Relays

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The IB1004 + SB1004 has two low-power mechanical relays.

These relays can only handle relatively light loads -- they are rated for 24V/1A. If your load is inductive in nature, then the power the relays can handle may actually be several times lower.

Relay outputs

Relay outputs are on terminal block #4. Both normally closed and normally opened lines are provided for each relay.

 

Terminal #

Function

9

Relay 2, normally opened line

8

Relay 2, normally closed line

7

Relay 2, common line

6

Relay 1, normally opened line

5

Relay 1, normally closed line

4

Relay 1, common line

3

Serial port: RX (RS232); TX/RX+ (RS485)

2

Serial port: TX (RS232); TX/RX- (RS485)

1

SYSTEM (COMMON) GROUND

Relay control

Two lines of the EM1000 (located on the NB10x0 network board) control the relays. On power up, all EM1000 lines are configured as inputs and pulled up internally, keeping relays off. To turn the relay on, set the corresponding control line LOW. Naturally, you need to configure these GPIO lines as outputs in order to be able to control the relays.

 

Line

Function

Corresponding

EM1000 I/O

IC1000 cable line

RELAY1 (output)

Relay 1 control:

HIGH (or input*) - relay off

LOW - relay on

GPIO36

22

RELAY2 (output)

Relay 2 control:

HIGH (or input*) - relay off

LOW - relay on

GPIO37

20

*GPIO line configured as input (default state)