AC112Q-3, AC125Q-3, AC150Q-3, and AC165Q-3 Operations Manual.... 38
It is strongly recommended that an RS-232C optical isolation be included in any RS-232C/SCPI
protocol integration to avoid the creation of ground-loops and ground-fault paths through the
remote communication port; such isolation is not included with the standard product.
6.5
REMOTE COMMUNICATIONS, cont.
6.5.2 RS-485/Modbus
If included in the converter, a Modbus Option converter/optical-isolator will be located adjacent
to the RS-232C serial port (see Figure 4 on page 19).
The Modbus Option included converter/optical-isolator connections are depicted in Figure 7
below.
Figure 7: RS-485 CONNECTIONS