Aritech ATS4000 Instrukcja Obsługi Pobierz pdf (Strona 35)

ATS Designers Guide 35

• Aritech WCAT54

Use of the abovementioned cables guarantees failure-free operation, and the maximum

declared bus range – 1500m. For data bus wiring, other cables can be used if meet

following requirements: cat 5, twisted pair, STP or FTP.

Table 3-2 Technical parameters of the suggested cables.

Cable type Belden 8723 WCAT52 WCAT54

Description

Cat 5.

Shielded

Twisted Pair

Cat 5.

Shielded

Twisted Pair

Cat 5.

Shielded

Twisted Pair

Wire count 4 4 8

Pair count 2 2 4

Single wire resistance (Ohm/km) 57,4 84 84

Capacity between wires (nF/km) 120 45 45

Capacity between the wire and the

shield (nF/km)

200 100 100

Maximum transmission range(m) 1500 1500 1500

3.1.1.1 Shielding

The data cable shield needs to be connected to the system grounding. Every system

ground needs to lead to a single point, and the shield cannot be grounded on both ends,

due to the risk of current loops in the shield.

D+

+12V

Drawing 3-3 Wire connections in the system bus

When using the ATS1470 isolators, the appropriate grounding rules need to be observed,

and the shield needs to be connected properly. The shield has to be connected only to

one cable, and only on the side of the system from which the isolator draws its power.

3.1.1.2 Power supply

Although such a solution has significant limitations, it is possible to supply peripheral

equipment with power using the data bus. The Drawing 3-3 shows such a connection..

The power supply output efficiency of the data bus is limited to 1A (F4 resistor in the

control panel). Much more restrictive is the transmission cable load limit. The acceptable

voltage for the system components is 10.5V DC. In case of the WCAT52/54 cable a load

of 100mA would cause the voltage to drop from 12V to 10.5V after only 89m of cable. In

case of the Belden 8723 cable such a drop would occur after 131m due to it’s lower

resistance. Detailed calculations can be found in Table 3-3.

To increase the range, the number of power supply wires in the cable can be increased

(in pairs of +12V and 0V), but this solution is not advisable, and under no circumstances

should it exceed a distance of 100m

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