RadiMation Application Note 114
How to measure data from the EUT using the Configurable AD Convertor device driver
This Application Note explains how the Configurable AD Convertor can be used to monitor an EUT. With the AD convertor, any type of signal can be monitored and plotted within RadiMation during an immunity test.
The configuration can be separated in two steps:
- Configure the Configurable AD Convertor device driver to retrieve the value from the measurement device.
- Plot the measured value during an immunity test using the correct unit.
Configuring the Configurable AD convertor
Create a new Configurable AD Convertor device driver. It is best to give this new device driver a descriptive description to identify it clearly for the task that it is used for. After the device driver is created, open the 'Advanced' settings window of the new device driver.
Specify the communication type
First the correct settings for the communication with the measurement device must be configured. The Configurable AD Convertor supports several communication types, which can be used to communicate with the measurement device. Depending on the connection that is used, select the correct Communication Stream, and configure the parameters correspondingly to communication settings that are used by device.
Configure the commands for the initialisation of the device
The Configurable AD Convertor device driver has several boxes, in which remote programming commands can be specified, which should be transmitted to the measurement device on defined moments.
Reset | The reset code that needs to be transmitted to device. When left blank, no command will be transmitted. |
Init | The command that is transmitted to initialise the configured device. When left blank no command will be transmitted. |
Get ID | The query-command that is transmitted to retrieve the ID of the device. This is used to check if the device is connected. A commonly used SCPI command is: *IDN?. When left blank, no command will be transmitted. |
Wait for Completion after sending command | If the checkbox is ticked, RadiMation® will wait for all the commands to complete, before it continues. This is achieved by also transmitting the SCPI query-command '*OPC?' to the device, and waiting for the response. |
Configure the measurement and interpretation of the measured value
AD convertors can have multiple channels from which values can be read. The Configurable AD Convertor device driver is able to retrieve the values from up to 40 different channels from the measurement device. For each AD channel, an individual query-command can be set, specific for the measurement value that should be retrieved.
The configuration of a single channel can be configured on one of the specific 'Channel <nr>' tabs.
Trigger | The trigger query-command can be specified to trigger and request a new measurement value from the device. A commonly used SCPI query-command is: 'READ?'. |
Read Back | Different measurement devices will return the measured value in different formatting. The configurable AD convertor is able to determine the numeric value of the measurement device response by using regular expressions. The text in the Read Back box, is used as the regular expressions to determine the numeric value in the response of the measurement device.
The regular expression for finding the first numeric value (including fractional and scientific notation) in a text is: ([+-]?[0-9]*\.?[0-9]+([eE][+-]?[0-9]+)?) The part of the regular expression that is contained in the round brackets, is retrieved as the measurement value and converted to a numeric value. For more possibilities see the Read Back examples section. |
The minimum and maximum measurable value of the measurement device can be specified to correctly scale the measured value. This will also be used to re-calculate the retrieved measurement value to another value with another unit.
Minimum value | The lowest value of the channel that can be measured with the controlled measurement device. The value must be the same as filled in the EUT window. |
Maximum value | The highest value of the channel that can be measured with the controlled measurement device. The value must be the same as filled in the EUT window. |
It normally is the best to configure the Minimum value to 0, and to configure the Maximum value to 1.
Read Back examples
Received information | Regular expression | Determined measurement value | Note |
---|---|---|---|
U_L_N 325 | (-?[0-9.,Ee-]+) | 325 | Takes the first number. |
I_L1;12.34 | ;(-?[0-9.,Ee-]+) | 12.34 | Takes the first number after ";". |
THD_U_L1;;14,5 | ;;(-?[0-9.,Ee-]+) | 14.5 | Takes the first number after ";;". |
AC_FREQ;Channel1;1.23E3 | ;.*;(-?[0-9.,Ee-]+) | 1230 | Takes the first number after the appearance of a second ";". |
The correctness of the regular expression can be tested and improved by using the Validate Expression tool.
Plot the measured value during an immunity test using the correct unit
Create a new monitoring input channel
- The monitoring functionality is applied to the EUT. Therefor we first need to have an EUT file opened.
- In the opened EUT file, we can select the Monitoring input channels tab.
- Double click an existing input channel or add a new input by using the add button.
- A new window will open to configure the monitoring input channel.
Configure a monitoring input channel
- At the device menu, the newly configured AD convertor can be selected.
- The selected AD channel must be selected.
- The Unit type can be specified as text.
- With Calculation, the raw value from the AD convertor can be modified to match the preferred unit. More information can be found here.
- The Monitoring Input channel description will be shown in the graph title.
- After pressing Ok to save the configurations, ensure that the configured monitoring channel is marked as Active in the monitoring input channels list.
Running a test
When an immunity test is performed, RadiMation will also measure the value from the measurement device and it will plot the line(s) of the activated monitoring input channel(s). By switching to the Table tab, the measurement values will be shown in a tabular style.