Technical Document

Free Contact). This could be from other relay contacts, thermostat contacts, alarm contacts etc. When
the contacts are closed the input will read as active. In fact anything that pulls the input pin down to 0v
will read as active. Do not think of the inputs in terms of a high or low voltage input. Think of it in
terms of Active (or on, something is actively driving the input), or inactive (or off, nothing is driving
the input). Command of 0x25 returns 4 bytes. The first 3 bytes are always 0.The two bytes returned
will be encoded with each bit corresponding to whether the input is active or inactive. A high bit means
the pin is being pulled low (active) by an external device pulling low.
Analogue Inputs
Eight (8) analogue inputs of 0v-5V at 10-bit resolution are provided. The conversion is performed
when you send the "Get Analogue Voltage" command 0x32 and the channel number. The resulting 16
bit integer will be transmitted back in two bytes (high byte first), combine these for the result. The 10-
bit conversion will be in the lower 10 bits of the 16 bit integer with the upper 6 bits being 0. There is a
5v supply available on the 3-pin terminal block between the analogue inputs .
Representative Analogue Input Schematic.
TCP/IP Password
If this option is enabled in the http configuration page then a password will be required to be entered
before relay states can be changed. In the following example the password was set to "apple":
0x79 - 1st byte in frame sent to ETH8020 to indicate password entry
'a' (0x61) - 2nd byte in frame
'p' (0x70) - 3rd byte in frame
'p' (0x70) - 4th byte in frame
'l' (0x6C) - 5th byte in frame
'e' (0x65) - 6th byte in frame