ADLINK PCI-8158 - Manual (Page 81)

Operation Theory 71
4.3.4 Servo alarm signal
The alarm signal is an output signal from motor driver. It tells
motion controller that there has something error inside servo
motor or driver. Once the motion controller receives this signal, the
pulses command will stop sending and the status of ALM signal
will be ON. The reasons of alarm could be servo motor’s over
speed, over current, over loaded and so on. Please check motor
driver’s manual about the details.
The logic of alarm signal must be set correctly. If the alarm logic’s
setting is not the same as motor driver’s setting, the ALM status
will be always ON and the pulse command can never be output-
ted.
4.3.5 Error clear signal
The ERC signal is an output from the motion controller. It tells
motor driver to clear the error counter. The error counter is
counted from the difference of command pulses and feedback
pulses. The feedback position will always have a delay from the
command position. It results in pulse differences between these
two positions at any moment. The differences are shown in error
counter. The motor driver uses the error counter as a basic control
index. The large the error counter value is, the faster the motor
speed command will be set. If the error counter is zero, it means
that zero motor speed command will be set.
At following four situations, the ERC signal will be output automat-
ically from the motion controller to the motor driver in order to clear
error counter at the same time.
1. Home return is complete
2. The end-limit switch is touched
3. An alarm signal is active
4. An emergency stop command is issued
4.3.6 Servo ON/OFF switch
The servo on/off switch is a general digital output signal on motion
controller. It is defined as the SVON pin on the connector. It can be
used for switching motor driver’s controlling state. Once it is turned