ModuleDiagnostics

No response

1. Is the module power on?
2. Is Icc above 100mA? If not, no module is connected.
3. Is Idd above 450mA? If not, the module has no clock.
4. Is Icc above 900mA? If not, the module has not been configured.

For any of the above, check that the configuration database matches physical reality: cables, fibre mappings, module serial numbers. Also check that the VCSEL interlock has not been activated.

• Lv trips on rampup
  • Problem - (mostly old SCTLV2 and LV3?) LV can trip when trying to ramp up without clock, ie with lasers off.
  • Solution - turn on lasers (go to configured state on run control) before turning on LV.
• Module wont configure - TX problem
  • Module continues returning clk/2 (i.e. 50ns clock).
  • Diagnosis either by tools->SctApiGui?->Probe returning 2
  • Diagnosis (alternative - Scope) tools->SctApiGui?->RodDiagnostics?->set link to front panel to RX channel.
  • Have you connected the correct TX fibre to the module?
  • Solution - it may be that the PIN diode is current-saturated. Check that the voltage drop on the PIN bias is less than about 0.5V. If not turn down the laser current (TxCurrent?).
• Module returns junk - RX problem
  • Diagnosis as above, but with "J" rather than "2" in the probe, or scope.
  • Solution - adjust RxDelay and RxCurrent? (perhaps by doing BocSetupTests), until a good signal is received. [Note that in release 3 doing these tests suggests values but a restart is needed afterwards, before doing digital or analogue tests.]

Also the SctApiGUI has an auto-configure function which should suggest fibre-swaps if it can work them out. This isnt 100%, but is worth a try!

Miscelaneous Queries

Q. My module is sending short events in response to the triggers sent during the RX threshold test. What might possibly be wrong?

A. It could be that the module configuration is set to read out less than the full complement of chips, however you'd probably know about that already. So the most likely explanation is that one or more chips has powered up in an error state. This can be confirmed by running any standard scan with on ROD scan control, such as an NMask test. If any chip is stuck in an error state, the scan will abort right away. To recover, try send the module a hard reset. (If DIM/DDC is not working, do this from the power supply console.) To avoid this problem in the future, power on the modules in two distinct steps, typically STANDBY to ON, before the clock is enabled. The power on reset circuit may not function correctly if a slow ramp is used.

See also SoftwareDiagnostics