Pepperl+Fuchs LS611 Series User manual

MANUAL
FACTORY AUTOMATION
Optical data coupler
LS611-DA-P
LS611-DA-P/35

Date of issue 07/02/2007 Part No. 194341
With regard to the supply of products, the current issue of the following document is applicable:
The General Terms of Delivery for Products and Services of the Electrical Industry, published by the Central
Association of the Electrical Industry (Zentralverband Elektrotechnik und Elektroindustrie (ZVEI) e.V.)
in its most recent version as well as the supplementary clause: "Expanded reservation of proprietorship"

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Date of Issue 07/02/2007 Part No. 194341
Optical data coupler LS611
Table of Contents and General Information
1 Quick Reference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.1 Tools required. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.2 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.3 Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.4 Bus connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
1.5 Setting the baud rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Validity of this instruction manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3 Scope of delivery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4 Principle of operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.1 PROFIBUS data transmission . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Safety instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6 Initial operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.1 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
6.2 Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.2.1 Alignment aid / stability control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6.2.2 Using the adjustment device for alignment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6.3 Parallel optical paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.4 Parallel arrangement of distance measurement devices EDM/VDM . . . . . . . 13
6.5 Electrical installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.5.1 Power supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6.5.2 Installation guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.5.3 Customisation of the bus plug connector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.5.4 Grounding / screening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.5.5 Bus termination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.6 Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7 Function displays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
7.1 Adjustment of the bus parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.1.1 Adjustment of the baud rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.1.2 Switching C1CP on or off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7.2 Notes on the adjustment of the PROFIBUS operating parameters . . . . . . . . 20
8 Special instructions when using several masters . . . . . . . . . . . . . . 20
8.1 Problem after light beam interruption in multi-master systems . . . . . . . . . . 21
8.2 Preventing collision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
8.3 Using C1CP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
9 Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
10 Fault finding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
10.1 General problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Date of Issue 07/02/2007 Part No. 194341
Optical data coupler LS611
Table of Contents and General Information
4
10.2 PROFIBUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
11 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
12 Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
13 Accessories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
14 Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
General information
This symbol warns the user against a potential device failure.The non-
observation of these warning notes may lead to the complete failure of
the device or any other device connected.
This symbol draws the user's attention to the important instructions.

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Date of Issue 07/02/2007 Part No. 194341
Optical data coupler LS611
Table of Contents and General Information
Declaration of conformity
We, Pepperl+Fuchs GmbH, herewith declare our sole responsibility for the fact that the
Optical Data Coupler LS611
and all models of this product, which are included in this declaration, are in conformity
with the following standards and other controlling documents
DIN EN 61326-6-2, issue:1998-01, 1998-05
Product family standard: Electromagnetic compatibility (EMC for control systems,
industry)
Pepperl+Fuchs GmbH of D-68301 Mannheim operates a certified quality assurance
system in accordance with ISO 9001.
A corresponding declaration of conformity can be requested from the
manufacturer.
ISO9001

Date of Issue 07/02/2007 Part No. 194341
Optical data coupler LS611
Table of Contents and General Information
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Date of Issue 04/22/2008 Part No. 194341
Optical data coupler LS611
Quick Reference
1 Quick Reference
1.1 Tools required
• 7 mm key to fit the M4 nuts of the adjustment device.
• Allen key, size 5 for M6 screws (central attachment, X and Y adjustment)
1.2 Mounting
Attach the wall angle and place the adjustment device in the requested direction.
Tighten the M4 nuts. Do not tighten the M6 screw.
1.3 Adjustment
Make both devices alive. Bus operation is not required!
Using X and Y adjustment for a moderate distance (< 20 m):
• Find contact
--> Fast flashing of the opposite sides stops and switches to slow flashing
• Find maximum
--> Sets the bar graph display of the opposite side to maximum
Check the adjustment at maximum distance, and correct, if and when required.
The adjusted position is secured by tightening the central M6 screw.
For detailed instructions on adjustment, please refer to chapter 6.2.
1.4 Bus connections
We recommend the attachment of the screen to the screw connection of the M12 con-
nector. If this is ensured, Pin5 need not be connected. The pin assignment is printed on
the device. The M12 socket "Bus OUT/Termination" can be used to terminate the bus ca-
ble by means of a PROFIBUS terminator (cf. chapter 13 Accessories).
1.5 Setting the baud rate
Press the button for longer than a second in order to enter the baud rate adjustment
mode. If the LED of the selected baud rate is flashing, it can be changed by pressing
shortly.
(for detailed instructions, please refer to chapter 7.1 Adjusting the bus parameters).
With the locking lever pressed together, place the LS611 and release the lever.
This action can also be carried out when the cables have already been attached.

