Siemens SIMATIC NET PROFIBUS Provozní pokyny stáhnout pdf (Strana 36)

Installation and Maintenance

5.1 Installation

SIMATIC NET PROFIBUS Optical Link Module OLM V4.0

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

Please note the following:

A minimum distance of 15 cm must be maintained between an OLM and a load switching

element (e.g. contactor, relay, temperature control, switch, etc.). This minimum clearance is

measured between the outside edges of the components and must be adhered to in all

directions around an OLM. The power supply lines (24 V DC) of the OLM must not be laid in

the same cable duct as power lines (load circuits).

The lines +24 V DC and GND should be twisted with each other.

 Recommendations on the arrangement of devices and lines with the aim of achieving the

lowest mutual influence possible can be found in EN 50174-2.

 For applications in environments with heavy electromagnetic interference and for use in

shipbuilding, the retry value in the PROFIBUS master must be set to 4.

 Bus cable shields.

Note the following measures for shielding lines:

- Use completely shielded SIMATIC NET PROFIBUS cables. The shields of these cables

have a density high enough to meet the legal requirements for disturbance emission and

immunity.

- Always connect the shields of bus cables at both ends. The legal requirements for

emissions and immunity can only be met by connecting the shield of the bus cables at both

ends (CE mark).

- Secure the shield of the bus cable to the connector housing or the cable clamps.

- In stationary use, it is advisable to strip the insulation of the shielded cable over the entire

length damaging it and to lay it on shielding/grounding rail.

Note:

If there are potential differences between the grounding points, an unduly high compensating

current may flow over the shield connected at both ends. Under no circumstances

disconnect the shield of the bus cable to solve the problem.

The following solution is permissible.

Install an extra equipotential bonding cable parallel to the bus cable and this can then take

up the shield current.

1 2 ... 31 32 33 34 35 36 37 38 39 40 41 ... 63 64

Žádné komentáře

Siemens SIMATIC NET PROFIBUS Provozní pokyny Strana 36