Description of the PCB

[A]

mini-USB connector

[B]

CR2032 battery

[C] 

Button to reset default settings (factory settings)

[D] 

Restart button

[E]

RUN/SERVICE switch

[F] 

RUN LED

[G] 

SERVICE LED

[H]

Optional Wi-Fi or Ethernet board connector

[I] 

Buzzer

[J]

Loop activity LED

[K]

Loop terminals

[L]

Primary power-supply terminals

[M]

Ancillary power-supply terminals

[N]

I/O1, I/O2 terminals

[O]

Relay terminals 1

[P]

Relay terminals 2

[Q]

Relay terminals 3

[R]

Relay terminals 6

[S]

Relay terminals 5

[T]

Relay terminals 4

[U]

I/O3, I/O4 terminals

[V]

Functional earth terminal