Date of Issue 04/22/2008 Part No. 194341
Optical data coupler LS611
Validity of this instruction manual
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2 Validity of this instruction manual
Pepperl+Fuchs VISOLUX supplies the LS611 for two different detection ranges.
Table 2.1 Device types
Two identical LS611 devices are required for a data transmission path.
3 Scope of delivery
Check the delivery for completeness after opening the packaging.
• Optical Data Coupler LS611
• Instruction manual
• Grounding set (grounding clip and nut)
4 Principles of operation
The LS611 is a device used for serial data transmission of the PROFIBUS. The data
transmission speed varies between 93.75 kbit/s and 1.5 MBit/s.
The data are transmitted in both directions by means of modulated infrared light.
4.1 PROFIBUS data transmission
All types of PROFIBUS protocols are supported:
• PROFIBUS DP: DP-V0, DP-V1 and DP-V2 (Decentral periphery)
• PROFIBUS FMS (Fieldbus Message Specification)
• Mixed operation FMS-DP
• MPI (Multi Point Interface)
• Profisafe
In order to prevent a disturbance of the connected bus operation in case of a potential
interruption of the light beam, the "Telegram Verification Technology" (TVT) has been im-
plemented. TVT prevents the transmission of invalid telegrams. The signals are regen-
erated according to bits and characters and are sent to the bus by a crystal-controlled
process. This method ensures perfect signal conditioning. The signal quality is electrical-
ly and temporally identical with the original PROFIBUS station.
A switch-on "C1CP" function is used to prevent a collision with the master of the control
system in case of "multi-master operation".
For more information, please refer to chapter 8 "Special instructions when using several
masters".
Designation Operating range
[m]
LS611-DA-P 150
LS611-DA-P/35 300

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Date of Issue 04/22/2008 Part No. 194341
Optical data coupler LS611
Safety Instructions
5 Safety Instructions
The LS611 is LED operates and corresponds to the laser protection class 1 in accor-
dance with EN 60825.
If the LS611 is used as intended, the device is not cause any hazards for apparatuses
and operating staff.
6 Initial operation
6.1 Mounting
If existing adjustment and mounting facilities are to be used, M4 inserts can be pressed
into the housing foot fixtures; to be ordered as an accessory (page 27) Pos. 7.
The accessory OMH/LS610-01, a mounting aid for attachment to walls, permits a fast in-
stallation and adjustment.
Illustration 6.1 Mounting aid OMH-LS610-01 for wall attachment
The mounting aid (OMH-LS610-01) consists of a holding angle and a pre-mounted ad-
justment device (X and Y direction). The mounting aid can be used to set the requested
direction of beam (±90° rotation); the two M4 screws and the central M6 screws can be
used for the attachment to the holding angle. The central screw is used for attachment
after the adjustment, which should be tightened only after the adjustment has been com-
pleted.
Do not look into the beam from a short distance! The operating voltage has to be
provided by power supply units with safe electric isolation in accordance with EN
60742 (IEC60742). Interventions in the device are not intended and not permissi-
ble. Damaged devices shall have to be removed immediately. The connection of
the devices as well as any servicing work on them, in particular in live condition,
may be carried out by qualified experts only.
ø8.5
80
4426
200
100
100
266

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Optical data coupler LS611
Initial operation
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The optical data coupler's feed are placed into the recesses of the adjustment device by
pressing the two bars on the front together. The feet have to lock into place in such a way
that the bars can be pressed to the outside up to the stop; if necessary the optical data
coupler has to be pressed down applying some force from the top to the center. (cf. illus-
tration 6.2)
Illustration 6.2 Mounting the optical data coupler LS611 with the adjusting device
6.2 Adjustment
6.2.1 Alignment aid / stability control
A clearly visible alignment LED (alignment aid) has been fitted to the adjustment device.
As soon as a receiver recognizes the emitter's light of the opposite device, the flashing
frequency of the alignment aid is reduced. By going off in the end, the alignment LED in-
dicates that the devices are optimally aligned, and that sufficient stability has been en-
sured. For fine adjustment, the optical data coupler has been provided with an additional
bar graph display which permits optimal alignment.
Illustration 6.3 Alignment aid
Alignment aid

