Lenze smd Series Drives - Manual (Page 7)

3 RG-SDMOD
Introduction
2 Introduction
This document defines the specifics required for Modbus serial communication with a Lenze-AC Tech
standard
smd Series drive for control, status monitoring, and programming parameters. A familiarity
with normal drive capabilities and operations is assumed. If this is not the case, refer to the smd Series
Operating Instructions (SL03) for more information.
2.1 RS485 Details
Only standard smd models with an “L” as the eighth digit in the model number (ex. ESMD371L4TXA) are
equipped with Modbus RS-485 capabilities. When using this feature the drive can communicate with a
personal computer (PC), programmable logic controller (PLC), or other external device that utilizes Modbus
RS-485 serial communication for control or monitoring. Refer to the
smd Operating Instructions (SL03) for
connection details. Figure 1 illustrates the smd control strip. Terminals 7 (COM), 71 (TXB) and 72 (TXA) are
used for RS485 communication.
U V W
L1 L2
8 9 20 28 E1 E2 E3 K14 K12
+10
V
+12
V
COM AIN
7 71 72
L3
20 A1 62
TXA TXB
COM
Figure 1: smd Control Strip
2.2 Electrical Installation
2.2.1 Cable Type
For RS485 Modbus networks, use a quality shielded twisted pair cable. The use of low quality cable will
result in excess signal attenuation and data loss.
2.2.2 Connections and Shielding
To ensure good system noise immunity all networks cables should be correctly grounded:
• Minimum grounding recommendation: ground the network cable shield 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
smd control terminal, the unscreened cable cores should be kept as short as
possible; recommended maximum of 20mm. Ground the shield at the drive end only.
• In addition, grounding terminal 7 on the smd is recommended when using serial communications.
U V W
L1 L2
8 9 20 28 E1 E2 E3 K14 K12
+10
V
+12
V
CO
M
AIN
7 71 72
L3
20 A1 62
TXA TXB
COM
20mm
max
Connect to
drive earth
(PE)
Figure 2: Connector Wiring Diagram