How can the ML24xxA be used in a Secure Environment?
Anritsu manufactures three families of power meters: the ML2400A/30A series, the ML2480A series, and the ML2490A series. This note details how information is stored on the power meters and how it can be removed for security purposes. All families have three different types of memory device in the power meter. Flash Memory: This contains the firmware for the main processor, the firmware for the DSP, the code for the FPGA (ML2480/90A series only), the instrument type, the options fitted and the serial number. It does not contain any user information or any variables generated during the execution of the code. ML2400A/30A has 1Mbyte, ML2480A has 2Mbyte, and ML2490A has 2Mbyte of Flash Memory. The user cannot write to this memory directly, and this memory is not accessible by the user. Volatile Static RAM: This contains the DSP execution code variables. This is initialized on power up and wiped clean when powered down. For the: ML2400A/30A (it is) Internal to DSP ML2480A (it is) 1Mbyte + internal DSP memory ML2490A (it is) 1Mbyte + internal DSP memory The user cannot write to this memory directly, and it is completely cleared during power down. This memory is not accessible by the user. Non-volatile Static RAM: This is a battery backed static RAM, which is used to store both the current instrument set-up, saved instrument set-ups and the main processor code execution variables. All of the user set parameters, such as the frequency used for the cal factor, the trigger time, and which sensor is connected, are stored in these set-ups. The following are the memory sizes for NVRAM in the associated power meter: ML2400A/30A 512Kbyte ML2480A 1Mbyte ML2490A 1Mbyte The user cannot write to this memory directly, but it can be completely cleared using the secure mode procedure (see operating manual or below description). The user can store and retrieve instrument set-ups in this memory. Security information such as the cal factor frequency needs to be removed from the power meter if the power meter is moved out of the secure facility. This can be accomplished very easily by using the Secure Mode on the Power Meters. This function enables the user to completely wipe the non-volatile static RAM of all information. How the Secure Mode Works: The user sets the secure mode on the power meter. When the power meter is next turned on, the non-volatile static RAM is completely purged of all information. The power meter then sets the factory defaults for the current settings. Clearing the Non-volatile Static RAM on the ML2400A/ML2430A Series: Press System /more /more /more and then Secure. Now press Secure again so that the top line of the display reads System SECURE state Clear memory. Now switch the power off and then on again. The power meter will now power up with the non-volatile static memory completely purged. The code execution variables are also purged at power on as well. The secure state can be set over the GPIB using the following command: SECURE ON Clearing the Non-volatile Static RAM on the ML2480/90A Series: Press the hard key System (LHS) and then Service (RHS) and then toggle Secure so that the green light is active. Now switch the power off and then on again. The power meter will now power up with the non-volatile memory completely purged. The code execution variables are also purged at power on as well. The secure state can be set over the GPIB using the following command: NVSECS ON For more information on the power meters, please see the relevant manuals or contact: firstname.lastname@example.org