Installation guide

Mint™ v4 Advanced Programming Guide
14 MN1270 02.2002
In order to utilize the functionality of the ASIC’s hardware position latching facility the functionality of
fast position latching has been modified.
Each controller supports a different number of axes and fast interrupt inputs:
Controller Fast Interrupt
Inputs
Axes Auxiliary
Encoders
NextMove BX 4 4 1
NextMove PC 1 8 0
NextMove PCI
2
(main board only) 4 8 1
NextMove PCI (main board + 1 expansion card) 8 8 2
MintDrive 2 1 1
ServoNode 51 2 1 1
Although the hardware available differs between controllers the keywords and functionality is the same
across all controllers. The only functional difference being that the controllers which use the encoder
ASIC (NextMove PCI, MintDrive and ServoNode 51) perform their position capture within hardware
and are consequently much faster.
On NextMove PCI, in order to latch position of a stepper axis, the ASIC must be put into the correct
mode. Each ASIC is capable of supporting one servo axis and one stepper axis. Each axis is associated
with a channel and this can be read with the
AXISCHANNEL keyword. The VIEW CONFIG keyword can
also be used to display this information in the terminal.
A channel (ASIC) can be switched to allow capture of the servo or stepper axis that is using that
channel. This is done with the
CHANNELCONFIG keyword. This must be done before attempting to
call any of the FASTxxx keywords otherwise an error ‘Incorrect Channel Setup’ will be returned
indicating that the channel an axis is using is not setup to allow capture on that axis.
The flexibility of the fast position latch capability within Mint v4 has been expanded, however this
means that the setup of the axis and the inputs may need to be configured.
The FASTSELECT keyword allows axes to be assigned a fast position latch input. When this assigned
input becomes active the position of all associated axes is latched. For Example:
FASTSELECT[0,1,2,3] = 1,1,2,3
will map: axis 0 to input 1
axis 1 to input 1
axis 2 to input 2
axis 3 to input 3
By default all axes (including the auxiliary encoders) are mapped to fast position latch input 0.
In the case of NextMove PCI all axes on the expansion card are mapped to input 20.
The FASTLATCHMODE keyword sets the mode of the position latching. This controls when the axis
position can be latched. The available modes are:
• 0 – Always
• 1 – Smart
• 2 – Manual
• 3 – Never (Off)
In mode 0: The latch preventing further position capture is cleared as soon as the position has been
captured.
In mode 1: Further latching is prevented until the fast position latch handler has completed.
In mode 2: Further latching is prevented until the user manually clears the hardware latch using the
FASTENABLE keyword.
In mode 3: The position capture is disabled.
2
Fast position latching is only supported on the servo axes of a NextMove PCI controller