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Optical data coupler LS611
Initial operation
Illustration 6.4 Relationship between display and operating condition
If "Stability" (green section) is displayed, the optical data coupler is operating at a receiv-
ing strength sufficient to ensure operation. Within the effective operating distance, the
LS611 has to operate in the green section (at least one green LED). If the receiving
strength falls below this threshold value, the alarm output is switched off. If the received
strength falls below the limiting value required for operation (no yellow LED), messages
are no longer safely transferred. An unsafe transfer in the red range is also possible.
A very fast evaluation of the signal level is carried out internally for each individual mes-
sage and does not run precisely in synchronization with the bar graph display.
6.2.2 Using the adjustment device for alignment
By means of the alignment aid of the opposite optical data coupler and the two adjust-
ment screws (5 mm Allen key) of the adjustment device, the beam axle is aligned in X
and Y direction.
The transmitting angle is smaller than the receiving angle, which means that the
bar graph as well as the alignment LED is decisive only for the alignment of the
opposite side. It is only if the two optical data couplers have been set to the same
baud rate, that the bar graph renders the correct signal strength.
State weak signal sufficient signal strength signal with function reserve
Transmission lock-up may occur released transmission with
function reserve
Alignment-LED fast flashing slowflashing off
Signal-indicator red section yellowarea green section
(at least one LED)

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Optical data coupler LS611
Initial operation
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Illustration 6.5 Adjustment of the optical data coupler
Bus operation is not required for alignment.
• Screw the central M6 screw into the lower side of the adjustment device, but do not
tighten yet. (Tightening prevents horizontal movement).
• Roughly align the optical data coupler at a distance of approx. 3 m to 5 m until both
signal displays are in green section. In the process, please make sure that the optical
data couplers are equally high and not displaced.
• At approx. 20 m, turn the adjustment screw for the Y direction until the alignment LED
(cf. illustration 6.3) on the opposite side starts flashing slowly. Subsequently turn into
the opposite direction, and count the revolutions in the process (during which the align-
ment LED remains off) until the alignment LED starts flashing again. Then turn the ad-
justment screw back by half a turn (the center). Carry out the same procedure for the
X direction.
• Increase the distance to the maximum distance; readjust, if and when necessary.
• Tighten the central M6 screw in order to secure the adjustment in horizontal direction.
6.3 Parallel optical paths
If several optical paths are fitted next to each other without optical separation, the spac-
ing between the optical axes has to be observed to reduce crosstalk.
The arrangement in keeping with illustration 6.6 has to have an axis spacing of half the
maximum size of the emitter spot, which for this reason depends on the distance.

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Date of Issue 04/22/2008 Part No. 194341
Optical data coupler LS611
Initial operation
For the arrangement rendered in illustration 6.6 the minimum distance a has to be deter-
mined as follows:
a = 1 m + d · 0.018 All units in meter [m]
e.g. d = 100 m --> a = 2.8 m
Illustration 6.6 Parallel arrangement
This calculation applies in case of ideal alignment of the device, i.e. the bar graph display
of the optical data couplers are extended as far as possible (in case of maximum travel).
In such an arrangement, a one-sided shutdown of an optical data coupler is not permis-
sible. Moreover, the light beam must not be interrupted either.
6.4 Parallel arrangement of distance measurement devices EDM/VDM100
For the frequently found combination of optical data coupler and range finder of EDM /
VDM100 type, it has to be made sure that the laser beam of the EDM / VDM100 does not
illuminate the optical data coupler lens during operation. Potential failures are caused by
the reflection of the reflector in case of medium distance (10 m to 50 m).
The EDM / VDM100 is not disturbed by the optical beam of the optical data coupler.
The alignment of the optical data coupler on the EDM / VDM100 side may be significantly
disturbed by the reflector. For this reason, the optical data coupler has to be covered dur-
ing the adjustment process.
The spacing between the optical axes should not be any smaller than 1 m.
When the optical data coupler on the reflector side is switched off, bus failure may be
caused by the live optical data coupler.
LS611 LS611
LS611 LS611
a
d

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Optical data coupler LS611
Initial operation
14
Illustration 6.7 Parallel operation of EDM / VDM100 range finders and optical data coupler LS611
6.5 Electrical installation
In order to ensure IP65 type of protection, the unused M12 connectors have to be pro-
vided with protective caps. The protective caps can be ordered as accessories. (cf. chap-
ter 13)
Illustration 6.8 Electrical connection
EDM
DLS
F2
DLS
F1
Light spot of EDM-emitter
Reflector
spacing between
the optical axes
34
21
34
21
5
1
4
2
3
5
Alarm
Power
Keylock
Shield
1)
Shield Shield
Shield
1)
BUS OUT/TerminationBUS IN
Socket M12 x 1, 5-pin
B-coded
Plug M12 x 1, 4-pin
A-coded
Plug M12 x 1, 5-pin
B-coded
4
1
2
3
24 V DC
0 V DV
4
1
2
3
5
VP
DGND
4
1
2
3
5
n.c.
n.c.
Rx/Tx-N (A)
Rx/Tx-P (B)
Rx/Tx-N (A)
Rx/Tx-P (B)
n.c.

