EUCHNER CTP - Determining Cable Lengths Using the Example Table

Operating Instructions
Transponder-Coded Safety Switch CTP/CTA-L1/2-BR
22
(translation of the original operating instructions) 2537376-01-04/21
10.5.1. 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.
CTP/CTA-BR-...-SAB # 6
Sicherheits-
relais
Safety Relay
CES-I-BR # 5CES-I-BR # 3
CES-I-BR # 2
CES-I-BR #
1
CTP/CTA-BR-...-SAB # 4
l
1
= 40 ml
2
= 5 x 20 m
l
= 140 m
l
n
= 20 m
u
n
= min. 19,2 V
I
FO1A/FO1B
= 75 mA
Figure 3: Circuit example with six CES-C07/CTP/CTA-BR-…-SAB
A safety relay is connected downstream that consumes 75mA at each of the two safety inputs. This 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 the column I
FO1A/FO1B
(possible output current per channel FO1A/FO1B), nd 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.