HEIDENHAIN NPD 281 User Manual v.3

ND 281
NDP 281

User's Manual

ND 281
NDP 281

Measured value
display

5/97

Display of actual value and input

(7-segment LED, 9 decades with algebraic sign)

Numeric keypad
with decimal point

789

456

REF

=

<>

2

1

SET

MIN ACTL MAX DIFF

START PRINT

in.

123

0

.

–CL

HEIDENHAIN

Status display
with indicators

2

Key Function

• Set datum

• Transfer input value

• Set display to value from P79 (P80!)

• Leave parameter list

• Select datum

• Page backwards in parameter list

MOD

• Start series of measurements

• Switch display for series of measure­ments

• 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

Indicator Meaning

REF If decimal points are additionally 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
in. Position values in inches
1 / 2 Selected datum point
PRINT Blinking: Display is waiting for ENT to

be depressed for data output
SET Blinking: Display is waiting for input

values

< / = / > Sorting and tolerance checking:

measured value smaller than lower

sorting limit / within the sorting limits /

greater than upper sorting limit

/

MAX / Series of measurements: Minimum /

MIN
DIFF / ACTL 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

3

Items delivered with ND 281

Measured value display unit,
ND 281A bench-top design
Encoder input 11 µA

ND 281V

Encoder input 1 V

Power cord 3 m (9.9 ft)

Items Delivered

User's Manual ND 281/NDP 281
Adhesive plug-in feet For stacking ND 281 units

Items delivered with NDP 281

NDP 281 Measured value display unit,

Encoder input 11 µA

Power terminal
User's Manual ND 281/NDP 281

PP

This manual is for the measured value display
units ND 281 and NDP 281 with the following
software number or higher:

Id. Nr 283 481 ..

PP

Id. Nr 322 353 ..

for panel mounting

Id. Nr 289 214 ..

PP

246 181-01

The software number is indicated on a label on the

4

rear panel.

Contents

Working with the ND Display Units

Position Encoders and Reference Marks 6
Switch-On, Crossing Over the Reference Marks 7
Datum Setting 8
Finding Minimum and Maximum Values 9
Sorting and Tolerance Checking 12
Measured Value Output 13
Display Freeze 14
Error Messages 15

Installation and Specifications

Rear Panel; Accessories 16
Mounting 18
Power Connection 19
Operating Parameters 20

List of Operating Parameters 22

Linear Encoders 25
RS-232-C/V.24 Interface (X31) 30
Switching Inputs and Outputs EXT (X41) 35
Distance-To-Go Mode 40
Specifications 41

Dimensions 42

Contents

5

Position Encoders and Reference Marks

The ND 281 and NDP 281 display units are primarily intended
for use with photoelectrical linear encoders with sinusoidal
11-µA
MT length gauges with 11 µA

These length gauges have one reference mark. The scales of
other photoelectric linear encoders (see “Linear Encoders”)
can contain one reference mark or several
reference marks.

or 1-VPP signals: primarily for HEIDENHAIN

PP

PP

.

distance-coded

Scale in Distance-coded
linear encoder 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 re-establish 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 between

Position Encoders and Reference Marks

length gauge position and display values which you last
defined by setting the datum.

If the linear encoders have distance-coded

reference marks,
you only need to traverse a maximum of 20 mm to restore
the datum.

6

Reference mark

Reference marks on linear encoders

Switch-On, Crossing Over the Reference Marks

REF Mode

➤➤

➤

➤➤

0

ENT...CL

5 . 6 9 7

For automation purposes, crossing over the reference marks
and the display ENT ... CL can be disabled with parameter
P82.

Turn on power.

1

(Switch located on rear panel.)

•

• Indicator REF is blinking.

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.

Cross over the reference mark.

Move the plunger until the display starts
counting and the decimal point stops blink-

⇔

ing. The display now is ready for operation.

1)

is displayed.

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 cross over 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.

Switch-On, Crossing Over the Reference Marks

7

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

Datum Setting

(see P79, P80), or

• By external signal

Select datum 1 or 2.

Enter numerical value (here, 5).

5

Confirm the entered numerical value.

You can switch between datums 1 and 2 as desired. Datum 2
can be used, for example, for working with incremental
dimensions.

When you switch back to datum 1, the display unit resumes
display of the MT's actual position.

Z

?

?

?

?

?

Without datum setting: unknown assignment of measured values to

positions

Z

20˜

15˜

10˜

5˜

0

8

After datum setting: Assignment of measured values to positions

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

MAX

ACTL

Series of measurements: The MIN, MAX and DIFF values of an uneven
surface

DIFF

MIN

Starting the series of measurements 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 (X41, see page 34).
When a series of measurements is started, the internal MIN/
MAX/DIFF memory is reset.

AX

r

M

2e = r

MAX

Ð r

MIN

e = DIFF

2

IN

r

M

Example: Series of measurements for determining eccentricity

e

Finding Minimum and Maximum Values

e

9

Starting a series of measurements

Switching between MIN, MAX, DIFF and ACTL displays

repeatedly

MOD

Select the display for a series of
measurements.

The selected indicator blinks (here, MAX).

MAX

Confirm selection.

repeatedly

... until the indicator START blinks.

MOD

START

Start the series of measurements.

Finding Minimum and Maximum Values

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.

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”).

repeatedly

MOD

Select the new display of a series of
measurements.

The selected indicator blinks (here, MIN).

MIN

Confirm the change.

The display now shows the smallest value measured during

the current series of measurements.

