ICP DAS USA GW-7552-B User Manual page 12

slave in a local RS-485 network. Depending on whether the gateway acts as a
Modbus master or as a Modbus slave and on the number of devices connected to
the RS-485 network device the four jumpers provided by the module has to be
set according to Table 6. The jumpers set the pull high and pull down resistors
for the RS-485 port (Figure 9).
Figure 8 RS-485 connection
Table 6 Jumper position for the RS-485 port
Pull high/low resistor
GW-7552-B / GW-7552-M PROFIBUS/MODBUS GATEWAY User Manual (Version 1.60, May/2017) PAGE: 12
GW-7552-B/GW-7552-M
RS-485 Port
Enabled
(default)
Disabled
RS-485
Condition
 The GW-7552-B / GW-7552-M is
the master in RS-485 bus or
 the number of devices connected
to the RS-485 bus is less than 10
 The GW-7552-B / GW-7552-M is
a slave in RS-485 bus or
 the number of devices connected
to the RS-485 bus exceeds 10