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Optical data coupler LS611
Initial operation
6.5.1 Power supply
The device is in conformity with protection class III. Please observe that the power supply
has to be ensured by power packs, which supply protective low voltage (PELV). The
grounding of the cable screens on the metal plug-in connectors is not protective ground-
ing in the sense of personal protection, but rather a protection of function. The power sup-
ply of the LS611 is 18 V DC to 30 V DC.
6.5.2 Installation guidelines
We recommend to observe the guidelines rendered in the "Handbook PROFIBUS Instal-
lation Guideline". It can be downloaded at www.PROFIBUS.com.
6.5.3 Customization of the bus plug connector
In case of non-customised plug-in connections, the screen plug-in connectors, such as
the V15B-G (chapter 13) accessory parts, should be used.
In the process, please observe the following working steps:
Illustration 6.9 Bus connector assembly
1. First, push all housing parts with the exception of the insert and the coupling socket
on to the bus cable.Please observe the sequence: pressure screw; clamping block;
seal; shield ring.
2. Stripping the cable and peeling off the cores: (illustration 6.10)
Illustration 6.10 Cut the cable to length
female insert
sleeve
seal
pinch ring
pressing screw
shielding ring
shield
without foil
approx.
4 mm
approx.
5 mm
approx. 40 mm

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Optical data coupler LS611
Initial operation
16
3. After fitting the coupling socket, use a screwdriver to close the two screw terminals.
Please observe the torque when tightening.
Illustration 6.11 Assembly of connector and cable
Do not contact the middle Pin5 (if present).
4. Screw the socket to the respective insert (socket/connector).
Illustration 6.12 Mounting socket/connector and cable
5. Flush mount the shield ring to the sheath end, and lay the braiding over the narrow
part of the shield ring. Now push the shield ring together with the cable and seal into
the socket until the sealing ring of the shield ring touches the socket. If wires of the
shield prevent the unit being pushed in, they have to be shortened correspondingly.
6. Close up the plug-in connector by screwing the pressure screw to the socket.
Pin Connection Old standard designation
2 A, green RxD / TxD-N
4 B, red RxD / TxD-N
5 Connection not recom-
mended.
Screen/housing Screen
2 4
2 4
green red

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Optical data coupler LS611
Initial operation
6.5.4 Grounding / shielding
In order to retain the interference immunity, functional grounding of the cable shields is
required.
For shield grounding, the plug-in stud (contained in the scope of supply) has to be
screwed to one of the bus connectors used. Use the nut also enclosed for attachment.
By no means open the primary attachment nut of the plug-in connector. The connecting
assembly may be damaged and the housing may become leaky. The plug-in stud should
be contacted to a low-impedance connection of the surrounding metal parts (such as
mounting socket, frame).
Illustration 6.13 Optical data coupler with grounding set mounted
6.5.5 Bus terminal
If the optical data coupler is located at the end of a bus line, the bus termination is pro-
vided by the connection to an external standardized terminal (cf. chapter 13) of the
M12 socket "Bus OUT /Termination“.
As the case may be, all bus lines have to be terminated. (cf. illustration 6.16).
Illustration 6.14 Internal switch circuit of the terminal
This type of grounding is no protective grounding. It is used only to dis-
charge cable faults, and does not have to meet any safety guidelines
(e.g. personal protection) whatsoever.
DGND (3)
Rx/Tx-P (4)
VP (1)
Rx/Tx-N (2) A
B
390 Ohm
220 Ohm
390 Ohm

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Optical data coupler LS611
Initial operation
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As the internal bus connections are switched parallel, the inputs and outputs for the bus
cable are identical for the bus cable.
6.6 Topology
A pair of optical data couplers acts as a repeater; the maximum bus cable lengths refer
to the respective segments only. In case of illustration 6.16 the maximum length can be
laid between the terminating resistors, and the maximum number of stations can be con-
nected to all lines.
Table 6.15 Topology
Like in repeaters, star or tree topologies may be set up through light paths.
Illustration 6.16 Topology
Baud rate
[kBit/s]
Maximum segment length
[m]
93.75 1200
187.5 1200
500 400
1500 200
A
A
A
A
A A
A
AA A
LS611 LS611 LS611
LS611 LS611 LS611
LS611 LS611
A
Units Units
Units Units
Units Units Units Units
= Terminal resistor

