
B–62073E–1/04 2. INTERFACE BETWEEN CNC AND PMC–NA OR NB
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NOTE Tool posts and BMI
The Series 15–TT controls a lathe which can turn two workpieces simultaneously two tool
posts by operating independently.
The Series 15–TT can be used for either of the following:
– A lathe that has two spindles and allows simultaneous turning of two workpieces with two
tool posts (Two spindles, two tool posts)
– A lathe that has one spindle and allows simultaneous turning of one workpiece with two
tool posts (One spindle, two tool posts)
The DI/DO signals of the BMI can be classified by relationships with the tool post, as described
below:
(a) DI/DO signals shared by two tool posts
A single set of signals is shared by the first and second tool posts to implement particular
functions. The signals to be shared include: the signal that selects the basic operation
mode of the control unit, reset signal, and emergency stop signal. For example, when the
memory operation mode is selected, both tool posts enter the memory operation mode.
Or, when the rest or emergency stop signal is issued, a reset or emergency stop occurs
in both tool posts.
(b) Individual tool post DI/DO signals
Two individual signals having the same function are provided for the first and second tool
posts. The names of these signals end with #1 or #2. #1 indicates that the signal is
provided for the first tool post. #2 indicates that the signal is provided for the second tool
post.
These signals can be divided into the following two groups:
– Spindle control DI/DO signals
These signals include the following:
i. Spindle speed signals: RO0 to RO15
ii. Maximum spindle speed signals: MR0 to MR15
iii. Actual spindle speed signals: AR0 to AR15
iv. Spindle motor command voltage signals: RISGN, RI0 to RI12
When the lathe has two spindles and two tool posts, the DI/DO the individual tool post
signals are used to control the spindle of the corresponding tool post.
When the lathe has one spindle and two tool posts, the DI/DO signals provided for the
first tool post are used to control the spindle shared by the tool posts.
– DI/DO signals other than those for spindle control
The signals in this group include: the feedrate override signal, miscellaneous function
code signals, and the strobe signal. The cutting feedrates of the tool posts can be
overridden independently. Different miscellaneous function code signals or strobe
signals can be sent to the two tool posts.
The DI/DO signals provided for individual control axes control only one of the tool
posts. In that sense, signals of this type can be said to be provided for individual tool
posts. However, the names of these signals do not end with #1 or #2. This is because
the control axes are not classified by tool posts, but are identified by unique control
axis numbers in the entire system.
In the basic configuration of the Series 15–TT, each tool post has two axes, that is,
there are a total of four control axes. An axis can be added to each tool post to
increase the total to six axes.