Siemens SIMATIC NET PROFIBUS Instructions d'exploitation télécharger pdf (Page 45)

Installation and Maintenance

5.6 Receive Level of the Optical Channels

SIMATIC NET PROFIBUS Optical Link Module OLM V4.0

Operating Instructions, 01/2013, C79000-G8976-C270-03

5.6 Receive Level of the Optical Channels

Figure 5-11 Position of the level

recording connections

The receive level of the two optical channels CH2 und CH3 can

be measured using a standard voltmeter via the measurement

sockets. The voltmeter can be connected and disconnected

while the device is operating. The OLM is protected against a

short circuit at the measurement sockets; data transmission is

not influenced. The receive level of the two optical channels can

be read in on a PLC using floating high impedance analog

inputs.

This allows

– the incoming optical power to be documented, e.g. for later

measurement (aging, damage)

– a good/bad test to be carried out (limit value).

The measurement must be performed with a high-resistance, ungrounded voltmeter. The ground connector

must not be connected to the housing; otherwise the data traffic could be disturbed. To meet the EMC

requirements, the length of the connected measuring cables must not exceed 3 m. The quality of the bus traffic

can be estimated based on the receiving levels in the following diagram:

Figure 5-12 Relationship between measured output voltage and signal quality

Measured voltage / V

Receiving level at 660 nm / dBm

Receiving level at 860 nm / dBm

Receiving level at 1310 nm / dBm

-4-6-8-10-12-14-16-18-20-22-24-26

-12-14-16-18-20-22-24-26-28

-18-19-20-21-22-23-24-25-26-27-28-29

0,8

0,2

0,4

0,6

1,0

1,4

1,7

2,0

2,5

3,0

3,5

4,0

0,1

Function not guaranteed

Optical system reserve reduced

Normal operation, level sufficient

1 2 ... 40 41 42 43 44 45 46 47 48 49 50 ... 63 64

Commentaires sur ces manuels

Pas de commentaire

Siemens SIMATIC NET PROFIBUS Instructions d'exploitation Page 45

Commentaires sur ces manuels

Produits connexes et manuels pour Mise en réseau Siemens SIMATIC NET PROFIBUS