CE. See the command summary for further
information on the command CE.
Step D. Verify proper encoder operation.
Start with the X encoder first. Once it is connected, turn the motor shaft and interrogate
the position with the instruction TPX <return>. The controller response will vary as the
motor is turned.
At this point, if TPX does not vary with encoder rotation, there are three possibilities:
1. The encoder connections are incorrect - check the wiring as necessary.
2. The encoder has failed - using an oscilloscope, observe the encoder signals. Verify that both channels
A and B have a peak magnitude between 5 and 12 volts. Note that if only one encoder channel fails,
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