HEIDENHAIN ND 282B User manual

English (en)
4/2001
Measured Value
Displays
User’s Manual
ND 282 B

2
Numeric keypad
with decimal point
Status display with indicators
Display of actual value and input
(8 decades with algebraic sign)
HEIDENHAIN
789
456
123
0.CL
MOD
REF SET START PRINT inch
MIN ACTL MAX DIFF
= <>
21

3
Key Function
• Set datum
• Transfer input value
• Set display to value from P79 (P80!)
• Leave parameter list
• Select datum
• Page backwards in parameter list
• Start series of measurements
• Switch display for measurement series
• Start measured value output “PRINT”
• Select parameter after switch-on
• Page forward in parameter list
• Delete entry
• Set display to zero (P80!)
• CL plus MOD: select parameter list
• CL plus number: select parameter
• Algebraic sign
• Reduce parameter value
• Decimal point
• Increase parameter value
MOD
Indicator Meaning
REF If the decimal points are also blinking:
Display is waiting for reference mark
traversing. If decimal points are not blinking:
Reference mark has been traversed—display
stores datum points in nonvolatile memory
Blinking: display is waiting for ENT or
CL to be depressed
inch Position values in inches
1 / 2 Selected datum point
PRINT Blinking: Display is waiting for ENT to
be pressed for data output
SET Blinking: Display is waiting for input values
< / = / > Sorting and tolerance checking:
measured value smaller than lower limit /
within the limits / greater than upper limit
MIN
/ MAX / Series of measurements: Minimum /
maximum / greatest difference (MAX–MIN) /
current measured value
Blinking: Confirm selection or deselect
function
START Series of measurements is running
Blinking: Display is waiting for signal to
start series of measurements
DIFF / ACTL

4
Items supplied with ND 282 B
ND 282 B Measured value display unit,
benchtop model
Encoder input 11 µAPP Id. Nr. 344 998-xx
Power cord 3 m (9.9 ft)
User's Manual ND 282 B
Adhesive plug-in feet For stacking ND 282 B units
This manual is for the ND 282 B measured value
display with the following software number or higher:
354 394-01
The software number is indicated on a label on the
rear panel.
Items Supplied

5
Installation and Specifications
Rear Panel, Accessories 16
Mounting 17
Power Connection 18
Operating Parameters 19
List of Operating Parameters 21
Linear Encoders 24
BCD Interface (X33) 27
Switching Inputs and Outputs EXT (X41) 29
Distance-to-Go Mode 34
Displaying the Software Version 35
Locking the Keypad 36
Specifications 37
Dimensions 38
Contents
Contents
Working with the ND Display Units
Encoders and Reference Marks 6
Switch-On, Traversing the Reference Marks 7
Datum Setting 8
Finding Minimum and MaximumValues 9
Sorting and Tolerance Checking 12
MeasuredValue Output 13
Error Messages 15

6
Position Encoders and Reference Marks
The ND 282 B display unit is designed for use with photo-
electrical linear encoders with 11 µAPP sinusoidal signals:
primarily for HEIDENHAIN MT length gauges with 11 µAPP.
The MT length gauges have one reference mark. The scales
of other photoelectric linear encoders (see “Linear Encod-
ers”) can contain one reference mark or many
distance-
coded
reference marks.
If there is an interruption of power, the relationship between
the position of the length gauge and the displayed position
value is lost. The reference marks on the position encoders
and the REF reference mark evaluation feature enable the
display unit to quickly reestablish this relationship again
when the power is restored.
When a reference mark is crossed over, a signal is generated
which identifies that position as a reference point. At the
same time, the display unit restores the relationship be-
tween length gauge position and display values which you
last defined by setting the datum.
To restore the datum on scales with distance-coded refer-
ence marks, you only need to traverse a maximum of 20 mm
for linear encoders.
Position Encoders and Reference Marks
Scale in Distance-coded
linear encoder reference marks
Reference mark
Reference marks on linear encoders

