Siemens M7-400 Benutzerhandbuch

5-59

S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07

You can use the analog output modules to supply loads and actuators with current
and voltage.

This section contains general information that is generally applicable to all the
connection options for loads and actuators described in the sections that follow.

For

 

the

 

analog signals

, 

you should

 

use

 

shielded

 

and

 

twisted

 

pair

 

 

cables. The cables

Q

V

 and S+ and M and S–, respectively, are to be twisted together.

 

This

 

reduces

 

the

interference

.  

Ground

 

the screen

 

of the analog cables at both ends of the cables.

If there are potential differences 

 

between 

 

the cable 

 

ends, an equipotential 

bonding 

 

current, which 

 

can flow 

 

over the 

 

shield, can 

 

cause interference of the

analog signals. In such a case, you should ground the shield at one end of the
cable only.

With the isolated analog output modules there is no electrical connection between
the reference point of the measuring circuit M

ANA

 and chassis ground.

You must use isolated analog output modules if a potential difference U

ISO

 can

occur between the reference point of the measuring circuit M

ANA

 and chassis

ground. By means of an equipotential bonding conductor between the M

ANA

terminal and chassis ground, make sure that U

ISO

 does not exceed the permitted

value.