
9. Appendix
9. 4. Uni-Telway schematic
The
Schematic diagram:
| Master |
|
|
| R | G | 5 V |
|
| ||
|
|
| 4.7 kΩ |
| 4.7 kΩ |
|
|
|
| 0 V |
|
| D(B) |
|
|
120 Ω |
|
| 120 Ω |
1 nF |
|
| 1 nF |
| D(A) |
|
|
| 0VL |
|
|
| 5 V |
| 5 V |
4.7 kΩ | 4.7 kΩ | 4.7 kΩ | 4.7 kΩ |
|
| ||
| 0 V |
| 0 V |
R | G | R | G |
|
|
Slave 1 | Slave n |
Type of trunk cable | Cable with 2 twisted pairs shielded in pairs |
Maximum length of bus | 1000 m at 19200 bps |
|
|
Maximum number of stations (without | 29 stations, i.e., 28 slaves |
repeater) |
|
|
|
Maximum length of tap links | • 20 m |
| • 40 m divided by the number of tap links on a multiple junction box |
Bus polarization | For the master and each slave: |
•One 4.7 kΩ
•One 4.7 kΩ
Line termination | One 120 Ω 0.25 W resistor in series with a 1 nF 10 V capacitor |
|
|
Common polarity | Yes (0 VL) and high impedance placed between 0 VL and the ground in each station |
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