Chapter 4 Register Programming; Motion Control Registers; R0: Preset Pulse Counter (24 Bits) - Advantech PCI-1243U User Manual

Chapter 4 Register Programming

4.1 Motion Control Registers

Several motion control registers are used to control PCI-1243U. These
registers are used to store commands, speed, mode, number of pulses and
more. The following sections describe these registers in detail.

4.1.1 R0: Preset Pulse Counter (24 bits)

PCI-1243U has an internal preset countdown counter. By entering a num-
ber of pulses, this preset counter will begin counting down from that
point.
The preset counter decrements by one for each pulse output in the contin-
uous, zero return and preset operations. However, if the preset counter
operation mode is inhibited by the output mode command, the preset
counter will not count down.
The counter value (number of remaining pulses) can be read while in
operation or while stopped. To read the value, first select R0. The register
select timing latches the data into a 24-bit read buffer.
In preset operation, PCI-1243U places a number of positioning pulses in
this register, and then starts the operation. Once the operation has started,
the counter value is decremented with each pulse that is output. When the
number of pulses that have been output is equal to the value originally
entered in the preset counter, the value in the counter will be zero and
PCI-1243U will stop operation.
The allowable range is 0 to 16,777,215 (FFFFFF HEX).
If you enter 0 in the preset counter and write the start command, PCI-
1243U will not use the preset operation. When INT output is enabled,
PCI-1243U will output an INT signal.
If you stop the preset operation using the stop command or an external
signal, the number of remaining pulses will be saved in the preset
counter. By entering a new start command, PCI-1243U will continue to
output all of the remaining pulses.
After the preset number of pulses has been output, the value in the preset
counter will be 0.
If you want to restart the operation using the same number of pulses, you
will have to put the value in R0 again.
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