Lenze SMVector RS-485 LECOM - Manual (Page 8)

6 CMVLC401A
Installation
3.2 RS-485 Terminal Block
For a LECOM network, wire the RS-485 connector as detailed in Table 3.
Table 3: RS-485 Pin Designation
Terminal Description Important RS-485 Connector
1 Earth ground / shield For reliable communication make sure terminal is
connected to the LECOM network GND/common. If
only two wires are used (TXA and TXB) in the network,
connect Terminal 1 to chassis/earth ground.
1 2
3 4
5
2 TXA If controller is located at either end of the network,
a terminating resistor (120ohm typical) should be
connected across TXA and TXB
3 No connection
4 TXB
5 No connection
Protection against contact
• All terminals have basic isolation (single insulating distance)
• Protection against contact can only be ensured by additional measures (i.e. double insulation)
3.3 Electrical Installation
3.3.1 Cable Types
For RS-485 LECOM-B networks, use a quality shielded twisted pair cable. The use of low quality cable will result in
excess signal attenuation and data loss.
3.3.2 Network Limitations
There are several limiting factors that must be taken into consideration when building an RS-485 LECOM network:
• LECOM-B networks are limited to: 31 devices (w/o repeaters); 90 w/ repeaters).
• Topology: Without repeaters: line; with repeaters: line or tree.
• Maximum total network length is 1200 m depending on the baud rate and cable used.
• Minimum of 1 meter of cable between nodes.
3.3.3 Connections and Shielding
To ensure good system noise immunity all networks cables should be correctly grounded:
• Minimum grounding recommendation: ground the network cable once in every cubical.
• Ideal grounding recommendation: ground the network cable on or as near to each drive as possible.
• For wiring of cable to the connector plug the unscreened cable cores should be kept as short as possible;
recommended maximum of 20mm. The shield connection of terminal 1 should also be wired to earth (PE).
20mm
max
Connect to
drive earth
(PE)
1 2 3 4 5
Figure 4: Connector Wiring Diagram