10

Starting a new series of measurements

repeatedly

MOD

START

Ending a series of measurements

repeatedly

MOD

Select the indicator START.

The indicator START blinks.

Start a new series of measurements.

Select the active indicator (MIN, ACTL,
MAX, DIFF).

The indicator that lit up last blinks.

End the series of measurements.

Finding Minimum and Maximum Values

11

Sorting and Tolerance Checking

In the sorting and tolerance checking mode, the display unit
compares the displayed value with the programmed upper
and lower sorting limits. The sorting and tolerance checking
mode is enabled and disabled with operating parameter P17.

Entering sorting limits

Part 1

Sorting limits are entered in operating parameters P18 and
P19 (see “Operating Parameters”).

Sorting signals

The indicators and switching outputs at D-sub connection
EXT (X41, see page 34) sort the display value into one of three
classes.

Sorting and Tolerance Checking

Display Meaning
= Measured value is within sorting limits
< Measured value is smaller than lower sorting limit
> Measured value is greater than upper sorting limit

Operating parameters for sorting and tolerance checking

Sorting ON/OFF
Lower sorting limit
Upper sorting limit

12

Part 2

Part 3

Example: Upper sorting limit = 26.02 mm

Lower sorting limit = 26.00 mm

Accept

gut

Rework

Nacharbeit

Reject

Ausschu§˜

Measured Value Output

For technical information on the RS-232-C/V.24
data interface (X31), information on the data
format, etc., see the chapter “RS-232-C/V.24
Interface (X31)”.

Measured values can be output over the RS-232-C/V.24
interface (X31), for example to a printer or PC.

There are several ways to start measured value output:

➤➤

➤ Press MOD repeatedly until the indicator PRINT blinks,

➤➤

then start measured value output with ENT;

or

➤➤

➤Input the command STX (Ctrl B) over the RXD input of the

➤➤

RS-232-C/V.24 interface (X31);

or

➤➤

➤ Input a signal for measured data output (Pulse or Contact)

➤➤

at the D-sub connection EXT (X41).

PC

789

456

START PRINT

MOD

in.

123

0.–CL

REF21 SET

=

<>

MIN ACTL MAX DIFF

HEIDENHAIN

The RS-232-C/V.24 interface (X31) enables you to connect a printer or
a PC to your display unit

Measured Value Output

13

Display Freeze

With the latch command, the display can be stopped for any
period of time. The internal counter remains active.
Parameter P23 selects the “display freeze” mode and offers
three settings:

• Concurrent display, no display freeze — the display value

Display Freeze

is the current measured value.

• Frozen display — display value is frozen and is updated
with each signal for measured value output.

• Frozen/concurrent display — display remains frozen as
long as the latch signal is present; after the signal, the
display resumes continuous display of the current
measured values.

14

Position

Latch
signal

Frozen
display

Frozen/
concurrent
display

0

РРРРРРРРРРРРРРРРРРРРРРРРРРРРРРРРР

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

0.000

5

0.000

0.004

0.005

0.000

0.000

0.006

0.000

0.007

0.008

10

0.000

0.000

0.009

0.000

0.010

0.011

0.000

0.000

0.012

0.014

0.013

0.014

15

0.014

0.014

0.014

0.014

0.014

0.014

0.014

0.014

0.014

20

0.014

0.014

0.014

0.014

0.014

0.014

0.014

0.014

0.014

0.023

0.024

25

0.014

0.014

0.025

0.014

0.026

0.027

0.014

0.014

0.028

30

0.030

0.029

0.030

0.030

0.030

Ð

0.030

0.030

0.030

0.030

Error Messages

Display Problem

Last measured value has not been output
The external device is not connected, no

DSR signal (only displayed once!)
Data interface: Parity error or wrong transfer

1)

format
Incorrect input value
Overflow due to external setting (value for

P79 too high)
Overflow trigger limit 1
Overflow trigger limit 2
Overflow lower sorting limit
Overflow upper sorting limit
The encoder signal is too weak. The scale

may be contaminated.

1)

The input frequency for this encoder input
is too high. This can occur when the scale
is moved too fast.

Internal counter overflow

1)

1)

Error during traverse of the reference

1)

marks

1)

These errors are important for the attached device. The
error signal (pin 19) at D-sub connection EXT is active.

Display Problem

1)

If these errors persist, contact your
service agency.

1)

Offset compensation values for encoder

Error Messages

signals have been erased: contact your
service agency.

Check the operating parameters. If this
error persists, contact your service
agency.

Other error displays

If all decimal points light up, the measured value is too
great or too small:

➤➤

➤Set a new datum

➤➤

or

➤➤

➤ Traverse back.

➤➤

If all sorting signals light up, the upper sorting limit is
smaller than the lower limit:

➤➤

➤ Change operating parameters P18 and/or P19.

➤➤

To clear error messages:

When you have removed the cause of the error:

➤➤

➤ Clear the error message with the CL key.

➤➤

Delete error messages ERROR 80, 83, 84, 86.

15

Switch device off!

Rear Panel

Ports X1, X31 and X41 comply with the
recommendations in EN 50 178 for separation
from line power.

