Projecta IM2000 Instrucciones de operaciones descargar pdf (Pagina 59)

The Resolution Select (MSEL) Inputs

One of the key features of the 34 pin header is the availability of the resolu-

tion select inputs on P1. This allows the user to take external control of the

driver output resolution, enabling the user to switch the output resolution “on-

the-fly”.

An example would be to switch to a lower resolution (higher velocity, lower

positional accuracy) during a long move. When the move nears completion,

switch back to a higher resolution (lower speed, greater positional accuracy) to

accurately position the axis. This on-the-fly “gear shifting” facilitates high speed

slewing combined with high resolution positioning at either end of the move.

The microstep resolution is synchronized with the step clock input. If the

resolution change does not fall on a full step, the IM483 will readjust itself at

the next pulse that would overshoot the fullstep position. This feature allows

the IM483 to readjust the motor position regardless of the output resolution

selected during a resolution change.

These inputs are non-isolated and are active when in a logic LOW state (if left

open or floating the input is considered to be OFF). They are pulled-up to +5

VDC via 1.5 kΩ resistors. These inputs may to be interfaced via an external

switch or sinking output on a control device. Figure A.3 shows the resolution

select inputs connected using a TTL interface method. Note that the DIP

switch (SW1) is still in place and may be used to control the resolution. If

controlling the resolution externally, the four switches need to be in the “OFF”

position.

The driver output resolution has two modes of operation: decimal and binary.

The modes are switched by changing the logic state of MSEL 3. If MSEL 3 is

in a logic HIGH (open/floating) state the output resolution will be in decimal

mode. Binary mode is entered by sinking MSEL 3 to a 0 state.

Typically, in cases where resolution is being switched on-the-fly, only one mode

will be used. The desired mode may be selected by positioning the DIP switch

(SW1:4) for MSEL 3 to the appropriate state for the selected mode, then the

resolution may be controlled by changing the states of MSEL 0 - 2 as needed,

thus using only 3 outputs on the control device.

NOTE! When controlling the driver output resolution externally,

the DIP switches (SW1) should be in the “OFF” position.

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Projecta IM2000 Instrucciones de operaciones Pagina 59