Rockwell Automation 57C421B Pulsetach Input Module/DCS 5000/AutoMax User Manual
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4Ć9
4.2.5
Mode Definition Register (Register 6)
Register 6 is a control register used to define the module's operating
mode. Refer to figure 4.10. This register is read/write.
WARNING
BITS 4, 5, 6, AND 7 ARE CONTROLLED BY THE OPERATING SYSTEM AND MUST
NOT BE WRITTEN TO BY THE USER. WRITING TO THESE BITS MAY RESULT IN
ALL OUT PUTS BEING TURNED OFF AND ALL TASKS IN THE RACK BEING
STOPPED. FAILURE TO OBSERVE THESE PRECAUTIONS COULD RESULT IN
BODILY INJURY.
Bit: 0
Description: External Latch Enable
Bit 0 is used to enable the external latch input. When this bit is set to
one and the external latch input makes the transition specified by
register 6, bit 14, the value in the counter at that time will be stored
in registers 0 and 1.
Bit: 1
Description: External Count Stop Enable
Bit 1 is used to enable the external count stop input. When this bit is
set to one and the external count stop input is equal to the condition
specified by register 6, bit 12, the counter will stop counting.
Bits: 2 and 3
Description: Count Reverse and Count Forward
Bits 2 and 3 are used to define the counter direction when the
clear/origin input is used to initialize the absolute position of an
external device. When the clear/origin input is used for this purpose,
you must define whether the counter should be counting forward or
backward when the marker pulse resets the counter. Refer to
register 6, bit 10 for more information.
Set bit 2 to one if the counter should be counting in the reverse
direction. Set bit 3 to one if the counter should be counting in the
forward direction.
Bit: 4
Description: System use only.
Bit: 5
Description: System use only.
Bit: 6
Description: System use only.
Bit: 7
Description: System use only.
Bit: 8
Description: Type of Pulsetach
Bit 8 defines the type of pulsetach connected to the module. This bit
should be set to zero if a quadrature (A and B) pulsetach is
connected. A quadrature pulsetach is required to count forward and
reverse pulses.
This bit should be set to one if a singleĆinput pulsetach is
connected. A singleĆinput pulsetach may be connected to either the
A or B inputs. Note that with a singleĆinput pulsetach, the counter