Encoder input X1

HEIDENHAIN flange socket 12-pin
Input signals 1 V
Maximum encoder cable length 60 m (197 ft)

Rear Panel, Accessories

Maximum input frequency 200 kHz

RS-232-C/V.24 data interface (X31)

25-pin D-sub connection (female)

Switching inputs and outputs EXT (X41)

25-pin D-sub connection (male)

Accessories

Connecting elements

(female) 25-pin for D-sub connection X41

16

Connector

Connector (male) 25-pin for D-sub connection X31

Data interface cable 3 m (9.9 ft), 25-pin for D-sub con-
complete nection X31, Id. Nr. 274 545-01

PP

Id. Nr. 249 154 ZY

Id. Nr. 245 739 ZY

ND 281V, Id. Nr. 322 353

100 ... 240 V

50 ... 60 Hz

Ground connection

Power switch

Data interface

X31 (V.24 /RS-232-C)

Input X1 for HEIDENHAIN
linear encoder

D-sub connection

X41 (EXT)

X1

Rear Panel

Connections X1, X31 and X41 comply with
recommendations in EN 50 178 for separation
from line power.

Encoder input X1

HEIDENHAIN flange socket, 9-pin
Input signals 11 µA

PP

Maximum encoder cable length 30 m (98.5 ft)
Maximum input frequency 100 kHz

RS-232-C/V.24 data interface (X31)

25-pin D-sub connection (female)

Switching inputs and outputs EXT (X41)

25-pin D-sub connection (male)

Accessories

ND 281A, Id. Nr. 283 481 ..

Data interface

X31 (V.24 /RS-232-C)

100 ... 240 V

50 ... 60 Hz

Power switch

Ground connection

NDP 281, Id. Nr. 289 214 ..

Data interface

D-sub
connection

X41 (EXT)

X1

Input X1 for HEIDENHAIN
linear encoder 11 µA

Input X1 for HEIDENHAIN
linear encoder 11 µA

PP

D-sub
connection

PP

Rear Panel, Accessories

Connecting elements

Connector

(female) 25-pin for D-sub connection X41

Id. Nr. 249 154 ZY

Connector (male) 25-pin for D-sub connection X31

Id. Nr. 245 739 ZY

Data interface cable 3 m (9.9 ft), 25-pin for D-sub con-
complete nection X31, Id. Nr. 274 545 01

X31 X41

100 ... 240 V

Power connection Ground connection

X1

17

15°

Mounting

Mounting

M4 screws are required for securing the ND 281 display unit
from below (see illustration at right).

The NDP 281 display unit is designed for panel mounting (see
“Dimensions” for the mounting dimensions).

ND 281 display units are stackable. Adhesive plug-in feet
(supplied with your unit) prevent the stacked units from being
moved out of place.

172 ± 0.2

6.77 ± .008"

Hole positions for mounting the ND display unit

140 ± 0.2

5.51 ± .008"

18

Alternatives of stacking the display units

Power Connection

Electric shock danger

Unplug the power cord before opening the
housing. Connect the grounding conductor.
Do not interrupt the grounding conductor.

Potential component damage

Do not engage or disengage any connections
unless the power is off. Only use original type
fuses.

To increase the noise immunity, it is
recommended that you attach the ground terminal
to, for example, the central ground point of the
machine.
(Minimum cross section 6 mm

Line voltage range: 100 Vac to 240 Vac
A voltage selector is therefore not necessary.

Minimum cross section of the power cord: 0.75 mm

ND 281

The rear panel of this unit contains a connecting jack for a
power cord with Euro connector (power cord supplied with
the delivery).

2.

)

2

X51

X 51

N

L1

Power Connection

NDP 281

The rear panel of this unit features a terminal (X51) for power
connection (see illustration to the right). Be careful to wire
the connecting cable with the correct polarity.

NDP 281: Terminal for connecting the power cord

19

Operating Parameters

Operating parameters allow you to modify the operating
characteristics of your ND display unit and define the
evaluation of the encoder signals.

Operating parameters are designated by:

• the letter P,

• a two-digit parameter number, and

• an abbreviation.

Example:

Operating Parameters

The factory settings of the operating parameters are
indicated in the parameter list (starting on page 22) in
boldface type.

Parameters consist of “user parameters” and “protected
operating parameters,” which can only be accessed by
entering a code number.

User parameters

User parameters are operating parameters that can be
changed without entering the code number:

P00 to P30, P50, P51, P79, P86

The functions of the individual user parameters are detailed in
the list of operating parameters (starting on page 22).

To access a user parameter ...
... after switching on the display:

While ENT ... CL is
displayed:

Display first user parameter.

MOD

... during operation:

Together:

Display first user parameter.

MOD

To go directly to a user parameter:

Together:

Press and hold CL while entering the first
digit of the parameter number (here, 1).

Enter the second digit of the parameter
number (here, 9).
The display shows the selected user
parameter.

20

Code number for changing protected operating
parameters

If you wish to change protected operating parameters, you
must first enter the code number 95 148:

➤➤

➤ Select the user parameter .

➤➤
➤➤

➤ Enter the code number 95 148.

➤➤
➤➤

➤ Confirm entry with ENT.

➤➤

Parameter P30 appears on the display. By paging through the
list of operating parameters you can display — and, if
necessary, change — each protected operating parameter and,
of course, each user parameter.

Once you have entered the code number, the
protected operating parameters remain accessible
until the display unit is switched off.

Functions for changing the operating parameters

Function Key

Page forward
in the list of operating parameters

Page backward
in the list of operating parameters

Reduce parameter value

Increase parameter value

Correct entry and
display parameter designations

Confirm change or numerical entry,
leave list of operating parameters

A changed parameter is stored as soon as you

• leave the list of operating parameters

or

• page forward or backward after the change.

