Inovance MD500 Series - Page 243

8. Peripherals and Options
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Extension RS485 Card (MD38TX1)
MD38TX1 is specially designed to provide the drive with RS485 communication function.
It adopts isolation scheme and electrical parameters conform to international standard. It
helps to implement control of drive running and parameter setting through remote serial
interface.
485+ 485- CGND
J
3
J2
Table 8-13 Terminal descriptions of MD38TX1
Type Terminal Terminal Name Function Description
RS485
communication
terminal
485+ RS485 positive input RS485 communication terminal with
isolation input
485- RS485 negative input RS485 communication terminal with
isolation input
CGND RS485 Power ground Isolated power
Table 8-14 Jumper descriptions of MD38TX1
Jumper Description Meaning Setting
J3 RS485 terminal resistor
matching selection
Matching the terminal resistor
Not matching the terminal resistor
Note
Setting of jumpers takes top view with main terminals at the bottom of the
card as visual angle. Jumpers are silk-screened on the card.
● RS485 bus topology
The RS485 bus topology is shown as follows:
485+
485-
CGND
485+
485-
RS485 bus
CGND
MD500
MD38TX1
MD500
MD38TX1
Set J3 to
match terminal
resistor
485+
485- CGND
485+
485- CGND
J3
Master
slave 1 slave N
J3
terminal
resistor
120Ω
terminal
resistor
120Ω