5
F3EM
Measuring lightcurtain in robust aluminium housing
Analog Output Models (F3EM-_-AV)
DIP Switch Settings
If F3EM is operated in a distance < 1m, the sensitivity can be
set to NEAR operation. This could be necessary, if multiple
light curtains are installed close to each other, or if the light
curtain detects semi-transparent objects.
The analog output can operate either in STANDARD mode or
INVERTED mode:
• STANDARD mode: 0 V (if no beams is interrupted) to 10 V
(if all beams are interrupted)
• INVERTED mode: 10 V (if no beams is interrupted) to 0 V
(if all beams are interrupted)
Please find the DIP switch setting below:
Analog output value
The output value is related linear to the number of beams in-
terrupted by the object to be measured. For STANDARD
mode:
Output voltage = (10/ n° of optical units) * n° of interrupted
beams [VDC]
If multiple objects are inside the sensing area, the system will
read the total number of beams interrupted accordingly. Re-
ferring to the illustration below, the F3EM provides an output
signal in proportion with the sum of A+B:
Serial Output Models - RS232 (F3EM-_-D2)
The RS232 serial interface of F3EM is specified as follows:
• Full duplex operation
• Data format: 8-N-1 (bit start - 8-bit data - 1-bit stop - no
parity)
Transmission speed setting (Baud Rate)
The baud rate can be set by DIP switch 1 and 2.
@
The baud rate must be set both on the receiver bar
dip-switches as well as the transmitter bar dip-switch-
es to align the timing synchronism of the two bars.
Communication protocol
The communication of serial interface provides two possible
operation modes:
• Command-response
• Triggered by external input
A) In command-response mode the command is 1 byte:
Command (hexadecimal) = 'BF'
The light curtain responds with a fixed number of bytes de-
pending on the number of light beams.
E.g. the response of a light curtain with 20 beams is 3 bytes:
The response bytes are composed by each bit representing
the status of each beam in the order as in the example above.
Remaining unused bits in the last byte are set to zero.
Each bit signals:
0 = BEAM NOT INTERUPTED
1 = BEAM INTERRUPTED
This drawing shows how the beams
are numbered on the light curtain
As a result each response byte contains 8 beams. The follow-
ing formula applies for the calculation if the number of re-
sponse bytes:
number of bytes = INT (number of optical units + 7) / 8)
The maximum number of optical beams that can be managed
is 400.
B) Trigger by external input
Alternatively the response can be forced by signal on the
STROBE input (PNP logic); the light curtain responds on the
serial line with the same protocol explained above.
Measurement method
In order to avoid missing information the light curtain stores in-
terruption of beam signals until the status is sent in the next
protocol response. After the response is sent the interruption
status is reset (all bits to zero).
The beams are scanned sequentially. Therefore it can occur
that a command or trigger arrives before the scan is complet-
ed. In this case the scan is interrupted and the status of the
scan before is transferred in the response protocol.
Switch
1
2
3
4
not used
not used
Distance setting (NEAR
position recommended if
distance is <1 m
Operation mode
ON
NEAR
ON
DECREASING
OFF
FAR (default)
OFF
INCREASING
(default)
DIP Switch 1
DIP Switch 2
Baud Rate (bps)
OFF
OFF
4800
OFF (default)
ON (default)
9600 (default)
ON
OFF
19200
ON
ON
38400
B
A
1
st
byte
8
7
6
5
4
3
2
1
2
nd
byte
16
15
14
13
12
11
10
9
3
rd
byte
0
0
0
0
20
19
18
17
