The HyperLink AL-D15P1228AW is designed to provide superior lightning and surge protection for RS-485 control and 12-28VAC power lines. These protectors incorporate individual protection circuits for the RS-485 control lines and AC power lines. All housed in one weatherproof resistant enclosure.

RS-485 Control Lines

A high power 3-stage design is used to provide protection for the RS-485 control line. The 3-stage design can handle higher-level transients than a protector that uses only diodes. The first stage is comprised of a differential gas discharge tube. Stage two is a pair of current limiting series resistors and the final stage is a low capacitance diode array. The use of three terminal differential gas discharge tubes provides superior common and differential mode protection against conducted transients versus the use of lower cost two terminal tubes. The second stage series resistance limits the power dissipation of the fast diode clamp array in the third stage. This allows time for the slower but higher power gas tubes to flash over. The diode array clamps the leading edge of fast transients to safe levels until the high power gas tubes turn on. This eliminates the damaging leading edge spike that single stage gas tube protectors let leak through. The diode array's low capacitance assures that the protector will not degrade the high-speed signals. The RS-485 control line is connected to the protector via its screw terminal blocks. The AL-D15P1228A