Software
The relay boards can be used with almost any software language that is able to use the PC
RS232 serial port. The relay board recognizes standard ASCII characters that are transmitted
from the host computer. Commands are case sensitive.
A H 1 <cr>
Board
Identification
Board Command
Relay
Number or Data
“<Board Identification><Board Command><Relay Number or Data><Carriage return>”
Board Identification
The Board ID is “A” For the
single or dual channel relay
boards, these boards will only
respond to this address.
Board Commands
H = Relay HIGH (ON)
L = Relay LOW (OFF)
R = Read relay status
W = Write data latch
M = Momentary Delay
T = Toggle relay
Relay Number or Data
(H or L) = Relay number 1 or 2 or 0
to turn ON all relays on the selected
board
(R) = receive a number 0 – 3
(W) = write a number 0 - 3
Board identification:
The board address is the first part of the command sent to the relay board it is set to “A” in
firmware and may not be changed for the single and dual channel relay boards.
Board Commands:
The board command is the second part of the serial data sent to the relay board. These
commands work in conjunction with the third part of the serial data that will be explained in
the following section.
H= Relay High (ON) – Sending an “H” will direct the board to turn ON the relay (making a
connection between the NO & COM contacts on the board).
L= Relay High (OFF) – Sending an “L” will direct the board to turn OFF the relay (breaking
the connection between the NO & COM contacts on the board).
W= Write data latch – Sending an “W” will write directly to the port. This command allows
you to turn multiple relays ON or OFF on the same board at the same time.
R= Read relay status – When this command is sent to the board, the board will respond back
to the PC with a decimal number, which corresponds to the status of the relays on the board.
This will be explained in more detail below:
M= Momentary Command – This command will briefly activate or deactivate a single relay
or all relays. The initial state of the relay will determine whether the relay toggles ON – OFF
– ON or OFF – ON – OFF. The momentary delay default is 30 milliseconds, but may be
changed from 10-50 milliseconds in the setup.
T = Toggle command - The toggle command will reverse the relay from it’s current position.
The initial state of the relay will determine whether the relay toggles ON or OFF.
Relay Number or Data:
The relay number or data command is the third part of the serial data that is sent to the relay
board(s) - this data is numerical. The data that is sent or received will relate directly to the
board commands that were explained in the previous section.
If the board command is “H” or “L”:
Send a number 1 or 2 which represents the relay number on the board and will turn ON or
OFF the individual relay specified. Sending a zero that will turn ON or OFF ALL relays
on this board.
If the board command is “W”:
Send a number from 0 to 3. When this number is converted into binary, it represents the
relay numbers on the board. This command allows you to turn multiple relays ON or
OFF at the same time with one command. Binary data is one’s and zero’s which
represents ON and OFF on the relay board (ON = 1 & OFF = 0). See table #1
Plug in the wall transformer or apply power to board (on-board transformer). Make sure the
board address in the software is set to “A”. This is the software default and is used in a single
or dual channel board configuration. Click ON #1 relay in the software program and there
should be an audible click from the relay selected, and the LED will illuminate.
NO
C
NC
N/L2L1
Ch1
Copyright (c) 2008 Pencom Design, Inc
2CH- RLY
T1
RS-232 IN
NO
C
NC
Ch2
GND
PC
Ground
Line
Neutral
Line or
Posi tive Voltage
Device to
Control
NegativeorNeutralW ire
Modular cable
Modul ar cable adapter
connected to the serial port
Figure2
Connecting Relay Outputs
At the right side of the board as shown above you will see one or two 3-contact terminal blocks
marked with NC, COM, NO these are the relay outputs. Relay channel numbers are marked
next to each terminal block. Warning do not touch any other components on the board since
static electricity from your fingers may damage these devices.
Strip the insulation back on your wire approx. ¼ inch. Wire the hot (or positive if DC) side of
the power to the COM pin, and the output to the device under control using the NO (normally
open) or NC (normally closed) pins depending on your application. Insert the stripped wire
into the side of the terminal block and tighten the screw to clamp the wire in place. The
terminal blocks are designed for 14-22 AWG wire size. Do not exceed the 10 amp current
rating of the relays. Most applications will use the normally open contacts. See the relay
datasheet available for download from our website.
Modular Cable Wiring
When routing modular cables, do not place them next to power cables as this will induce noise
on the lines and could cause RS232 communication problems.
Important use only reversed wired modular cables in Figure 3, NOT network/printer/data
cables-- that are straight wired which may damage the boards as shown in Figure 4. Note in
Figure 3, when you hold the modular connectors together on both ends of the wire with the
gold pins facing you the same color wires are on opposite sides (the color doesn't matter only
the position).
See figures 3 & 4 below to view diagrams of wiring differences:
DO NOT USE
Figure 4
Straight Connection for network or data use only
CORRECT
For Relay Boards
Figure 3
Reverse Connection for normal telephone lines.
Pencom Design, Inc. 2 Pencom Design, Inc. 3 Pencom Design, Inc. 4
Transmission distance, PC to relay Board:
Standard RS232 specifications 50 feet, minimum.
Relay outputs:
10 Amp 240VAC/28VDC SPDT 1 form C power relays.
Operating Temperature & Humidity:
0º to 70º Fahrenheit, 90% Relative
RoHS Compliant: Only units with a “-O” suffix in the part number.
Parts Listing
All Models Include:
1 – Custom wired RS232 9 pin Dsub to Modular Cable Adapter
(Part number: ADP-MOD)
1 – RJ-11 Modular telephone cable (reverse wired)
Part Number MC4-7.
Model: S1-RLY-INT & S2-RLY-INT
With internal power transformer 120VAC 50/60 Hz with terminal block connection.
Model: S1-RLY-INT-2 & S2-RLY-INT-2
With internal power transformer 230VAC 50/60 Hz with terminal block connection.
Model: S1-RLY-EXT & S2-RLY-EXT
1 - AC to 9VDC Wall Transformer adapter
Setup Instructions
Important: make sure you use the proper modular cables (reverse wired) when connecting the
relay board to the PC. A 7’ cable is supplied with the unit, but some customers require longer
cables to extend the distance from the PC. If you intend to extend the distance from the PC
purchase the cables with your unit to assure correct configuration.
Connect the computer, RS232 Modular cable adapter, modular cable, relay card, and wall
transformer as shown in Figure 1. If you have the internal transformer version reference Figure
2. Note if your version has a 230VAC input transformer connect one side of the 230V power
to L1 and the other side to L2/N on the terminal block, ground wire is connected to GND.
Note only one output connection is shown on the drawing although this is a dual channel unit.
The relays can control an AC or DC voltage.
PC
Modular cable
adapter
connec ted to the
serial port
Modular Cable
Figure 1
Wall
Tranformer
NO
C
NC
Ch1
Copyright (c) 20 08 PencomDe sign, Inc
RS- 232 IN
NO
C
NC
Ch2
Line or
Pos itive Voltag e
Devic e to
Control
Download, install, and run the relay test software on your Windows based personal computer.
Select the correct COM port in the software that’s connected to the relay board. The Relay
Test Program operation is explained in the help file.
