[time-nuts] Schweitzer Engineering Labs SEL-2407 Satellite Synchronized Clock

[Gregory Beat]

Schweitzer Engineering Labs SEL-2407 Satellite Synchronized Clock
https://selinc.com/api/download/2909/?lang=en
There is NO GPS Disciplined Oscillator (GPSDO) with this Clock.  It distributes IRIG-B time codes.
1 PPS is an optional output from the clock. Newest version (300-series) costs $1,600 USD.
 
Their earlier 100-series SEL-2407 clock uses the Trimble 12-channel Larsen iQ GPS receiver (46240-20, Pb part), or the RoHs compliant part (46240-25). These 100-series Clocks will experience WNRO during 2024.
==
I obtained a Schweitzer Engineering Labs SEL-2407 Clock (100 series, 2005 mfg. date) in early February 2023, from a Rocky Mountain salvage company (paid far less than their asking price). They were unaware of a potential WNRO issue with this clock.
My purchase was a “Leap of Faith”.
 
Fortunately, SEL has update path for their older (100-series) SEL-2407 clock to address WNRO.
 
I successfully performed these update steps, earlier this month, to address the WNRO issue.
Schweitzer Engineering provided the support (manual and firmware files) that I needed.  
Since SEL serves the electrical power utility industry (post 9/11), their support take security pre-cautions (they are NOT structured for hobbyist support).
I performed my own research to find the correct Euro Terminal Plug (power), which was missing.
 
The SEL upgrade path requires a firmware upgrade (Trimble iQ to version 1.16) and a micro-code upgrade (internal FPGA to version 1.05) before 2024 (unit’s WNRO date).
IF the SEL-2407 clock is running the original v1.04 Trimble firmware, 
THEN an intermediate firmware upgrade to v1.05 is required before upgrading to v1.16.
==
IF you acquire one of these older SEL-2407 clocks and desire to perform this upgrade,
here are the REQUIRED Documents, Cables, Hardware, and HEX firmware files.
 
1.)   SEL-2407 Satellite-Synchronized Clock Instruction Manual (October 22, 2022 version, PDF, 41 pages). SEL-2407 Manual lists Specific Steps (page 35) to upgrade both GPS receiver and FPGA firmware.
 
2.)   SEL C234A Specific Serial (RS-232) Cable required to connect SEL-2407 (DTE) to Personal Computer (DTE). You will likely have to DIY Build this Null modem cable with proper CTS/RTS wiring.  Your personal computer needs a serial terminal program with XMODEM capabilities, to access the SEL-2407 Clock.  The PC serial port needs to support 115.2K (FPGA file is Large, 7.6MB).
 
3.)   The SEL-2407 uses a 6-position Euro terminal for Power and Alarm.  My unit was missing this Euro plug (Euro Terminal Block Plug, Green, 6-position, Straight, 7.62mm Pitch) as well as adjacent Green Ground Screw (Green, Hex Washer Slot machine screw, 6-32, 3/8” length).
 
PHOENIX CONTACT (Germany), Part Number: 1875140. Mouser and Digi-Key stock this Euro terminal block plug. ~ $20 each. My hardware drawer had 6-32 Hex Washer Slot Screw, and Testors GREEN Paint.
 
4.)   Acquire Three (3) HEX firmware files (Receiver, FPGA) to perform this upgrade.

5.)  Now you can begin the update process.
—
Connect C234A serial cable and GPS Antenna (TNC connector) to the SEL-2407.
 
Assure SEL-2407 is DISCONNECTED from Power.
SEL-2407 has an internal SMPS and DC-DC converter. Some steps during Upgrade Steps require Opening the Unit (Protection jumper for FPGA programming). DE-Energize SEL-2407 for serring the DIP switches !!
 
Go to Pages 8-11, Set the DIP Switches (front panel removal) for your Location and DST rules.
 
Attach SEL-2407 Clock to Power Source and Power ON.
 
Once the SEL-2407 has a Satellite Lock, use your computer to talk to the SEL-2407.
Commands are found on Pages 12-23 of the manual.

“STA” is the Status command, Page 21-22, displays Firmware and Status of your Clock.
 
Pages 32-39 cover the Steps for Upgrading the SEL-2407.
Have the HEX files in an accessible directory on your computer.
 
NOT Recommended for NOVICES or APPLIANCE OPERATORS.
Previous experience with upgrading embedded hardware & router firmware useful.
—
I can provide current SEL-2407 clock manual to an appropriate time-nuts repository.
==
 
Greg, w9gb
chicago