CONV-TTL-RS485 v4.0 tests
Prior to launching production for 320 CONV-TTL-RS485 boards, tests were carried out with the two possible RTMs, the CONV-TTL-RTM-RS485-OPT and the CONV-RS485-OPT-RTM boards.
For GMT (General Machine Timing) reception, the main criteria for testing was to ascertain correct reception of these frames by the CTRV (the CERN VME timing receiver board). The CTRV is able to check the timing frames received, and signals errors in terms of missed timing messages, and in terms of its own PLL being able to lock to the signal received.
Signal distribution in optical
Test description*
- Lab bench measurements
- Optical distribution of timing frames through 10km fibre.
Test results* CTRV signals no errors in received frames and no PLL errors after about a week of continuous reception.
Signal distribution in copper
Test description*
- Soft lab measurements
- Copper distribution of SPS timing frames through 1.15km copper VH4 cable.
Test results* CTRV signals no errors in received frames and no PLL errors after about a week of continuous reception.
Taken on July 10th, this screenshot above shows no pll errors or missed
GMT frames have been recorded with long cable distribution
Mixed copper/optical distribution
Test description*
- CERN installations, with existing distribution network including multiple hardware modules and legacy repeater hardware.
Test results* CTRV signals no errors in received frames and no PLL errors after about 7 weeks of continuous reception (From May 22/05/2018)
Conclusions
The conv-ttl-rs485 board is in its 4th version. It has been tested in various configurations even before the tests detailed before. Though more tests are required for the optical RTM, the motherboard itself has performed well during testing and no more modifications in hardware are needed. Production can therefore be launched.
Denia Bouhired - July 10th, 2018