Fagor Prokit 1, Lathe Dro T4, Prokit 4, Prokit 5, Lathe Dro T5 User Manual

Linear and angular

encoders

standard series

Technology

An encoder measures the actual machine
position without the effect of any
mechanical inaccuracies. Machine errors
induced due to mechanical inaccuracies are
eliminated as the encoder is attached to the
machine guide ways and hence provides the
actual machine position to the controller.
Some of the potential sources of such errors
in a machine tool such as lead screw pitch,
certain amount of backlash and thermal
behavior can be minimized using these
encoders.

Measuring methods

Fagor uses two measuring methods in their incremental
encoders:

• Graduated glass: Linear encoders with a measuring
length of up to 3
light from the LED goes through an engraved glass and a
reticule before reaching the receiving photo diodes. The
period of the generated electrical signals is the same as the
graduation pitch.

• Graduated steel: Linear encoders with a measuring length
over 3

040 mm use auto imaging principle which uses
diffuse light reflected from the graduated steel tape. This
optical reading system consists of a LED as a light source,
a mesh that creates the image and a monolithic photo
detector element in the image plane, which is specially
designed and patented by Fagor.

040 mm use optical transmission. The

Types of incremental encoders

• Linear encoder: Suitable for applications on milling,
turning, boring mills, grinding machines for feedrates of up
to 120 m/min and vibration levels up to 10 g.

• Rotary encoder: Used as measurement device for rotary
axis, angular speed and also for linear movements for
mechanisms like lead screws etc. They are widely used
in machine tools, wood working equipment, robots and
material handlers etc.

Enclosed design

The graduated scale in a linear encoder is protected by the
enclosed aluminum profile. The highly durable sealing lips
protect the encoder from industrial contaminants and liquid
splashes as the reader head moves along the profile. The
reader head movement in complete synchronization captures
and transmits the position and movement of the machine.
The reader head moves along the graduated scale on linear
bearings minimizing the friction. For enhanced protection
against contamination both ends of the encoder and also the
reader head can be connected to pressurized air.

Graduated glass linear encoder

LED’s Graduated glassGrid

Etching Receiving photo-diodes

Reference marks

Graduated steel linear encoder

Graduated steel Grid LED’s

2

Etching

Reference marks

Graduated glass rotary encoder

Receiving photo-diodes

Graduated glass disk

Receiving photo-diodes

Grid

Flat convex lens

LED

Reference marks

Graduated glass

Cursor

Sealing lips

Reader head

Air intake at both ends

Incremental

Distance-coded

Air intake on the reader head

Linear encoder

Series

F 50.1 50.2 50.3 100
C, M 10.02 10.04 10.06 20

Distances

a b c d

Reference signals (I0)

The reference signal is a specially etched mark along the
graduated glass, which when scanned generates a pulse
signal. They are used to set/recover the machine zero
position and avoid possible errors after powering up the DRO
or CNC system.

Fagor provides two different types of reference marks

• Incremental: The reference signal is synchronized with the
feedback pulses to ensure perfect measuring repeatability.

Linear: One every 50 mm of travel.
Rotary: One signal per turn.

• Distance-coded: Each distance coded reference signal
is separated from the next signal a different distance
according to predefined mathematical function. The actual
position value after power up is restored by moving through
two consecutive reference signals. This is very useful for
long travel axes as the movement needed to recover actual
position is minimum.

I

:

0

incremental

Rotary encoder

I

0

Pitch

Zero position

3

E N C O D E R S

Electrical output signals

D i f fe re nt ia l T TL

These are complementary signals in compliance with the
EIA standard RS-422. This characteristic together with a
line termination of 120 Ω, twisted pair, and an overall shield
provide greater immunity to electromagnetic noise caused by
the surrounding environment.

Characteristics

I

Signals A, /A, B, /B,

Signal level VH ≥ 2.5V IH= 20 mA

VL ≤ 0.5V IL= 20 mA
With 1 m cable

90º reference signal (

I

) Synchronized with A and B

0

Switching time t+/t-< 30ns

With 1 m cable

T period according to model

Max. cable length 50 meters

Load impedance Z

o= 120 Ω between differential

0

, / I

0

N o di ff er en t i a l TT L

Characteristics

Signals A, B, /

Signal level A, B, I

90º reference signal (

0

I

) Synchronized with A and B

0

Switching time t+/t-< 30ns

T period according to model

Max. cable length 20 meters

Voltage drop across cable

The voltage requirements for a TTL encoder are 5V ±5%.
A simple formula described below, may be used to calculate
the maximum cable length depending on the cross section
diameter of the supply cable:

