For any BrightSign units with USB or TTL Serial Port

16 Relay Outputs

USB-S3-16R

Features:

• Footprint (4.8 x 5.3 inches)
• 16 Output Relays for Lamps or Relays (6 amps each relay)
• 12V required (external power supply)
• on board LED's to indicate Power and Processor running.
• Serial Setup: 38,400 baud, N,8,1 (standard RS232 communication)
• The Board has built-in 250AC snubber networks (works with AC or DC)
• Series 3 compatible 'Serial' or USB

Operation:

The Controller (BrightSign or other controller) has to send 2 bytes to control the 16 relays.  The bits of the two 8 bit bytes control the 16 relays.

At any time, the Brightsign sends out the 'Set Port String', then the relays will turn on according to the bit pattern of the 'Port Byte'.  I.E. Bit 0 of byte1 set to '1', will turn on Relay1.  Bit 7 of byte2 set to '1' will turn on Relay 16.

I.E. To control the relays, send the two bytes that represents the bits of the relays (see table below)

• 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

Note: This board utilizes the typical HMS 'Break' Protocol.  That is, after 10 milliseconds if inactivity (break), the serial 'counter' resets to zero.  Then the next byte received is byte 1, then byte2

Note: If byte 2 is not sent, then byte 1 will be processed.  Relays 1-8 will be turned on or off per the bit pattern of the byte.

Note: See the schematic for the use of the 'bus' connections.  Bus lines are present to use the board 12 volts for easy connection to drive external loads.  Or, 120VAC/240VAC can be applied to the bus and then jumpers made (soldered) to connect the bus voltage to the relay contacts.

Note: RE: Inductive Loads (external relays or long wires).

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 for this purpose.  The snubber networks may be insufficient for preventing reset when driving highly 'inductive' DC loads such as a contactor relay or motor.

TT compatible:  The 3.5mm stereo jack can be used with the BrightSigns that have a TTL serial port. The on-board regulator provides the 5V to power the board logic when using the TTL port for interface.

Auto Polarity: ('AUTO-POL' sticker on the board) firmware has autodetect for the serial polarity.  The board configures the serial polarityconnection automatically for the USB or TTL connection.  If using USB you need to send a null byte [serial.sendbyte(0)] to synchronize the board serial polarity.

Author: Richard Harkey
Copyright © 2009 HMS Electronics. All rights reserved.
Revised: March 02, 2024