7
Turn on the power.
(Switch located on rear panel.)
•ND 282 B appears for two seconds.
•ENT ... CL 1) appears.
• REF indicator is blinking.
• Data interface shows error 7.
ENT...CL
Switch-on the reference mark evaluation
function.
• The position value that was last
assigned to the reference mark
position is displayed.
• REF indicator lights up.
• Decimal point is blinking.
5 , 6 9 7
Switch-On, Traversing the Reference Marks REF Mode
Crossing over the reference marks automatically switches the
display to REF mode: The last assignment of display values to
length gauge positions is stored in nonvolatile memory.
1) Press the CL key if you choose not to traverse the reference
marks. Note that, in this case, the relationship between
length gauge position and display value will be lost if the
power is interrupted or if the unit is switched off.
Û
Cross over the reference mark.
Move the plunger until the display starts
counting and the decimal point stops blink-
ing. The display is now ready for operation.
0
ä
1
For automation purposes, crossing over the reference marks
and the display ENT ... CL can be disabled with parameter P82.
Switch-On, Traversing the Reference Marks

8
Datum Setting
The datum setting procedure assigns a display value to a
known position. With the ND 200 series, you can set two
separate datum points.
There are several ways to set the datum:
• Enter a numerical value, or
• Transfer a value from an operating parameter
(see P79, P80), or
• By external signal
Select datum 1 or 2.
After datum setting: Assignment of measured values to
positions
Without datum setting: unknown assignment of measured
values to positions
Z
?
?
?
?
?
Enter numerical value (here 5),
SET blinks.
5
You can switch between datums 1 and 2 as desired. Datum 2
can be used, for example, for working with incremental dimen-
sions.
When you switch back to datum 1, the display unit resumes
display of the actual position of the MT.
Datum Setting
Confirmthe entered numerical value.

9
Series of measurements: The MIN, MAX and DIFF values of an
uneven surface
Example: Measurement series for determining eccentricity
e
Finding Minimum and Maximum Values
DIFF
MAX
MIN
ACTL
Finding Minimum and Maximum Values from a
Series of Measurements
After a series of measurements has been started, the display
transfers the first measured value to the memory for minimum
and maximum values. Every 0.55 ms, the display compares the
current measured value with the memory contents: A new
value is stored if it is greater than the stored maximum value or
smaller than the stored minimum value. At the same time, the
display calculates and stores the difference DIFF between the
current MIN and MAX values.
Display Meaning
MIN Minimum value from the series of measurements
MAX Maximum value from the series of measurements
DIFF Difference MAX – MIN
ACTL Current measured value
Starting the measurement series and selecting the display
You can start the series of measurements either by pressing
MOD and selecting the desired display—as described on the
following pages—or by external signal over the switching
inputs at the D-sub connection EXT (see section on X41).
When a series of measurements is started, the internal MIN/
MAX/DIFF memory is reset.

10
Finding Minimum and Maximum Values
Starting a series of measurements
Select the display for a series of meas-
urements.
The selected indicator blinks (here, MAX).
Confirm selection.
Repeatedly
MOD
... until the START indicator blinks.
MOD
Repeatedly
Switching between MIN, MAX, DIFF and ACTL displays
It is not possible to switch between the displays as
described below if the switching input for external
control of the series of measurements (pin 6 on
D-sub connection EXT) is active.
As an alternative, you can select the display with operating
parameter P21 (see “Operating Parameters”).
Select the new display of a series of
measurements.
The selected indicator blinks (here, MIN).
Confirm the change.
Repeatedly
MOD
The display now shows the smallest value measured during the
current series of measurements.
Indicator preselection
Press MOD to start the series of measurements and select the
display with the indicators.
Operating parameter P86 allows you to define which indicator
is displayed first when MOD is pressed.
Start the series of measurements.
MAX
START
MIN