L

max = (VCC-4,5)* 500 / (ZCABLE/Km* IMAX)

Example

V

cc = 5V, IMAX = 0.2 Amp (with 120 Ω load)

2

Z (1 mm

Z (0.5 mm

Z (0.25 mm

Z (0.14 mm

) = 16.6 Ω/Km (Lmax= 75 m)

2

) = 32 Ω/Km (Lmax= 39 m)

2

) = 66 Ω/Km (Lmax= 19 m)

2

) = 132 Ω/Km (Lmax= 9 m)

I

0

VH ≥ 3.5 V IH = 4 mA
VL ≤ 0.4 V IL = 4 mA
with 1 m cable

with 1 m cable

Cable length

4

meters

D i f fe re nt ia l 1 V pp

They are complementary sinusoidal signals whose differential
value is 1 Vpp centered on V
with a line termination of 120 Ω, twisted pair, and an overall
shield provide greater immunity against electromagnetic noise
caused by their surrounding environment.

Characteristics

Signals A, /A, B, /B,

VApp 1 V +20%, -40%

V

Bpp 1 V +20%, -40%

DC offset 2.5 V ±

Signal period according to model

Max. cable length 150 meters

A, B centered: |V

A&B relationship V

1-V2| / 2 Vpp ≤

App / VBpp 0.8

A&B phase shift: 90°

I

amplitude: VI0 0.2 ÷ 0.8 V

0

I

width: L + R I0_min: 180°

0

I

synchronism: L, R 180º ± 90º

0

cc/2. This characteristic together

I

0, / I0

0.5 V

0.065

÷

1.25

±

10°

I

_typ: 360°

0

I

_max: 540°

0

Cable length

meters

0.14 mm

0.09 mm

Voltage drop across cable

The voltage requirements for a 1 Vpp encoder are 5V ±10%.
A simple formula may be used to calculate the maximum
cable length depending on the cross section diameter of the
supply cables.

L

max = (VCC-4,5)* 500 / (ZCABLE/Km* IMAX)

Example

V

cc = 5V, IMAX= 0.1 Amp

2

Z (1 mm

Z (0.5 mm

Z (0.25 mm

Z (0.14 mm

) = 16.6 Ω/Km (Lmax= 150 m)

2

) = 32 Ω/Km (Lmax= 78 m)

2

) = 66 Ω/Km (Lmax= 37 m)

2

) = 132 Ω/ Km (Lmax= 18 m)

1 Vpp signal damping due to the cable
section

2

2

Besides attenuation due to signal frequency, there is another
signal attenuation caused by the section of the cable
connected to the encoder.

Cable length

meters

5

I N C R E M E N T A L

F series

L I N E A R

Gene ral s pecif icati on

Measurement By means of stainless steel linear encoder

Steel tape accuracy ± 5 µm

Maximum speed 120 m/min.

Maximum vibration 10 g

Moving thrust < 5 N

Operating
temperature

Storage temperature -20 ºC...70 ºC

Weight 1.50 kg + 4 kg/m

Relative humidity 20...80%

Protection

Reader head With detachable cable connector

with 100 μm etching pitch

0 ºC...50 ºC

IP 53 (standard)
IP 64 (DIN 40050) using pressurized air in
linear encoders at 0.8 ± 0.2 bar

Especially designed for machines with longer travels and
they are available up to 30 m in length. In the incremental
model the reference marks are 50 mm apart and distance
coded model is also available. Both models come with a
detachable cable connectors in the reader head. The steel
tape graduation pitch is 100 μm. For measuring lengths over
4040 mm the encoder is supplied in multiple sections and is
assembled together at the time of installation.

Measuring lengths in millimeters

• Measuring lengths from 440 mm to 30 m in 200 mm

increments. Contact Fagor Automation for custom length
scales over 30 m.

Spec ific chara cteri stics

FT

FOT

Resolution 5 µm 1 µm Up to 0.1 µm

Reference marks (

Output signals

T period of output
signals

Limit frequency 100 kHz 500 kHz 20 kHz

Maximum cable length 20 m 50 m 150 m

Supply voltage 5 V ±5% ,100 mA (without load)

I

)

0

FOT, FOX, FOP: Distance-coded

TTL

20 µm 4 µm 100 µm

6

FX

FOX

FT, FX, FP: every 50 mm

TTL differential

5 V ± 10%, < 100 mA

(without load)

FP

FOP

I

0

1 Vpp