MOD

Operating Parameters

21

List of Operating Parameters

Parameter Settings / Function

Enter code number 95 148
protected operating parameters

Unit of measurement

Display in millimeters
Display in inches

Sorting and tolerance checking

Sorting into classes ON
Sorting into classes OFF

Lower limit for sorting

List of Operating Parameters

Upper limit for sorting
Display for series of measurements

MIN MAX ACTL DIFF

Display stop for measured value output
Concurrent display, no display freeze;

the display value is the current actual
value

Frozen display; hold display until next
measured value output

Frozen/concurrent display; freeze display
as long as Pulse/Contact for measured
value output is present

to change

Parameter Settings / Function

Counting direction

Positive counting direction
with positive direction
of traverse

Negative counting direction
with positive direction
of traverse

Subdivision of the
encoder signals

400 / 320 / 256 / 200 / 160 / 128 / 100
80 / 64 / 50 / 40 / 20 / 10 / 8 / 5 / 4 / 2 / 1

0.8 / 0.5 / 0.4 / 0.2 / 0.1

Counting mode

0 - 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9
0 - 2 - 4 - 6 - 8
0 - 5

Decimal places

1 / 2 / 3 / 4 / 5 / 6
(up to 8 with display in inches)

22

Parameter Settings / Function

Linear error compensation

– 99 999,9 < P41 < + 99 999,9 [µm/m]

Factory setting: 0

Example: Determine input value for P41

Displayed length ...............................L

= 620.000 mm

d

Actual length (as determined,
for example, with the VM 101
comparator system

from HEIDENHAIN) ........................... L

= 619.877 mm

a

Difference ......................................... ∆L = L

Compensation factor k (= P41):
k = ∆L / L

= – 123 µm / 0.62 m ....... k = – 198,4 [µm/m]

d

Reference marks

One reference mark
Distance-coded with 500 • SP

(SP: signal period)
Distance-coded with 1000 • SP

(e.g. for HEIDENHAIN LS ...C)
Distance-coded with 2000 • SP
Distance-coded with 5000 • SP

Reference mark evaluation

Evaluate reference marks
Do not evaluate

reference marks

– Ld = – 124 µm

a

Parameter Settings / Function

Encoder monitoring

Monitoring not active

Contamination

Frequency

Contamination and frequency

Baud rate

110 / 150 / 300 / 600

1200 / 2400 / 4800 / 9600 baud

Additional blank lines for

data output

0

≤ P51 ≤ 99

Factory setting: 1

Trigger limit 1

Trigger limit 2

Value for datum point

Enter numerical value for

datum setting over switching input

or with ENT key

List of Operating Parameters

23

Parameter Settings / Function

Set display

No set/zero reset with CL/ENT
Zero reset with CL,

setting with ENT disabled
Zero reset with CL and

set with ENT to value
selected in P79

Message after switch-on

message

No message

External REF

List of Operating Parameters

REF over D-sub connection EXT
No REF over

D-sub connection EXT

First indicator after
pressing MOD

START PRINT

MIN ACTL MAX DIFF

24

Linear Encoders

Display step, signal period and subdivision for linear encoders

The ND 281 and NDP 181 display units are intended
for use with photoelectrical encoders with
sinusoidal signals — 11 µA

ND 281A, 11 µA
ND 281V, 1 V
NDP 281, 11 µA

Display step with linear encoders

The display step depends on the signal period of
the encoder and the subdivision of the encoder
signals.

You can select a specific display step by adapting
the following operating parameters:

• Subdivision (P32)

• Counting mode (P33)

• Decimal places (P38)

Example

Linear encoder with a signal period of 10 µm

Desired display step ................ 0.000 5 mm

Subdivision (P32) ..................... 20

Counting mode (P33) ............... 5

Decimal places (P38) ............... 4

: Id. Nr. 283 481 ..

PP

: Id. Nr. 322 353 ..

PP

: Id. Nr. 289 214 ..

PP

or 1 VPP.

PP

Signal period [µm]
Display step 2 4 10 20 40 100 200 12 800
[mm] [inches] P32: Subdivision

0.000 005 0.000 000 2 400 –––––– –

0.000 01 0.000 000 5 200 –––––– –

0.000 02 0.000 001 100 –––––– –

0.000 05 0.000 002 40 80 –– – – – –

0.000 1 0.000 005 20 40 100 200 ––– –

0.000 2 0.000 01 10 20 50 100 ––– –

0.000 5 0.000 02 4 8 20 40 80 –– –

0.001 0.000 05 2 4 10 20 40 100 ––

0.002 0.000 1 1 2 5 10 20 50 100 –

0.005 0.000 2 0.4 0.8 2 4 8 20 40 –

0.01 0.000 5 0.2 0.4 1 2 4 10 20 –

0.02 0.001 ––0.5 1 2 5 10 –

0.05 0.002 ––0.2 0.4 0.8 2 4 256

0.1 0.005 ––0.1 0.2 0.4 1 2 128

0.2 0.01 ––––––– 64

Linear Encoders

The tables on this page and on the next will help
you to select the appropriate parameter settings.

