The order does not matter. However, Do NOT power off the Master crates (rack B620B-26 bottom crate).
The oder does not matter for EMT and GLT crates. But it does matter for DCZ crates!
The crates are labelled in the order they should be turned on - the master crate has the label "first, check I'm turned on", the TSF-X crate is labelled "1", the TSF-Y "2" and the BLT/ZPD crate "3".
Failure to follow this order might result in DCZ not being able to configure and a possible error message in CMlog would be "Damage 0x4000 from node 3 crate 0x40000000 slot 2". This is caused by interuption in DCZ clock. If the timing to the DCZ clock is interrupted, the TSF's can be in a funny state; therefore the DCZ front end crates need to be power cycled.
DCZ Crate Power-up sequence after power outage or glitches at IR2-EH
- Master crates and DCZ ROMS (rack B620B-26 bottom crate)
- TSF-X crate (rack B620B-25 bottom crate)
- TSF-Y crate (rack B620B-25 top crate)
- BLT/ZPD crate (rack B620B-25 middle crate)
Image of DCZ crates
Other crates (EMT, GLT) Power-up sequence
- GLT crate: rack B620B-24 middle crate (there are 3 crates, top, middle, bottom)
- EMT crate: rack B620B-21 bottom crate (there are 2 crates, top, bottom)
Some Situations that require power-cycling DCZ Crates
If in doubt, contact the Trigger commissioner.
- If the master/ROM crates were powered off/on or fiber pulled, you need to power cycle the DCZ crates (#2,#3, #4 above). To do this, go to the B620B-25 rack, switch off all three crates and then switch them back on IN THE ORDER according to the label next to the switches, namely: the bottom TSX crate first, the top TSY crate second, and then the middle DCZ crate last. Failure to do so might result in timing/framing problem in data, or not being able to configure DCZ.
- The DCZ ROM is known to be flaky, and it needs power cycled. In this case, you also need to power cycle the DCZ crates (repeat step #2, #3, #4 above). An indication of this is the link B "ready" red light on in slot 2 (in rack B620B-26 bottom crate), in which case DCZ is failed to configure.