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SR21-IR / SR21-RG 

INSTRUCTION MANUAL 

 

 

CONTROLS

 

 

OUTPUT LED (YELLOW)

 

The yellow LED ON indicates output activation. 

READY/ERROR LED (RED/GREEN) 

The green LED continuously ON indicates a normal operating condition. Refer to the “SETTING” 
paragraph for the correct setting phase indications. 
The red LED continuously ON or blinking indicates an error status. 
Refer to “ERROR INDICATIONS” paragraph for the correct indications during the different functioning 
phases. 

AUTO-SET PUSH-BUTTON 

Activates the different setting modes using the READY/ERROR LED indications. 
The pressure on the AUTO-SET push-button can be “brief” when pressed for at least 3 sec., or “long” 
when pressed longer. 
Refer to “SETTING” paragraph for operating mode indications. 
 

                 

 

 

DIMENSIONS

 

 

 

 

 

mm

16

7.5

n°2  M4x8

12

Ø4.25

90

2

4

4

18

18

6

M8

LOCK SCREW

50

7.5

9

9

20

8

26

20

97.5

26

PO
WE
R

 S

U

PP

LY

OU
TP

U

T

PUSH-BUTTON

LEDS

 

NOTE 

To install the sensor using the connector positioned at 90°, unscrew the blocking screw and rotate the 
fixing block in an anti-clockwise direction. At the end rescrew the blocking screw. 

 

CONNECTIONS 

 

M8 connector 
 
 

 

 
 

 

TECHNICAL DATA 

 

Power supply: 

10 … 30 Vdc; 

reverse polarity protection 

Ripple: 

2 Vpp max. 

Consumption 
(output current excluded): 

55 mA max. 

Outputs: 

NPN and PNP on different poles; 

pull up/down resistance= 33 K

 

Output current: 

100 mA max. 

short-circuit protection 

Output saturation voltage: 

2 V max. with NPN 
2 V max. with PNP 

(values at maximum output current) 

Response time: 

20 µs max. 

Switching frequency: 

25 kHz max. 

T rise: 

1 µs (NPN; R = 1 K

 

120 µs (NPN; C = 4.7 nF) 

33 K

 pull-up internal resistance 

T fall: 

1 µs (PNP; R = 1 K

 

120 µs (PNP; C = 4.7 nF) 

pull-down internal resistance 33 K

 

Humidity: 

35 … 85% rH non-condensing 

Indicators: 

Bicolour READY/ERROR LED (green/red) 

OUT LED (yellow) 

Setting: AUTO-SET 

push-button 

Data retention: 

EEPROM non volatile memory 

Operating temperature: 

-20 … 60°C 

Storage temperature: 

-20 … 70°C 

Emssion frequency: 

Modulated light at 50 kHz 

±

10% 

Emission type: 

infrared 880 nm 

visible red/green (633 nm/570 nm) 

Ambient light rejection: 

EN 60947-5-2 

Slot width: 

2 mm 

Detectable object limits: 

Min. 0.5mm width 

Housing material: 

ZAMA 

Lens material: 

glass 

Mechanical protection: 

IP65 

Connections: 

M8 4-pole connector 

Weight: 115 

g. 

 
 

SETTING 

 

Static setting (MANUAL) 

Recommended in presence of transparent irregular profiles and requires a separate acquisition of the 
label and of the support with manual positioning.  
The best result is obtained acquiring the most transparent area of the label and the most opaque area of 
the support. 

Setting steps: 

1) With LED continuously ON, position the label in the sensor slot if the output has to be activated in 

correspondence of the label (NORMAL output), or position the support if the output has to be 
activated in correspondence of the support (INVERTED output). Use the specific references for 
centring. 

2) Briefly press AUTO-SET. The green and yellow LEDs turn OFF. The object acquisition phase begins. 

The object must not be moved until the green LED doesn’t blink rapidly. 

3) When the green LED blinks postion the second object (support or label) in the sensor slot using the 

specific references for centring. 

4) Briefly press AUTO-SET. The green LED turns OFF. The detection of the second object begins. The 

object must not be moved until the green LED doesn’t turn ON continuously. 

5) The green READY LED continuously ON indicates that the sensor has detected a sufficient contrast 

between the label and the support. The sensor can function with the new setting. A different indication 
signals an error due to insufficient contrast. 

