SATEC EM920 Installation Manual - Manual (Page 22)

Chapter 16
Communications options
The EM920 has several communication alternatives depending on your ordering
preferences. All communications ports, of different type, can be used simultaneously
.
The basic EM920 is equipped with one standard optical communication port (COM1), an
optically isolated RS-485 communication port (COM3) and an USB Device Type A.
Other COM ports are available as optional module.
On Board Communication port
Infrared Communication port (COM1)
Mount an optical probe cable (not included), at the instrument front panel, to communicate
between the meter optical port and a PC serial port
Figure 19: Infrared Communication port – COM1
RS-485 Communication port (COM3 – on board)
The RS-485 Communication port – COM3 is provided by the LOGIC/DISPLAY board.
The RS-485 connection is provided by the LOGIC/DISPLAY cable with three wires as shown
in figure 18
Figure 20: Serial Communication Network Connection – RS-485 COM3