Bus Physics & Wiring

9 Copper

9 Fiber optic

9 Infrared & RF components

Network consists of RS485 segments

Proper installation

required

Connected via repeaters New segment when

maximum length or number of devices per

segment is reached

Segment 2 Segment 1

Isolation

Segment 1

100 100 200 100

1,000 400 1,000

1,000 1,000

4,000

2,000 10,000

1,000 1,000

1,000 10,000

10,000 10,000

0 2,000 4,000 6,000 8,000 10,000 12,000

9.6 19.2 93.75 187.5 500 1,500 3,000 6,000 12,000 [kbaud]

Network [m]

Segment [m]

up to 9 in a r ow up to 9

in a r ow

9 Up to 126 addressable nodes per network 9 Up to 32 devices per segment

Repeater PROFIBUS

Nodes (e.g. I/O)

Optical Link Modules

(OLMs)

! No PRO FIBU S Ad dre ss !

! No PRO FIBU S Ad dre ss !

‰ What counts as “device”?

Address #0 Address #30 Address #31 Address #60

Address #90 Address #61 Address #120 Address #91

Address #121 Address #125

= Repeater

= OLM No Address

No Address

No Address No Address

addressable nodes per

network Up to 32 devices per

segment

Shielding &

Grounding

Drop Lines

Termination Cable

Distances

9 Improves EMC behavior

9 Provides a low impedance (short) return path for noise and current

9 Reduces the emission from the bus

Shield is not always connected to !!!

protective GND within the devices;

therefore, make sure the cable shield will be connected to GND before it

enters or leaves the cabinet

!!!

Shield is not always connected to !!!

protective GND within the devices;

therefore, make sure the cable shield will be connected to GND before it

enters or leaves the cabinet

!!!

Cable Category

II

>= 20 cm

>= 10 cm >= 10 cm

>= 50 cm

>= 50 cm

>= 50 cm Cable

Category I

Cable Category

III

Cable Category

IV

9 Category I:

• LAN cables (e.g. Ethernet)

• Other communication cables

9 Category II:

• Shielded and unshielded cables for DC voltages > 60V and <= 400 V

• Shielded and unshielded cables for AC voltages > 25V and <= 400 V

9 Category III:

• Shielded and unshielded cables for DC and AC voltages > 400 V

9 Category IV:

• Signal cables of categories I - III at risk from direct lightning strikes,

e.g., connections between components in different buildings

9 Every branch or drop directly from the cable

9 Stubs to devices cause reflections (additional capacitance) 9 Repeaters are not spur-lines

RS485

(A) (B)

Internal to device

Between device and trunk line

Device

RS485

Device

! M anu fac ture r !

! M anu fac ture r !

100

0 0 6.6 0

33 20

500 500

0 50 100 150 200 250 300 350 400 450 500 550 600

9.6 19.2 93.75 187.5 500 1,500 3,000 6,000 12,000

[kbaud]

Allowed Length [m]

Fo r D ro ps ab ov e 18 7.5 kBa ud : us e Bu

s T er mi na ls or Re pe ate rs Fo r D ro ps ab ov e

18 7.5 kBa ud : us e Bu

s T er mi na ls or Re pe ate rs

Although stub lines can theoretically be tolerated at the

lower baud rates, the recommendation is to avoid the use

Although stub lines can theoretically be tolerated at the

lower baud rates, the recommendation is to avoid the use

9 Termination for each segment at BOTH ends

9 Termination works ONLY when supplied with power

Vi a

Co Vi nn a ec to r

Co nn ec to r Vi a Ac tiv e

Te rm ina tio n B ox Vi a Ac

tiv e

Te rm ina tio n B ox

Vi a i nt eg ra ted DI P Sw itc he s Vi a i nt eg ra ted

DI P Sw itc he s

OLM OLM OLM

Repeater

4x

3. Insert the end of the cable into the stripper using your left index finger as a limit stop to ensure the correct length is inserted.

1. How to hold the insulation stripper in your right hand.

2. Match up the cable end with the template so that your left index finger is against the end surface of the tool.

6. With the clamp still closed,

4. Clamp the cable firmly in 5. Rotate the stripper around

9. After removing the insulation from the cores, the cable can be fitted into the PB connector.

7. The removed insulation remains in the stripper. After releasing the clamp, the remnants can be removed.

8. Pull the protective foil off the cores.

* green wire A

* red wire B

9 Plastic, PCF and glass fiber optic available

8 Plastic - 50m between 2 Optical Link Modules (OLM) 8 PCF - 300m between 2 OLMs

8 Glass - up to 15km between 2 OLMs

9 Connections via modules or integrated interface

‰ When is Fiber Optic the Choice?

; Noise immunity & independence from potential differences

; Cover longer distances

; Line, ring and star configuration possible

;

OLM

PROFIBUS FO -

Glass, PCF or Plastic

= Optical Bus Terminal (OBT)

PROFIBUS FO -

PCF or Plastic

; Wireless linking of devices (up to 15m)

; Communication with moving devices

; Communication with changing devices

; Noise immune

; Ground independent

‰ More Options... RF Technology

; http://www.micro-control.no

; http://www.akerstroms.no