Operating Instructions
Non-Contact Safety Switch CES-AR-C.2-…
12
(Translation of the original operating instructions) 2109309-09-03/20
8.5.1. Determining cable lengths using the example table
Example: 6 switches are to be used in series. Cabling with a length of 40 m is routed from a safety relay in the control
cabinet to the last switch (#6). Cables with a length of 20 m each are connected between the individual safety switches.
CES-AR # 6
Sicherheits-
relais
Safety Relay
CES-AR # 5
CES-AR # 4
CES-AR # 3
CES-AR # 2
CES-AR # 1
STAT
E
DIA
STAT
E
DIA
STAT
E
DIA
STAT
E
DIA
STAT
E
DIA
STAT
E
DIA
l
1
= 40 m
l
2
= 5 x 20 m
l
max
= 140 m
l
n
= 20 m
u
n
= min. 19,2 V
i
out
= min. 75 mA
Figure 1:
Circuit example with six CES-AR
A safety relay is connected downstream that consumes 75 mA at each of the two safety inputs. It operates over the whole
temperature range with a voltage of 19.2 V (corresponds to 24 V - 20%).
All the relevant values can now be determined using the example table:
1. Select the corresponding section in the column n (max. number of switches). In this case: 6 switches.
2. In column I
OUT
(possible output current per channel OA/OB), find a current greater than or equal to 75 mA. In this case:
100 mA.
¨
It is then possible to determine the maximum cable length from the last switch (#6) to the control system from column
l
1
. In this case, a length of 50 m is permitted.
Result: The desired cable length l
1
of 40 m is below the permitted value from the table. The overall length of the switch
chain l
max
of 140 m is less than the maximum value of 200 m.
¨
The planned application is therefore functional in this form.
