Reference Manual

16-Axis MACRO CPU Software Reference Manual
6 16-Axis MACRO Station MI-Variable Reference
If MI16 is set to 1, then the ASIC’s own encoder-loss status bit (bit 7 in the channel hardware status
word) for each encoder channel is copied into bit 8 of the matching node’s status flag word for
transmission back to the PMAC. Note that this reporting function is unrelated to the automatic encoder-
loss shutdown function using external circuitry that can be enabled with MI7 and reported in MI4.
In order for this encoder-loss detection to work properly, several conditions must apply:
• A B version or newer of the DSPGATE1/2 Servo/MACRO IC must be used (true on boards built
since Spring 1998).
• Differential encoders must be used.
• The A+, A-, B+, and B- encoder signals must be wired into the T, U, V, and W supplemental flag
inputs, respectively, as well as into the regular encoder lines.
• The socketed resistor SIP packs for the encoder channels must be reversed from their factory default
configuration. These SIP packs are installed at the factory so that pin 1 of the pack – marked with a
dot – is installed in pin 1 of the socket – marked with a bold white outline and a square solder pin on
the board. For this encoder-loss to work, the SIP-pack for each encoder must be reversed so that it is
at the opposite end of the socket. The SIP packs are:
Board Encoder 1 Encoder 2 Encoder 3 Encoder 4
ACC-24E2 RP22 RP24 RP22* RP24*
ACC-24E2A RP22 RP24 RP22* RP24*
ACC-24E2S RP19 RP21 RP27 RP29
*Resistor packs on Option 1 top board of 2-board assembly
• MI16 must be set to 1.
If the T, U, V, and W input flags are used for different purposes, such as Hall commutation sensors, or
sub-count information from an analog encoder interpolator, the state of the encoder-loss status bit would
appear random and arbitrary.
The state of the encoder-loss hardware status bit for a channel can be polled with MI927 for the node
mapped to the channel. If it has been set, it can be cleared by writing a 0 value to MI927.
Note:
As long as the socketed resistor pack for an encoder is reversed from the factory
default configuration, the 16-Axis MACRO Station will be able to detect
differential encoder loss and shut down on it, even without wiring the encoder
signals into T, U, V, and W. However, unless the signals are wired into these flag
lines and MI16 is set to 1, the 16-Axis MACRO Station will not be able to notify
PMAC exactly which encoder sustained the loss.
MS{anynode},MI17 Amplifier Fault Disable Control
Range: $00 - $FF
Units: none
Default: $00 (amplifier function enabled for all axes)
This variable controls whether the amplifier input to the machine interface channel mapped to each servo
node by SW1 is used as one of the conditions that creates a node fault to be sent back to the PMAC over
the MACRO ring.
The variable consists of eight bits; each bit controls the disabling of the amplifier fault input for one of the
nodes on the Station. A 0 in the bit specifies that the amplifier fault input is to be used (enabled); a 1 in
the bit specifies that the amplifier fault input is not to be used (disabled). The corresponding bit of MI18
determines the polarity of the input if it is enabled.