Jetter JM-208-480-OEM, Руководство пользователя

Страница: 110 / 128

14 Counting Input (Option)
110 Jetter AG
14.2.4 Voltage Supply of the Encoder
The optional counter card supplies a voltage of 5 V +/- 5 %.
The EnDat encoders by Heidenhain have been specified to 3.6 through 5.25 V of
0.2 A max. This results in a maximum voltage drop of U = 1.15 V on the EnDat
cable. The voltage drop can generally be calculated as follows:
This results in the maximum cable length or in a minimum cable cross section:
Example:
At a cable cross section of 0.34 mm
2
, there results a maximum cable length of
or - at a cable length of 80 m - the following cross section is needed:
.
By a double wiring arrangement, the cable length can be doubled.
When : Voltage drop in V
: Current consumption by the measuring device in A
: Cross section of the supply cable in mm
2
: Cable length
: Electric conductivity (for copper:
Δ
Δ
U
2 I
n
l
⋅ ⋅
γ
A
⋅
------------------ =
l
Δ
U
γ
A
⋅ ⋅
2 I
n
⋅
------------------------
161
m
mm
2
------------
A ⋅ ⋅
= =
A
2 I
n
⋅
Δ U γ ⋅
---------------
mm
2
161 m ⋅
------------------
l
⋅
= =
Δ
U
I
n
A
l
γ
56
m
Ω mm
2
-----------------


l 54.74 m
=
A 0.5 mm
2
=