A3016 and MAO test at CAEN

Pigi, A. Boaino & CAEN

Test Schema

1. MAO 48 service from BC2. EASY 3000 – Joint 48 Power & Service

3. Dummy LinkBoard load: R & C4. Output power from A3016:– 2.5 Volts / 5.0 Amp– 3.5 Volts / 10.0 Amp

• MAO output current = 5 A– With a A3009 board more = 17 A

MAO

SY1527

48 service

3-phase

EASYA3016

48 service48 power

load

What powering OFF the MAO in the proper ways ?

• Powering OFF the MAO via SY1527 or using the interlock placed on the front

What powering OFF the EASY in a “bad” way ?

• Powering OFF the EASY 3000 crate removing the power or service connector from the back

What cutting the MAO 3-phase ?

• Shutting-down the MAO cutting 3-phase

•oscillation does not depend from the MAO load (from 4 A to 18 A)

•sometimes 2 oscillations in few msec

•oscillation disappear separating the 48 power from the 48 service

•No other ways to reproduce it

What happen cutting MAO 3-phase ?• MAO goes OFF in 2 steps: a first from 48 V to 22 V and a second

from 22 V to 0 V (slower)• A3016 channels are switched OFF in 200 msec after 600 msec

from the MAO shut-down (software delay to be sure that was not a voltage oscillation)

A3016 switched OFF

48 V

2.5 V Step #1

Step #2

When and why the oscillation is generated cutting the MAO 3-phase ?

• The oscillation on the A3016 output is generated when the MOA output cross 22 Volts

• An oscillation has been seen when Vcc goes from 12 V to 6 V and this produce the spike.

Vmao = 22 V

Vcc = 12 V

6 V

How prevent this spike during a MAO power-cut ?

• We can prevent the oscillation and spike separating the 48 service and power of the EASY crate as suggested by the CAEN since long time.

• To do that we need to modifying the cable routing and have a dedicated MAO under UPS to generate the 48 service.

• A faster solution is the put a “big” capacitor between the 48 power and service in order to give a couple of second more to the service and let the EASY crate switching off in the proper way.

• A capacitor of 33 mF + a protection diode are ok

Results with C and diode

power

service

1.5 sec

Results with C and diode

2.5 V

48 VNo spikes or oscillations

600 msec

Conclusion on the MAO

• MAO cannot reboot itself even in case of “bad” shut-down.– Need to clear the status alarm to switch back it.

• In case of SY1527 reboot the MAO and the LV channels stay OFF until a “clear alarm”

• CAEN recommends to use 2 different lines for the power and service of the EASY crates.

Conclusion on the A3016• The LV board has been designed as a general purpose board, for

ALICE, ATLAS and CMS– The output feedback circuit has not been optimized to supply the link

board (one crate has a large input capacitance) • Let me remember you that Link Baord does not have any regulator

or protection on the power lines to reduce the power dissipation.• Oscillations have been detected during the switching ON of the

channels and have been partially cured via firmware we still need to work on that and on the 2 channels sync.

• An oscillation has been detected, during the last week test at CAEN, on the A3016 channels in case of improper shut-down of the MAO (3-phase cut)– Can this oscillation break the Link Board ?– How can we can solve this problem and all the other possible problems ?

Conclusion on the A3016Long Term Solutions:

1. Designing a protection on the LB crate LV lines2. Designing a “special” output feedback circuit of the A3016 for the

link board

Temporary Solutions:• Working on the firmware in order to reduce problem during the

switching ON• Synchronize the switching ON of the 2 independent channels via

firmware (now is via PVSS)• Separating the 48 service and power of the EASY

– OR

• Introducing a big capacitor (33 mF) between the service and power line of the EASY:– Solution has been successfully tested at CAEN– It does not have any side effect on the system

Action Items

1. Capacitor test at 904 and eventual installation2. Definition of the synchronization requirements

and ramping-up sequence.– two channels at same time ? How many steps ? How

long the sequence ?

3. Official request at CAEN of a new “firmware” to develop and test asap and CMS validation.

4. Design of the LV lines protections