84
Manual – IPOSplus®
6
Cam controllers
Position Detection and Positioning
• How can positioning be continued once the enable has been revoked?
• Set the bits H453.0 (ModuloCtrl variable and TargetReset_Off bit).
• How does the axis act when the _AxisStop( AS_PSTOP ) command is activated
during positioning?
• The drive waits at the positioning ramp; the actual position is displayed when the
axis stops. To continue positioning, the target position must be given a new value
(for example, change the increment value by 1 bit). Instead of using the
_AxisStop( AS_PSTOP ) command, use _AxisStop( AS_RSTOP ). In this case,
the target position would be stored when the H453.0 bits (ModuloCtrl variable and
TargetReset_Off bit) were activated.
6.8 Cam controllers
You can use cam controllers to set or reset outputs depending on the position of a drive.
This function lets you control additional actuators, such as pneumatic cylinders, start a
second axis (e.g. for rounding the path contour in a xy portal) or monitor two axes in the
same operating range for collision.
Each MOVIDRIVE
®
comes equipped with a standard cam controller with one output. A
new output is formed every time the command is processed in the IPOS
plus®
program.
An unlimited number of outputs is theoretically possible, but the number of outputs is
practically limited by the IPOS
plus®
program length and the acceptable execution time.
New MOVIDRIVE
®
units (MDx_A / MCV / MCS / MCF as of version .14, MCH as of ver-
sion .13 and MDx_B) and the technology options have an expanded cam controller with
eight outputs that is cyclically calculated in the background by the firmware.
You initialize a cam controller in the drive and evaluate the status of the cams with the
GETSYS command.
The GETSYS command accesses a data structure. The bit with the highest value of the
first variable in this data structure decides which cam controller the GETSYS command
refers to (Bit 31 = 0: Standard cam control with bit 31 = 1: Expanded cam control).
If both cam controllers are available in the unit on site, SEW recommends to initially use
the expanded cam control. It is also possible to use both cam controllers at the same
time. The outputs of both cam controllers can be issued on the same binary output word
by issuing the outputs of the standard cam controller in the lower 2 bits and the outputs
of the expanded cam controller in the higher 4 bits, shifted two places to the left.
INFORMATION
If the output bit of a cam is copied to a binary terminal output, the output is set 1 ms
later, as with all bits that are copied to outputs in IPOS
plus®
.
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