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Copyright ?2008, National Control Devices LLC

By Ryan Sheldon
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Mirror Modules:
Contact Closure Inputs and Remote Contact Closure Outputs
More than likely, you have sent me an email asking for a device that will send your contact closure inputs from one location to another.  Your not sure what to call these mysterious devices, and your not even sure if we have the kind of product you are looking for.  I get this kind of email several times a week, so it only made sense to answer your question in the form of an article so that everyone could benefit from a universally consistent answer.

The fact is, we have been getting this email question for several years.  And the short answer is, yes, we have EXACTLY what you are looking for.  We also have lots of combinations of devices to help get you started.  But for now, I want to start simple, and I will use this page to refer to several different products along the way so you know what I am talking about.

Just so we are clear, this page is about Mirror Modules.  A Mirror Module is a device that has a contact closure input.  When a change is detected on any of the contact closure inputs, a transmission is sent to a remote relay controller (often referred to as a receiver), which will mimic the inputs of the Mirror Module.  Here is a simple and popular example of products that get this job done using a wireless connection:


Here is an Example of a Popular Wireless Contact Closure Transmitter:
Code Name Image Price  
MIR8LRENC 8-Channel Mirror Module with RS-232 + LR Series Transmitter 8-Channel Mirror Module with RS-232 + LR Series Transmitter  $109.00
Here is an Example of a Popular Wireless Contact Closure Receiver:
Code Name Image Price  
R85W1LR Remote Wireless Relay Switch 8 Channel 5 Amp SPDT 10KBPS Long Range 1-Way Relay Controller Board Remote Wireless Relay Switch 8 Channel 5 Amp SPDT 10KBPS Long Range 1-Way Relay Controller Board  $164.00

Click Here to see all the Compatible Wireless Contact Closure Receivers

In the example above, you will connect up to 8 switches directly to the blue connectors of the Mirror Module.  When a change is detected on any of the 8 switches, a Radio Data Transmission is generated to activate the corresponding switch on the receiver.  For instance, if you turn on the switch connected to input 1 on the Mirror Module, Relay #1 will turn on at the remote location.  Similarly, if you turn on a switch connected to input #5 on the Mirror Module, Relay #5 will Turn ON on the remote receiver.

As you may have noticed, there are only 8 inputs on the Mirror Module, so it would be better to use a receiver that has 8 or less outputs.  If you use a receiver that only has four outputs, then Mirror Module inputs 1-4 are the only ones that will have any effect on the receiver.  Inputs 5-8 on the Mirror Module won't do anything.

Another popular combination is below:

Code Name Image Price  
MIR8LRENC 8-Channel Mirror Module with RS-232 + LR Series Transmitter 8-Channel Mirror Module with RS-232 + LR Series Transmitter  $109.00
R45W1LR Remote Wireless Relay Switch 4 Channel 5 Amp SPDT 10KBPS Long Range 1-Way Relay Controller Board Remote Wireless Relay Switch 4 Channel 5 Amp SPDT 10KBPS Long Range 1-Way Relay Controller Board $124.00

 

Frequently Asked Questions:
Q)  Can I Have More than One Transmitter Talk to One Receiver?
A)  Yes.  When a radio transmission is made, every controller within range will respond by default.
 
Q)  Can I Have Several Transmitters and Receivers Paired Together in One Location without Interfering with Each Other?
A)  Yes.  You can pair a transmitter so it only works with a specific receiver or a specific group of receivers.  This is done by configuring the transmitter to transmit specific keys along with its data transmission.  Each receiver must be programmed to accept specific keys.  The following device MUST be used to configure Keys into receivers:
Code Name Image Price  
AC418LR AirControl 418MHz Long Range Wireless Command Transmitter for LR Series Controllers AirControl 418MHz Long Range Wireless Command Transmitter for LR Series Controllers  $89.00
 
Q)  Can I Send Contact Closure Inputs to a Computer?
A)  Yes.  Wireless Data from the Mirror Module can be received by a computer using the following device:
Code Name Image Price  
AM418LR AirMonitor 418MHz Long Range Wireless Traffic Monitor AirMonitor 418MHz Long Range Wireless Traffic Monitor  $94.00
 
Q)  What if I Need more than 8 Contact Closure Inputs?
A)  No Problem, we have two options for you.  You can either expand the 8-Channel Mirror Module with More Inputs or you can use a Mirror Module with more built in inputs.  Your choice, they work exactly the same way.  Here are you product options:
Expand the 8-Channel Mirror Module with More Inputs:
Code Name Image Price  
USCS16 Ultra Series ScanSwitch 16-Channel Contact Closure Detector Expansion Module Ultra Series ScanSwitch 16-Channel Contact Closure Detector Expansion Module  $55.00
USCS32 Ultra Series ScanSwitch 32-Channel Contact Closure Detector Expansion Module Ultra Series ScanSwitch 32-Channel Contact Closure Detector Expansion Module  $95.00
USCS48 Ultra Series ScanSwitch 48-Channel Contact Closure Detector Expansion Module Ultra Series ScanSwitch 48-Channel Contact Closure Detector Expansion Module  $138.00
Mirror Module with More Built In Inputs (Can Still Be Expanded)
Code Name Image Price  
MIR32LRENC 32-Channel Mirror Module with RS-232 + LR Series Transmitter 32-Channel Mirror Module with RS-232 + LR Series Transmitter  $134.00
  
Q)  How Far Can I Transmit with Wireless Communications?
A)  We have Tested our Wireless Communications at 3,000 Feet in an outdoor environment, direct line of site with minimal RF interference with excellent results.
 
Q)  Do Mirror Modules use 1-Way or 2-Way Communications?
A)  Only 1-Way Communications is Currently Supported.  But it is a lot more reliable than you might think.  The Mirror Module supports a setting we call Reps.  When you configure the Mirror Module, you can specify how many times data is transmitted to the remote device.  The remote device only has to pick up ONE of these communications to be successful.  A value of 10 usually yields a very good range and can operate at a distance of over 2,000 feet.  However, the maximum distance of 3,000 feet is rated using a Reps value of 255.  Which means every time a contact closure input is detected, 255 data packets are generated.  This takes 2-4 seconds to complete.  A smaller Reps value will yield faster communication while a larger Reps value will yield longer communication range.
 
Q)  How Fast is it?
A)  This depends on the Reps value (explained above), but is usually less than 1 second, but can take a few seconds.
 
Q)  What About False Relay Triggers?
A)  We use a data encoding method that prevents relays from "accidentally" firing.  Data must fit a very specific format, and must be complete (including an 8-bit checksum), for the command to be processed.
 
Q)  Can a Mirror Module be Battery Powered?
A)  Yes and No.  Mirror Modules were not designed to operate from a battery, so they have no power saving features built in.  However, is you can provide a 12VDC supply, it can be powered for a while, as the device only consumes a maximum of 100ma.  It is also possible for us to build a 5V version of the device, which could run off 3 AA batteries for a couple of hours.
  
Q)  What if I Don't Need Wireless Communications?
A)  No Problem, ALL Mirror Modules are capable of RS-232 Communications, and are Compatible with ALL NCD RS-232 Relay Controllers.  Communication Range is well over 1,000 feet at 9600 baud.