5
2.0
、
Internal connection
：
C. Internal connection
From left to right the terminal is:
1
、
“RS485” is RS-485 interface
：
“A” “B” are RS-485signal A
and signal B
。
2
、
“POWER” and 4~20mA output interface
：
“4~20mA” is
4~20mA signal output
，
“VDD” is 24V positive terminal, “GND”
is 24V negative terminal
；
3
、
“ALARM”
：
connect with 24V audible-visual alarm
，
if
choose the 200~1000Hz frequency signal, it could be frequency
output interface.
4
、
“K1” is relay output
：
Grade-I alarm interface, when the signal
up to Grade-I value, relay K1 will act and control fan or other
equipments.
5
、
“K2” is relay output
：
Grade-II alarm interface, when the
signal up to Grade-II value, relay K2 will act and control fan or
other equipments.
