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Relay Board Technical Support

Troubleshooting

The relay board doesn't respond to the relay test software?
Why doesn't the relay board work with HyperTerminal?
I can toggle the relays, but I'm unable to read the port status?

General Questions

All Boards

How far away from the PC will these boards operate?
Will the ECP software control a relay board using the repeat function?
Can the external transformer relay board be powered by my own DC supply?
The relay boards have a 9VDC input can they operate at a higher voltage?
What are the dimensions of the plug that is used for the DC power input?
Your specification states these are power relays can they be used as signal relays?
Do you have an enclosure available for the 1 & 2 channel relay boards like on the 8 channel board?
What are the advantages and disadvantages of the two transformer versions?
What is the wiring diagram for the modular adapter & cable?

8 Channel Relay Boards
Will two relays boards operate if they are set on the same address?
How far apart can the individual relay boards be from each other?

PCN Notices
1-2 Ch Power Supply Change
International RoHs Power Supply Change

Software Examples

Please note, due to the use of many graphics the following links to the code may be slow loading on a 56K connection.

Visual Basic

Visual Basic for Applications

If you need to control our relay boards, but do not have any programming experience you now have an option.  Our relay boards can now be controlled directly from a desktop shortcut using our command-line software.  

With this feature, a user can operate our serial relay boards without knowing any software programming language!

 

Troubleshooting Answers

The relay board doesn't respond to the relay test software?

First check to see if all the board address switches are OFF (board address A - 0000).  All boards are tested before they leave the factory, but the dip switches may have been left in ON position (address P 1111), after the testing was completed.  The relay test software defaults to board address "A" when it is loaded.

Check if you are using the wrong modular cable, the cable must be cross wired (normal telephone cable).  When holding both ends of the cable side by side, and the gold color terminals are facing towards you the same color wires should be on opposite sides.  See your instruction manual for a diagram.

If you are trying a used modular cable, the connections may also be bad.  Don't assume that if it works as a telephone cord it will work on a relay board, all the wires are not used in the telephone application.  Try a new cable.

Is the relay board connected to a different Com port then specified in the software?  The board is plugged into Com 2 when the software is looking for the device on Com 1.  You may also try the second serial port to see if the com port may be the problem.

If your using a very long cable the serial lines may have excessive noise interfering with the operation.  Test the board initially using a short cable to make sure it works.

If you are using a multiple channel serial board instead of the built in serial port, see if it works on the built in serial ports on the motherboard.  Some of the generic multi-port serial boards are of poor quality.

Why doesn't the relay board work with HyperTerminal?

Actually it will work with HyperTerminal, but not by typing in the commands.  Each character that is typed into the HyperTerminal window is transmitted immediately 'A'..., 'H..., one character at a time.  The relay boards require the command to be concatenated together 'AH1<cr>'.

 You can get around this problem by making a text file with notepad and placing the command you want to send on the first line of the file only -- as in turn ON Relay AH0 <cr> or AR0 <cr>, don't forget to press enter after the command to add the carriage return (<cr>). You will be able to read and write to the board to test it out.  Don't put more than one line in each file.  Use the >>transfer>>send text file command to send out the file on the com port.  Also note the board commands must be in uppercase.  Actually it's much easier to test your board using the convenient relay test software.

I can toggle the relays, but I am unable to read the port status?

First try using the relay testing software to verify that the board is working properly.  You need to manually transmit the codes at the bottom section of the software to verify the receive function is working properly.

When sending the read command "AR0" or any command for that matter, you may need to allow a slight pause between commands (10-30 milliseconds typically).  If you transmit the commands too quickly you will most likely overrun the serial input buffer on the relay board.  You need to slow down your software slightly.

General Questions

All Boards

How far away from the PC will these boards operate?

The RS232 specification lists a maximum of 50 feet between two devices.  The RS232 specification is usually much more robust than this limit.  In ideal conditions our relay boards operated properly up to 1000'  from the PC during testing.  This distance will not work in all environments due to noise factors from other sources, such us power lines, and other EMI/EMF emissions.  We have seen excellent results in noisy environments of 200-300' feet away from the PC.  We cannot guarantee that you will get the same results. When routing your RS232 serial cables keep them away from power lines and other sources of electrical noise.

Will the ECP software control a relay board using the repeat function?

Sure, the ECP (Event Control Programmer) software is primarily used to program our event control timers, but it can also be used to operate the 1, 2 & Eight Channel Relay Boards -- if you only need a timing function that operates continuously.  When using the 1 & 2 channel boards make sure the board address in the software is set to "A - 0000", the eight channel board may be set to any of the addresses "A - P".

Can the external transformer relay board be powered by my own DC supply?

Yes you can power one or more relay boards from a single DC Supply.  Make sure the supply has adequate power to exceed the combined power requirements from all boards.  The 1 & 2 channel relay boards both use a 300ma supply and the 8 channel board requires 1 amp of current for each board.

The relay boards have a 9VDC input can they operate at a higher voltage?

Yes all the relay boards can operate from 9-12VDC.  It's not recommended to exceed 12 volts.  The more you increase the voltage the internal power supply has to dissipate more heat which could lead to a failure.

What are the dimensions of the plug that is used for the DC power input?

The 1 & 2 channel boards use a 2.5 X 5.5 mm DC power connector.  The 8 channel relay board uses a 2.1 x 5.5 mm DC power connector.  The center pin is positive on all boards.

Your specification states these are power relays can they be used as signal relays?

These boards were designed for power applications up to 10 amp current, the relays that we use are Potter & Brumfield's and they are listed as a general purpose relay.  They will work properly in signal applications as long as it meets the minimum contact current as specified in the relay datasheet.  We have not tested the boards for cross talk in high frequency applications.  Please take note that the switching speed of the relay is not as fast as a reed relay, see the datasheet for info.

Do you have an enclosure available for the 1 & 2 channel relay boards like on the 8 channel board?

Yes we now have a machined enclosure to mount the 1 or 2 channel relay into (external transformer version only),  It fits the following relay boards only S1-RLY-EXT & S2-RLY-EXT.  The part number for ordering is RLY-ENC-EXT, it can be used to retrofit already purchased relay boards. Assembly is required.

What are the advantages and disadvantages of the two transformer versions?

The external transformer version is safe to use in an application where the board is used without an enclosure.  As an example you are controlling DC voltages using the relay board on a workbench, if you would use a internal transformer version the 120VAC is connect directly to the board and the terminal are exposed.  An external transformer version would be better suited in this application since low voltage DC is the only thing that is exposed.

If your controlling 120VAC in your application you should be mounting it in enclosure for safety reasons and the 120VAC is also available to power the board.  The 120VAC version is better suited in multiple board applications since it's easier to daisy chain the power to the boards.  If you were using the external wall transformer version you would need a lot of power strips to hook up say, 10 boards together.

What is the wiring diagram for the modular adapter & cable?

Below is the wiring showing the connections from the 9 pin DSUB on the PC to the input of the relay board.  Note the colors may be different than pictured.  This diagram is for the standard adapter (P/N ADP-MOD) , on some custom boards these may be wired differently.

8 Channel Relay Boards

Will two relays boards operate if they are set on the same address?

Yes two or more boards will respond to commands if they are set to the same board address.  The only problem you will have is if you want to read the status of the ports, each board would attempt to send data back to the PC at the same time and you may have a bus contention problem. Setting two boards to the same address will allow you to control two different circuits with one command.

How far apart can the individual relay boards be from each other?

The communication link between relays boards are also RS232 and the distance is the same as between the PC and the first relay board as explained here.

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