Firmware update V 1.06.01 (2021 June) made the following changes:

1. Changed connection timeout from 100 mSec to 1 Sec to correct connection timeout errors on low latency connections.
2. Changed default scan count from 1 (single shot) to 0 (Infinite), by default instrument will now scan continuously until user stops it.
3. Changed default Auto Record from OFF to ON, instrument will by default record data.
4. Default measurement rate was changed from Custom/NPLC to Medium. User can change back to Custom/NPLC if needed for their application, but medium is always the default after an instrument reset.
5. Corrects an issue with user defined Alarm and Timestamp configuration getting lost.

Note: Users of 2680A-APSW V6.03 should also update to version 6.04 to complete to coincide with 1) above. The 6.04 update can be downloaded from the 2638A product page.

Note: To update to V1.06.01 in the field your current Firmware version must be 1.03 or above. Units with versions below 1.03 must be returned to Fluke for updating.

Note: 2638A User’s Manual Supplement Issue 1, Date 6/21 was released with this update and applies to all instruments.

1. Prepare a USB memory stick (1 mb to 32 mb in size) on this memory stick create a folder named “firmware” (case sensitive, all lower case) Place the two attached files in this folder (Auxinfo.txt and mtv.flt)
2. Insert the USB drive to the 2638A and wait until the RED led is lit (this means the drive is ready). Note: some USB sticks cannot be read by the 2638A so make sure the USB LED turns solid red if you are using a new USB
3. Press the [Instrument Setup] button
4. Select [Firmware] and press soft-key F3 – [Edit]
5. Press F1 – [Update firmware]
6. File copy process will start, please wait until it is finished. Do not interrupt power, touch any panel buttons or address the unit by remote command during this process. Doing so may render your unit unusable requiring a return for service.
7. After the new firmware file is loaded, the instrument will reboot by itself. This may take a few minutes.
8. Go to the instrument setup button to confirm the new firmware is correct.

Main Version 1.04 (2016 February)
Add: Corrects calculations when using temperature constants (1586A)

Firmware 1.03
Add: Enables firmware updates by using the instrument USB port