Delta MMC120 - Manual (Page 124)

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TRANSDUCER COUNTS
TRANSDUCER COUNTS is the axis position read directly from the transducer counters
with no scaling. Internally, TRANSDUCER COUNTS are stored in an 18-bit counter,
but only the lower 16 bits are available through the read-back register. The display on
the PC shows the value of the 18 bit counter.
Why Bother?
Knowing the COUNTS is necessary for calculating the SCALE and OFFSET parameters.
It is also necessary to make sure that a positive drive causes the counts to increase.
Magnetostrictive Displacement Transducers (MDT)
MDTs are transducers that provide absolute position, in a manner similar to a radar and
doesn’t require a homing routine. The counts will be in the range of 2,500 to 65,000
when the MDT is working. The COUNTS field gets set to 0 when the MDT is not
working. The motion controller ignores a new reading if the new count is 250 counts or
more from the last count.
AXIS STATUS Word
The axis STATUS word contains 16 bits of information about the condition of the axis.
You can use any of the first eight error bits to trigger a STOP on the axis using the
AUTO STOP parameter.
Click here for the Axis Status Bit Map.
Error bits 2 through 8 are cleared whenever a 'G' command is given. Error bit 1 is cleared
after a 'P' command if a transducer is detected at that time.
NOTE: Bit 1 is the most significant bit (MSB; left-most bit), Bit 16 is the least
significant bit (LSB, right-most bit).
Tip: To display the individual fields of the STATUS word, select Status Bits from
the Window menu (or press CTRL+B) to display the Bit Status window.
Bit 1 - No Transducer
This bit is set and the corresponding front panel axis LED (light emitting diode) glows
red if the transducer does not respond at least once every 6 milliseconds. It causes a Hard
Stop or a Soft Stop, depending on the setting of AUTO STOP bit 9. This bit will stay on
until a new command is given to the axis.
Bit 2 - Transducer Noise