HEIDENHAIN ND 287 User Manual - Manual (Page 55)

ND 287
55
I – 5 Ser
ies of measur
ements and statistical
pr
ocess
c
ontr
ol Statistical distribution
The STATISTICAL DISTRIBUTION form allows you to define the
calculation and graphic display of the distribution density curve in the
histogram:

In the SPC SETUP submenu, select STATISTICAL DISTRIBUTION
and press the ENTER key to open the form.
 Press the DISTRIBUTION soft key to select the type of statistical
distribution. For example, form and position tolerances, which have
a natural lower limit (i.e. they cannot become less than zero), are
processes with a left-hand limit. The following settings are available:
 SYMMETRIC
 LIMITED TO LEFT
 LIMITED TO RIGHT
Measured value recording
The RECORD VALUES form allows you to define the trigger for
recording the measured values for statistical process control:
 In the SPC SETUP submenu, select RECORD VALUES and press
the ENTER key to open the form.
 Press the RECORD soft key to select one of the following settings
in the RECORD field:
 External signal at connection X41 (pin 22 or 23)
 ENTER key
Deleting SPC statistics
Use DELETE STATISTIC to delete all measured values stored in
memory and to restart statistical process control:
 Call the SPC menu.
 Select DELETE STATISTIC and press the ENTER key to confirm, or
press the C key to cancel. If you press ENTER, the ND will clear all
recorded measured values from the FIFO memory.
Fig. I.61 Statistical distribution
Fig. I.62 Measured value recording
Screen
 The ND stores the data recorded during statistical
process control in non-volatile memory. After the ND
has been switched on again and SPC has been
resumed, it will continue using the previously recorded
data.
 The stored measured values can also be cleared. Use
DELETE STATISTIC to clear all measured values from
memory (see "Deleting SPC statistics" on page 55).
Fig. I.63 DELETE STATISTIC parameter