25

Parameter settings for HEIDENHAIN linear encoders with 11 µA

Model

CT

Linear Encoders

MT xx01
LIP 401A/401R

LF 103/103C
LF 401/401C
LIF 101/101C
LIP 501/501C
LIP 101

MT xx 10 single 0,0005

LS 303/303C
LS 603/603C

26

Reference
marks

Signal period

[µm]

P 43

2

single 0,0005

-/single

Millimeters Inches

Display
step [mm]

0,0002
0,0001
0,00005

Recommended only for LIP 401

0,00002
0,00001
0,000005

4

single/5000 0,001

0,0005
0,0002
0,0001

single

0,00005

Recommended only for LIP 101

0,00002
0,00001

0,0002
0,0001

20 single/1000 0,01

0,005

signals

PP

Subdi-

vision

Count

P 32 P 33 P 38

4
10
20
40

100
200
400

4
8
20
40
80

200
40021

20
50
100

2
4

5
2
1
5

2
1
5

1
5
2
1
5

5
2
1

1
5

Decimal

4
4
4
5

5
5
6

3
4
4
4
5

5
5

4
4
4

2
3

Display
step [inch]

places

0,00002
0,00001
0,000005
0,000002

0,000001
0,0000005
0,0000002

0,00005
0,00002
0,00001
0,000005
0,000002

0,000001
0,0000005

0,00002
0,00001
0,000005

0,0005
0,0002

Subdi-

vision

Count

P 32 P 33 P 38

4
10
20
40

100
200
400

4
8
20
40
80

200
40015

20
50
100

2
4

2
1
5
2

1
5
2

5
2
1
5
2

2
1
5

5
2

Decimal

5
5
6
6

6
7
7

5
5
5
6
6

6
7

5
5
6

4
4

places

Parameter settings for HEIDNHAIN linear encoders with 11 µAPP signals (continued)

Signal period

Reference
marks

[µm]

P 43

single/1000

-

Millimeters Inches

Display
step [mm]

0,001
0,0005

0,005
0,002
0,001
0,0005

Subdi-

vision

Count

P 32 P 33 P 38

20
40

8
20
40
80

1
5

5
2
1
5

3
4

3
3
3
4

Decimal

Display
step [inch]

places

0,00005
0,00002

0,0002
0,0001
0,00005
0,00002

Model

LS 106/106C
LS 406/406C
LS 706/706C
ST 1201

LB 302/302C
LIDA 10x/10xC

20

40 single/2000

Recommended only for LB 302

0,0002
0,0001

LB 301/301C 100 single/1000 0,005

0,002
0,001

LIM 102 12800 single 0,1

0,05

Example

Your encoder: MT 101
Desired display step: 0.0005 mm (0,5 µm)

Parameter settings: P01 = mm, P43 = single, P32 = 20, P33 = 5, P38 = 4

200
40021

20
50
100

128
25615

4
4

5
2
1

3
3
3

1
2

0,000001
0,0000005

0,0002
0,0001
0,00005

0,005
0,002

Subdi-

vision

Count

P 32 P 33 P 38

20
40

8
20
40
80

200
40015

20
50
100

128
25652

5
2

2
1
5
2

2
1
5

Decimal

5
5

4
4
5
5

5
6

4
4
5

3
3

places

Linear Encoders

27

Parameter settings for HEIDENHAIN linear encoders with 1 VPP signals

Model

LIP 382 0,128 - 0,000002

Linear Encoders

MT xx81
LIP 481A/481R

LF 183/183C
LF 481/481C
LIF 181/181C
LIP 581/581C
VM 182

LS 186/186C
LS 486/486C
ST 1281

2single

4

20

Reference
marks

Signal period

[µm]

P 43

-/single

single/5000 0,001

-

single/1000 0,001

-

Millimeters Inches

Display
step [mm[

Subdi-

vision

Count

P 32 P 33 P 38

0,0000016412821
0,0005

0,0002
0,0001
0,00005

4
10
20
40

5
2
1
5

Recommended only for LIP 401

0,00002
0,00001
0,000005

0,0005
0,0002
0,0001
0,00005

100
200
400

4
8
20
40
80

2
1
5

1
5
2
1
5

Recommended only for VM 182

0,00002
0,00001

0,0005

200
40021

20
40

1
5

6
6

4
4
4
5

5
5
6

3
4
4
4
5

5
5

3
4

Display
step [inch]

Decimal

places

0,0000001
0,000000056412815

0,00002
0,00001
0,000005
0,000002

0,000001
0,0000005
0,0000002

0,00005
0,00002
0,00001
0,000005
0,000002

0,000001
0,0000005

0,00005
0,00002

Subdi-

vision

Count

P 32 P 33 P 38

4
10
20
40

100
200
400

4
8
20
40
80

200
40015

20
40

2
1
5
2

1
5
2

5
2
1
5
2

5
2

Decimal

7
8

5
5
6
6

6
7
7

5
5
5
6
6

6
7

5
5

places

28

Parameter settings for HEIDENHAIN linear encoders with 1 VPP signals (continued)

Signal period

[µm]

Reference
marks

P 43

Millimeters Inches

Display
step [mm]

0,005
0,002
0,001
0,0005

Subdi-

vision

Count

P 32 P 33 P 38

8
20
40
80

5
2
1
5

3
3
3
4

Decimal

Display
step [inch]

places

0,0002
0,0001
0,00005
0,00002

Model

LB 382/382C
LIDA 18x/18xC

40 single/2000

Recommended only for LB 382

0,0002
0,0001

LB 381/381C 100 single/1000 0,005

0,002
0,001

Example

Your encoder: LS 186 C
Desired display step: 0.001 mm (1 µm)

Parameter settings: P01 = mm, P43 = 1 000, P32 = 20, P33 = 1, P38 = 3

200
40021

20
50
100

4
4

5
2
1

3
3
3

0,00001
0,000005

0,0002
0,0001
0,00005

Subdi-

vision

Count

P 32 P 33 P 38

8
20
40
80

200
40015

20
50
100

2
1
5
2

2
1
5

Decimal

4
4
5
5

5
6

4
4
5

places

Linear Encoders

29

RS-232-C/V.24 Interface (X31)

The RS-232-C/V.24 interface (X31) of your display unit
enables you to output measured data in ASCII format, for
example to a printer or PC.

