For any BrightSign units with USB or TTL Serial Port

8 Inputs, 8 '10 amp' Relay Outputs

USB-8I-8R-HC (High Current)

Features:

• Footprint (4.8 x 5.3 inches)
• 8 Inputs (for logic interface or switches)
• 8 Output Relays for Lamps or Relays (10 amps each relay)
• 12V required (external power supply) for the relays
• on board LED's to indicate Power and Processor running.
• Serial Setup: 38,400 baud, N,8,1 (standard serial communication)
• The Board has built-in 250AC snubber networks (works with AC or DC)

Outputs:

The Controller (BrightSign or other controller) has to send a single byte to control the 8 relays.  The bits of the 8 bit byte controls the 8 relays.

At any time, the Brightsign sends out the 'Set Port Byte', then the relays will turn on according to the bit pattern of the 'Port Byte'.  I.E. Bit 0 of the byte set to '1', will turn on Relay1.  Bit 7 of the byte set to '1' will turn on Relay 8.

I.E. To control the relays, send the byte that represents the bits of the relays (see table below).  The single byte turns on/off the relays according to the bits!

• Bit     Binary              Decimal
• 0       00000001b      1d
• 1       00000010b      2d
• 2       00000100b      4d
• 3       00001000b      8d
• 4       00010000b      16d
• 5       00100000b      32d
• 6       01000000b      64d
• 7       10000000b      128d

Just add the decimal numbers together to get the bits set that you want.  Setting all bits on is 255d (decimal).  Setting bits 0 and 7 on is 128+1 or 129 decimal

 The Relays have a terminal Block for connections (no bus)

DC Voltage 'Large Inductive loads' may require a diode to be placed across the load.  Without the diode, the inductive 'kick' when the relay is turned off can reset the microprocessor! AC loads require a snubber network across the contacts of the relay on the HMS board.  The board has built in snubber networks AC/DC loads.  The snubber networks may be insufficient for preventing reset when driving highly 'inductive' DC loads such as a 'contactor relays' or a motor.

Inputs:

As inputs are closed, a string representing inputs 1 to 8 is sent (2 bytes).  I.E.  "1",13 (ascii 1 followed by a carriage return for input 1 closure.  This way the BrightSign will respond to the inputs after a carriage return.

When all inputs are released, a 'zero string' is sent.  I.E. "0",13 (ascii 0 followed by a carriage return

Author: Richard Harkey
Revised: August 17, 2024