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Optical data coupler LS611
Function displays
7 Function displays
When the bus is active, a yellow LED "RX" lights up to indicate data reception from the
light path, and a green LED "TX" is lit to indicate data transmission to the light path.
Illustration 7.1 Function displays
7.1 Adjustment of the bus parameters
Illustration 7.2 Control panel
In order to prevent any manipulation or inadvertent changes of the parameters, the key
can be blocked by means of an electric signal. An attempt to change the parameters in
this condition will be acknowledged by simultaneous flashing of all mode LEDs. The lock
is activated by applying a high voltage level to the "KEY LOCK" pin.
The push-button key can be used to set the baud rate or to switch on or off the C1CP
function (cf. chapter 7.1.2).
7.1.1 Setting the baud rate
Press the button for longer than a second in order to enter the baud rate adjustment
mode. The LED of the position to be changed flashes. By pressing the key shortly, the
position can be moved forward. When the requested baud rate starts flashing, a short
wait will cause the return to the normal operating mode. The requested baud rate is dis-
played permanently, and is thus set. The setting process is thus completed.
If a PROFIBUS master (active station) is located on the opposite side, the wrong baud
rate setting will be indicated as an error by the error LED. If the baud rate of the opposite
side is wrong, and a master is located exclusively on the side of the indicator viewed, no
error will be displayed as all telegrams are already suppressed by the bus of the opposite
side.
7.1.2 Switching C1CP on or off
Press the button for longer than a second in order to enter the baud rate adjustment
mode. The C1CP function can be switched on or off here. The LED of the position to be
changed flashes. By brief actuation of the key, the position can be moved forward until
the "C1CP" LED starts flashing. After a short wait without key actuation, the normal op-
erating mode will be activated again. The "C1CP" function has now been activated or de-
activated, and will be displayed permanently. The setting process is thus completed.

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Optical data coupler LS611
Special notes on the use of several masters
20
7.2 Notes on the adjustment of the PROFIBUS operating parameters
Optical data couplers are to be considered a cable extensions.
For this reason, no changes have to be made to the PROFIBUS parameters, if all stations
connected to the bus correspond to the PROFIBUS DP standard.
PROFIBUS FMS devices are not subject to the performance characteristics (such as re-
sponse time) of the PROFIBUS DP standard.
The time parameters here may be observed as follows:
An optical data coupler LS611 delays the signal by 15 bit times and 1 µs (table 7.3, “Time
parameter of the optical data coupler LS611,” on page 20).
In case of PROFIBUS stations which are known to be slow (such as software based test
computers), the slot time "TSLOT" should be increase by the value of the delta slot.
Table 7.3 Time parameter of the optical data coupler LS611
8 Special notes on the use of several masters
When using the PROFIBUS protocol, the time sequence of the bus traffic is determined
by the "active" bus station or by a master. In general, the PROFIBUS DP has been de-
signed as a mono master system, which means that there is only one master in the bus
segment, which as a rule is used as an interface to the control system (or PLC). This
master is referred to as Class1-Master. All other stations are passive, and are referred to
as slaves.
In some applications, however, several active stations are used, which frequently may
be the case in operating elements ("touch panels"), for example. However, due to their
communication relationship to the PLC these devices also have to have the properties of
an active station. As no fast (cyclical) connections are operated with slaves, and the
Class1-Master only is used for communication as a rule, it is not always realized that
such a station also has the functional range of a master. In this case, a so-called "Class2-
Master" (acyclical connection) is used.
The existence of the Class2-Master within a certain topology is significant for the analysis
of sequence errors after the interruption of the light beam.
If two optical data couplers wired after each other (for the additional transmission in Y
direction, for example), (cf. illustration 8.1), and if the Class2-Master is located behind the
During the setting mode, no changes are carried out. The device contin-
ues to operate with the previous baud rate without interruption. As the
C1CP function has an effect only when the light beam is interrupted,
switching on or off has not influence on the normal operation.
Baud rate Absolute delay DeltaSlot
[kBit/s] [bit] [µs] [bit]
1,500 17 11.1 34
500 16 31 32
187.5 15 80.8 31
93.75 15 161 31