Connecting cable

You can use a connecting cable with full wiring (figure at
upper right) or simplified wiring (below right). A cable with full
wiring is available from HEIDENHAIN (Id. Nr. 274 545 ...). On
this type of cable, pin 6 and pin 8 are additionally connected
over a jumper.

Maximum cable length: 20 m (66 ft)

RS-232-C/V.24 Interface (X31)

Full wiring

ND

CHASSIS

SIGNAL

ND

CHASSIS

TXD
RXD
RTS
CTS
DSR
GND
DTR

TXD
RXD
RTS
CTS
DSR
GNDSIGNAL
DTR

2
3
4
5
6
7

20

1GND
2
3
4
5
6
7

20

11GND
2
3
4
5
6
7

20

1 GND
2
3
4
5
6
7

20

SIGNAL

CHASSIS

TXD
RXD
RTS
CTS
DSR
GND
DTR

TXD
RXD
RTS
CTS
DSR
GNDSIGNAL
DTR

GND

CHASSIS

30

Simplified wiring

Pin layout RS-232-C/V.24 (X31)

Data format and control characters

Pin Signal Assignment

1 CHASSIS GND Chassis ground
2 TXD Transmitted data
3 RXD Received data
4 RTS Request to send
5 CTS Clear to send
6 DSR Data set ready
7 SIGN. GND Signal ground
8 to 19 –

Not assigned

20 DTR Data terminal ready
21 to 25 –

Not assigned

Levels for TXD and RXD

Logic level Voltage level

Active – 3 V to – 15 V
Not active + 3 V to +15 V

Levels for RTS, CTS, DSR and DTR

Logic level Voltage level

Active + 3 V to + 15 V
Not active – 3 V to – 15 V

Data format 1 start bit

7 data bits
Even parity bit
2 stop bits

Control characters Call measured value: STX (Ctrl B)

Interrupt DC3 (Ctrl S)
Continue DC1 (Ctrl Q)

Interrogate error message: ENQ (Ctrl E)

Example: Data sequence during measured value output

Measured value = – 5.23 mm
The measured value is within the sorting limits ( = ) and is the
current value ( A ) of a series of measurements.

Measured value output

– 5 . 2 3 = A < C R > < L F >

12 3456 7 8

1

Algebraic sign

2

Numerical value with decimal point (10 characters on
the whole, leading zeros are output as blank spaces.)

3

Blank space

4

Unit: Blank space = mm; " = inch; ? = fault

5

Sorting status (<, >, =; ? if P18 > P19)
or blank space

6

Series of measurements
(S = MIN; A = ACTL; G = MAX; D = DIFF)
or blank space

7

CR (carriage return)

8

LF (line feed)

RS-232-C/V.24 Interface (X31)

31

Operating parameters for measured value output

Parameter Function

Baud rate
Number of additional blank lines for

measured value output

Display freeze during measured value output

In operating parameter P23, you can specify how the
measured value output signal will affect the display unit.

Display freeze during measured value outputP23

Concurrent display, no display freeze:

RS-232-C/V.24 Interface (X31)

The display value is the current measured value
Frozen display: Display is stopped

(frozen) and updated by every
measured value output signal

Frozen/concurrent display: Display is
frozen as long as a measured value output
signal is present

To output measured values with the PRINT function:

➤➤

➤ Press MOD repeatedly,

➤➤

until the indicator PRINT blinks.

➤➤

➤ Start measured value output with ENT.

➤➤

Duration of measured value transfer

187 + (11 • number of blank lines)

t

= [s]

D

Indicator preselection

Operating parameter P86 allows you to define which indicator
is displayed first when MOD is pressed.

baud rate

32

Measured value output after signal through the “Contact”
or “Pulse” inputs

To start measured value output through the EXT interface
(X41) you can either:

➤➤

➤ Close the “Contact” input (pin 23 on X41) against 0 V,

➤➤

for example with a simple switch (make contact);

or

➤➤

➤ Close the “Pulse” input (pin 22 on X41) against 0 V,

➤➤

for example by triggering the input with a TTL logic
device (such as SN74LSxx).

EXT(X41)

Pin 23

Pin 1(0V)

EXT(X41)

Pin 22

Characteristic times for measured value output

Process Time

Minimum duration of “Contact” signal te ≥ 7 ms
Minimum duration of “Pulse” signal te ≥ 1.5 µs
Storage delay after “Contact” t1 ≤ 5 ms
Storage delay after “Pulse” t1 ≤ 1 µs
Measured value output after t2 ≤ 57 ms
Regeneration time t3 ≥ 0

The time for measured value output (t

2

longest during a DIFF series of measurements.

Duration of measured value transfer

187 + (11 • number of blank lines)

= [s]

t

D

baud rate

) is the

Pin 1(0V)

Triggering the “Contact” and “Pulse” inputs at D-sub connection
EXT (X41)

t

e

t

1

t

2

t

D

Signal transit times for measured value output after “Pulse” or “Contact”

t

e

t

3

RS-232-C/V.24 Interface (X31)

33

t

1

t

2

Ctrl B

t

D

t

3

Ctrl B

Measured value output after signal “STX” (Ctrl B)

If the display unit receives the control character STX (Ctrl B)
over the RS-232-C/V.24 interface (X31), it outputs the current
measured value over the interface.

➤➤

➤ Transfer the control character Ctrl B over the RXD line of

➤➤

the RS-232-C/V.24 interface (X31).