 

Static setting of only the support (MANUAL) 

Recommended in presence of less critical conditions where the label is totally opaque and the output 
has to be activated in correspondence of the label. The detection of only the support has be carried-out 
with manual positioning. 

Setting steps: 

1) With LED continuously ON, position the support in the sensor slot, slot using the specific references 

for centring. 

2) Briefly press AUTO-SET. The green and yellow LEDs turn OFF. The support acquisition phase 

begins. The support must not be moved until the green LED doesn’t blink rapidly 

3) When the green LED blinks, press AUTO-SET until the green LED blinks rapidly three times. Release 

the push-button. 

4) The green READY LED continuously ON indicates that the sensor has detected a sufficient support 

transparency degree. The sensor can function with the new setting, activating the output in 
correspondence of the label (NORMAL output). A different indication signals an error due to insuffient 
transparency. 

 

Dynamic setting with NORMAL or INVERTED output 

The programming has to be carried-out during normal movement of the label ribbon inside the sensor 
slot. Recommended for labels and supports with a rather uniform transparency degree. 

Setting steps:

 

1) With green LED continuously ON, start the movement of the label ribbon in the sensor slot. 
2) Press AUTO-SET until the green LED blink slowly. 
3) Release the push-button. The sensor acquires the transparency degree of both the moving labels and 

support in approximately 2 sec. cycles. Leave the sensor in this acquisition phase for the time 
necessary to guarantee the detection of the major number of points possible. The duration depends 
on the ribbon speed and dimensions of the labels and support.  

4) Setting with NORMAL output: briefly press AUTO-SET. The green READY LED continuously ON 

indicates that the sensor has detected a sufficient contrast between the label and support. The sensor 
begins to function with the new setting and the output is activated in correspondence of the label. A 
different indication signals an error due to insufficient contrast. 

5) Setting with INVERTED output: press AUTO-SET until the green LED blinks rapidly three times. 

Release the pus-button. The green READY LED continuously ON indicates that the sensor has 
detected a sufficient contrast between the label and the support. The sensor begins to function wth 
the new setting and the output is activated in correspondence of the support. A different indication 
signals an error due to insufficient contrast. 

 
 

ERROR INDICATIONS 

 

READY/ERROR LED blinking with slow red and green alternation: indicates that the setting (static or 
dynamic) has failed due to insufficient transparency or contrast between label and support. In this case 
the sensor maintains the previous setting and returns to normal functioning pressing and releasing 
AUTO-SET. 
READY/ERROR LED red blinking at average speed: during normal functioning and only with active 
output, indicates a short-circuit or overload of the outputs or insufficient power supply. The indication 
disappears when the cause is removed. 

 
 

PUSH-BUTTON BLOCKING AND UNBLOCKING 

 

The push-button can be blocked to avoid accidental movements during normal sensor functioning. The 
block can be maintained even after the turning OFF and turning ON of the sensor. The blocking and 
unblocking operations are given below: 
1) With sensor turned OFF press AUTO-SET 
2) Re-power sensor keeping the push-button pressed. The sensor inverts the block status: if the push-

button was unblocked the bock is activated and the red LED is continuously ON, if the push-button 
was blocked the sensor unblocks it and at sensor re-powering the green LED is continuously ON. 

3) The sensor begins to operate with normal functioning. The setting can not be modified if the push-

button is blocked. 

 
 
 
 
 
 
 
 
 

DECLARATION OF CONFORMITY 

We DATASENSOR S.p.A. declare under our sole responsibility that these products are conform to the 2004/108 CEE, 
2006/25/CE Directives and successive amendments. 
 

WARRANTY

 

DATASENSOR S.p.A. warrants its products to be free from defects. 
DATASENSOR S.p.A. will repair or replace, free of charge, any product found to be defective during the warranty 
period of 36 months from the manufacturing date. 
This warranty does not cover damage or liability deriving from the improper application of DATASENSOR products. 
 

DATASENSOR S.p.A. Via Lavino 265 
40050 Monte S. Pietro - Bologna - Italy 
Tel: +39 051 6765611 

Fax: +39 051 6759324 

http://www.datasensor.com     e-mail:  [email protected] 

 

 

DATASENSOR S.p.A. cares for the environment: 100% recycled paper. 
DATASENSOR S.p.A. reserves the right to make modifications and improvements without prior notification. 

 
 

826003050 Rev.A 

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