RadiMation Application Note 123

Implementing the control of a switch matrix in RadiMation^®

This application note describes how to support a switch matrix into RadiMation^®, in such a way that the actual relays are correctly controlled when the automated test is performed by RadiMation^®

When making a test setup it can be needed to switch to different equipment for different settings or frequency ranges. This is supported in RadiMation^® by being able to make a specific driver for a switch matrix to be used in a specific test-site.

Normally the actual physical configuration of one or more relays and the related cabling and connections is available as a schematic drawing or listed in for example a Microsoft Excel sheet. It provides which components are connected to each other when the relays are in a certain state. SPDT (single pole, double throw) relays normally can be in two modes, being: 'Normally Open' (NO) and 'Normally Closed' (NC). Other relay types like SP6T (single pole, 6 throw, or a one on 6-relay), indicate a specific switch state with the actual position number.

• 'Normally Closed' (NC) indicates the state of the relay when it is completely un-powered, and thus is the state in which it returns when it is being disconnected.
• 'Normally Open' (NO) indicates the connection that is made when which is opened (not connected) when the relay is completely un-powered. To make a connection on the 'Normally open' state, the relay has to be actively controlled.

Based on these state, and the actual physical switch matrix design the exact flow of the signals is known, and it can be determined which switches need to be set to create the desired signal path.

An radiated immunity test with two frequency bands

To activate a desired signal path, switch matrix device drivers with the correct settings need to be selected in the test site.

A simple possible scenario where a switch matrix can be used is the automation of a Radiated Immunity system that has different amplifiers and different antennas to cover the frequency range from 80 MHz up to 3 GHz. The equipment that can be used for this is:

Test site	device type	model	frequency range
Radiated Immunity - 80 MHz - 1 GHz
	Amplifier	ETS-Lindgren 8100-002	80 MHz - 1 GHz
	Coupler	Bonn BDC 0110-40	100 kHz - 1 GHz
	Antenna	Schwarzbeck VULB 9160	80 MHz - 1.7 GHz
Radiated Immunity - 1 GHz - 3 GHz
	Amplifier	Bonn BLMA 1030-250	1 GHz - 3 GHz
	Coupler	Bonn BDC 0530-50	500 MHz - 3 GHz
	Antenna	Schwarzbeck BBHA 9120D	1 GHz - 18 Ghz
Generic / used in both
	Signal generator	RadiGen RGN2006B	4 kHz - 6 GHz
	Forward power meter	RadiPower RPR2006C	9 kHz - 6 GHz
	Reflected power meter	RadiPower RPR2006C	9 kHz - 6 GHz

Apart from this equipment also two power meters to measure the forward and reflected power are used. A single signal generator is used to drive the amplifiers.

See the picture below for a schematic overview of this setup. In this diagram the cables for the forward power are drawn in red, while the cables for the reflected power are drawn in blue.

The signal path and devices needed in the different bands need to be different, while at the other hand some equipment (like the signal generator and power meters) are the same for both signal paths. To configure the differences, it is necessary to make two test sites. The first test site is for testing on the the low frequency range and the second test site is for testing on the high frequency range. During the actual test configuration, the desired test site for the frequency range can be selected that is applicable. And because the test site configuration also contains the correct switch matrix configuration, also the relays will be automatically set to create the correct signal path.

This switch matrix design can now be implemented in RadiMation^® by configuring the different components. In this example, separate switches are being used, however it is also possible to use switchboards that have more then one relay, and in that case a single switchmatrix device driver for each test site can suffice.

Configuring and using switches in RadiMation

Now that you have thought out your design we can configure RadiMation.

Configuring the switch

First start with adding the switches and configure them correctly. Below you will see a picture of the device driver switch matrix:

We will show one example in detail. For the other switches, the process is the same. For explaining purposes I will use the switch design shown in the schematic drawing.

If we look at the first device in the switch design we see that we need to be able to switch between the two amps available in the system. We want to use the amplifier suitable for low frequency for the tests from 80 MHz - 1 GHz (AMP1). For the range 1 GHz to 3 GHz we need to switch to the amplifier for the higher range 1.0 GHz - 3.0 Ghz (AMP2).

Looking at our switch-design we see that AMP1 is Connected to the normally closed output of the switch. Amp2 is connected to the normally open output of the switch. Now we have the data we need to set the drivers up correctly.

First make two drivers for the switch settings for AMP1 and AMP2.

Go to device drivers and click Add.

Change the description to a name that reflects the connection.

Do not configure it yet, but make a second switch matrix for AMP2.

Now we know that we have made the drivers for our two settings of the switch we can configure it.

Go to device drivers and open the switch we just created for AMP1. Go to Advanced.

Select the correct protocol and configure it. Now go to the tab Switches.

We are now configuring the switch for AMP1. When we look at our switch design we see that we need the switch to be in Normally Closed. As the switch I have used in this example only has on relay we set Relais A to Normally Closed.

Following this steps you have now made a driver that can be used to switch the signal of the system to the input of AMP1. To finish our example we have to do the same for AMP2.

Go to Device drivers, select Switch matrixes and select the switch matrix that we have created for AMP2. Open the driver and go to advanced.

Set the communication on the communication tab. This will be the same as the previous driver as we are communicating to the same device. We only want it to switch the relay to Normally open. Make sure that you set this on the Switches tab.

Using the switch in your test-site configuration

Now that we have made the drivers, named and configured them we are ready to implement them in our test system. For now I will stick with example used above. In this case two test sites will work well to set the path correctly for the low and high range.

Go to Test-sites, and click on Add to make a new test-site, also providing it with a logical name like for example: "Radiated Immunity - 80MHz - 1GHz"

Now add all the devices needed to perform the test. In this case that would be the amplifier, signal generator, power meters and an antenna. To make sure that the switching is done correctly we need to add the drivers for the switch matrixes.

If we look at the switch matrix design we know that we need to set the signal generator signal to the right amplifier and make sure that the powermeters are using the signal of the right coupler.

In the case of this example this means that I need to add three switches. If a switch matrix has more relays, one switch would have been enough as you can set all the relays from the same driver. Below you see the picture of the test site made for the low-end path.

Below we have done the same except that it was for the high path. You can see that it resembles each other however the switches are set correctly for the range by selecting the correct test site.

Normally Open: The connector of a relay that is not connected to the common connector of the relay if the relay is not powered

Normally Closed: The connector of a relay that is connected to the common connector of the relay (and thus closed) if the relay is not powered

The ability of an EUT to be immune to incoming electromagnetic interference. This is equivalent to the term susceptibility that is used by some standards.

The ability of an EUT to be immune to incoming electromagnetic interference. This is equivalent to the term susceptibility that is used by some standards.