Characteristic times for measured value output

Process Time

Storage delay t1 ≤ 1ms
Measured value output after t2 ≤ 22 ms
Regeneration time t3 ≥ 0

RS-232-C/V.24 Interface (X31)

These times are prolonged if functions are active
(for example, series of measurements with DIFF
value display).

Duration of measured value transfer

187 + (11 • number of blank lines)

tD = [s]

baud rate

10 L%=17
20 CLS
30 PRINT "V.24/RS-232-C"
40 OPEN "COM1:9600,E,7" AS#1
50 PRINT #1, CHR$ (2);
60 IF INKEY$<>""THEN 130
70 C%=LOC(1)
80 IF C%<L%THEN 60
90 X$=INPUT$(L%,#1)
100 LOCATE 9,1
110 PRINT X$;
120 GOTO 50
130 END

BASIC program for measured value output with “Ctrl B”

34

Signal transit times for measured value output after “Ctrl B”

Switching Inputs and Outputs EXT (X41)

Inputs at D-sub connection EXT (X41)

Danger to internal components!

Voltage sources for external circuitry must conform
to the recommendations in EN 50 178 for
low-voltage electrical separation. Connect
inductive loads only with a quenching diode
parallel to the inductance.

Only use shielded cable!

Connect the shield to the connector housing.

Outputs at D-sub connection EXT (X41)

Pin Function

14 Display value is zero
15 Measured value ≥ trigger limit A1 (P62)
16 Measured value ≥ trigger limit A2 (P63)
17 Measured value < lower sorting limit (P18)
18 Measured value > upper sorting limit (P19)
19 Error (see “Error Messages”)

Pin Function

1, 10 0 V
2 Reset display to zero, clear error message
3 Set display to the value selected in P79
4 Ignore reference mark signals
5 Start series of measurements
6 Externally select display value for series of

measurements
7 Display MIN value of series of measurements
8 Display MAX value of series of measurements
9 Display difference MAX – MIN
22 Pulse: Output measured value
23 Contact: Output measured value
25 Enable or disable REF mode

(current REF status is changed)
12, 13, 24
11, 20, 21

Special case: Display current measured value ACTL

If you wish to display the current measured value ACTL of a
series of measurements, note for inputs 7, 8 and 9:
Either none or more than one of these inputs must be active.

Do not assign

Vacant

Switching Inputs and Outputs EXT (X41)

35

Inputs

Outputs

Input signals

Internal pull-up resistor 1 kΩ, active with low level
Trigger by making contact against 0 V or

by low level signal over TTL logic device
Delay for set/zero reset: td ≤ 2ms
Minimum pulse duration for all signals: t

The duration of t

is prolonged if functions are

min

≥ 22 ms

min

active (for example, series of measurements with
DIFF value display).

Signal level of inputs

Status Level

High + 3.9 V ≤ U ≤ + 15 V
Low – 0.5 V ≤ U ≤ + 0.9 V; I ≤ 6 mA

Switching Inputs and Outputs EXT (X41)

E

0V

E

0V

t

t

min

36

≥ 22 ms

min

Output signals

Open collector outputs, active with low level
Delay until signal output: td ≤ 22 ms

Signal duration of zero signal, trigger limit A1, A2: t0 ≥ 180 ms

The duration of td is prolonged if functions are
active (for example, series of measurements with
DIFF value display).

Signal level of outputs

Status Level

High U ≤ + 32 V; I ≤ 10 µA
Low U ≤ + 0.4 V; I ≤ 100 mA

I ≤ 100 mA

+ UB ≤ 32 V

C

B

U

CE

E

Pin 1.10

0 V

Setting and zero resetting the display

With an external signal, you can set the display to the value
selected in parameter P79 (pin 3) or reset each axis to zero (pin 2).

Enabling and disabling REF mode

Operating parameter P85 allows you to activate the input
(pin 25) which will be used for setting the display externally
to REF mode when the unit is switched on or when the
power is restored after an interruption. The next signal
deactivates REF mode again (switchover function).

Ignoring reference mark signals

If this input (pin 4) is active, the display will ignore all
reference mark signals. A typical application of this function is
for measuring lengths with a rotary encoder and spindle; in
this case, a cam switch releases the reference mark signal at
a preset position.

Externally selecting MIN/MAX
Starting a series of measurements
Switching the display between MIN/MAX/DIFF/ACTL

You can activate the operating mode for finding minimum and
maximum values from a series of measurements with an ex­ternal signal (pin 6, low-level signal must be present con­tinuously). The setting selected with MOD or operating pa­rameter P21 is disabled. You can switch to MIN/MAX/DIFF/
ACTL display (pins 7, 8, 9, low-level signal must be present
continuously) and START (pin 5, Pulse) a new series of meas­urements only by external signal over the switching inputs.

Switching Inputs EXT (X41)

37

Switching signals

As soon as the trigger points defined in parameters are
reached, the corresponding outputs (pins 15,16) are activated.
You can set up to two trigger points. The switching point
“zero” has a separate output (see “Zero crossover”).

Signals for sorting and tolerance checking

Output

Path

Switching point

If the sorting limits defined in parameters are exceeded, the
corresponding outputs (pins 17, 18) are activated.

Signals Operating parameters Pin

Switching signals P62, switching limit 1
15 P63, switching limit 2

Switching Inputs EXT (X41)

16

Sorting signals P18, lower sorting limit 17

P19, upper sorting limit 18

Zero crossover

The display value “zero” activates the corresponding output
(pin 14). Minimum signal duration is 180 ms.

38

Measured value < Lower sorting limit

Measured value > Upper
sorting limit

Path

Lower limit Upper limit

Path

Weg

5

t

Pin 15

(A1)

t

d

t

v

t

t

d

v

t

Time curve of a signal at pin 15 for trigger limit (A1) = 5 mm , td≤ 22 ms

Switching signal for errors

The display unit permanently monitors functions such as
measuring signal, input frequency, and data output, and
displays an error message if it detects an error.

If errors occur that seriously influence measurement or data
output, the display unit activates a switching output. This
feature allows monitoring of automated processes.

ERROR xx

Switching Outputs EXT (X41)

39

Operating Mode for Displaying Distance-To-Go

Function of switching outputs A1 and A2

Normally, the display shows the actual position of the en­coder. However, it is often more helpful to display the remain­ing distance to an entered nominal position — especially when
you are using the display unit for machine tools and automa­tion purposes. You can then position simply by traversing to
display value zero.

You can access the distance-to-go display by entering the

code number 246 582.

Display Meaning

Distance-to-go display not active
Distance-to-go display active

“Traversing to zero” with distance-to-go display

➤➤

➤ Select datum point 2.

➤➤
➤➤

➤ Enter the nominal position.

➤➤
➤ Move the axis until the display value is zero.

Operating Mode for Displaying Distance-To-Go

In the operating mode for displaying distance-to-go, switching
outputs A1 (pin 15) and A2 (pin 16) have a different function:
they are symmetrical to the display value zero. For example,
if a switching point of 10 mm is entered in P62, output A1
switches at both +10 mm and –10 mm. The figure below
shows output signal A1 when approaching zero from the
negative direction.

–10

Ð10

0

+10

Path

Pin 15

(A1)

t

d1

t

v1

t

d2

t

v2

t

Time curve of a signal for switching limit (A1) = 10 mm , t
t

≤ 180 ms

d2

≤ 22 ms,

d1

40

Specifications

Housing ND 281

Bench-top design,
cast-metal housing
239 • 84.6 • 224 mm (W • H • D)

NDP 281

For panel mounting using supplied
mounting frame,
cast-metal housing
281 • 110 • 196 mm (W • H • D)

Operating temperature 0° to 45° C (32° to 113° F)
Storage temperature –30° C to 70° C (–22° to 158° F)
Weight Approx. 1.5 kg
Relative humidity < 75 % annual average

< 90 % in rare cases

Power supply Primary-clocked power supply

100 V to 240 V (–15% to +10%)
48 Hz to 62 Hz

Line fuse F 1 A inside the housing
Power consumption Typ. 8 W
Electromagnetic

compatibility Class B according to EN 55022

Noise immunity As per IEC 801-4, intensity 4
Protection IP40 according to IEC 529
Encoder inputs For encoders with sinusoidal

output signals (11 µA
Reference mark evaluation for
distance-coded and single
reference marks

Input frequency ND 281 A/NDP 281 11 µA

100 kHz max. for 30 m cable length
ND 281V 1 V
300 kHz max. for 60 m cable length

Display step Adjustable

(see “Linear Encoders”)

Datum points Two
Functions • Series of measurements

• Sorting and tolerance checking

• Switching and sorting signals

• Set display and reset display to
zero with external signal

• Measured value output

RS-232-C/V.24 Baud rates:
Interface 110, 150, 300, 600, 1200, 2400,

4800, 9600 baud

/1 VPP);

PP

PP

PP

:

Specifications

:

41

ND 281: Dimensions in mm/inches

°

15

X

84.6

3.33"

Specifications

6

.24"

33.5

1.37"

325

12.8"

42

HEIDENHAIN

M4 x 6
M4 x .24"

X

172 ± 0.2

6.77" ± .008"

239

9.41"

35

140 ± 0.2

1.43"

5.51" ± .008"

224

8.82"

X31

X1

ND 281A Id. Nr. 283 481 ..

X

X31

X1

ND 281V Id. Nr. 322 353 ..

X41

X41

NDP 281: Dimensions in mm/inches

6

.24"

110

4.33"

98±0.2

3.858"±.008"

6

.24"

281

11.06"

269±0.2

10.59"±.008"

X

297

11.7"
196

7.72"

HEIDENHAIN

¯5.5

X

X1

86

3.39"

.22"

IA

D

X51

X31 X41

257

10.12"

Id.-Nr. 289 214 ..

Specifications

2

.08"

1

.04"

F

259+0.5 x 88+0.5

10.2"+.02" x 3.46"+.02"

Opening for panel mounting F

43

DR. JOHANNES HEIDENHAIN GmbH

Dr.-Johannes-Heidenhain-Straße 5

83301 Traunreut, Germany

{ +49/8669/31-0

| +49/8669/5061

e-mail: [e-mail]

{ Service
{ TNC-Service
|+49/8669/98

e-mail: [e-mail]

http://www.heidenhain.de

HEIDENHAIN (G.B.) LimitedHEIDENHAIN (G.B.) Limited

HEIDENHAIN (G.B.) Limited

HEIDENHAIN (G.B.) LimitedHEIDENHAIN (G.B.) Limited
200 London Road, Burgess Hill
West Sussex RH15 9RD, Great Britain

{ (01444) 24 77 11
| (0 1444) 87 00 24

+49/8669/
+49/8669/

99

31-12 72
31-14 46

44

284 251 26 · SW 246 181 01 · 3 · 5/97 · H · Printed in Germany · Subject to change without notice