Post on 04-Jan-2016
description
ICS – Software Engineering Group
1
SNS Power Supply Control
Sheng Peng
ICS – Software Engineering Group
2
Overview
Power supplies are from different vendors» IE power, Danfysik, Alpha …
Power supplies have different capability» +/- 20 Amps, +/- 35 Volts stackable» +525 Amps, +35 Volts» +400 Amps, +20 Volts» +375 Amps, +80 Volts» +390 Amps, +24 Volts» +700 Amps, +18 Volts» +900 Amps, +51 Volts» +1300 Amps, +95 Volts» +1405 Amps, +390 Volts» +4000 Amps, +18 Volts» +6000 Amps, +440 Volts» +185 Amps, +27 Volts» +1400 Amps, +800 Volts» +2200 Amps, +33000 Volts» +20 Amps, +75 Volts» +40 Amps, +75 Volts» …
Uniform control interface for most of power supplies» SNS Power Supply Controller (PSC)/Power Supply Interface (PSI)» EPICS based software
ICS – Software Engineering Group
3
Revisons
PSC» 6U single wide VME board for operation» 1U rack mounted for PSI test and calibration» PSC based function generator (RHIC only)
PSI» 1U rack mounted for rack mounted/standalone power supply» 6U single wide VME board for VME-style power supply» “Higher speed less ADC” PSI (Under development in RHIC)
ICS – Software Engineering Group
4
Power Supplies in SNS
ICS – Software Engineering Group
5
Automated Power Supply Test and Calibration
ICS – Software Engineering Group
6
PSC/PSI Software
ICS – Software Engineering Group
7
PSC/PSI Hardware
PSI and VME with CPU and PSC
PSC
PSI
CPU
ICS – Software Engineering Group
8
PSI
ICS – Software Engineering Group
9
PSC/PSI in SNS
PSC/PSI is the SNS standard interface to every power supply
PSI (Power Supply Interface)» Installed with every power supply» One 16-bit DAC with jumper selectable Unipolar/Bipolar mode» Four 16-bit ADCs» Self calibration» 15 bits digital out with selectable static or 100ms pulse mode» 16 bits digital in» Fiber link to PSC, 9-pin analog connector/37 pin digital
connector to power supply PSC (Power Supply Controller)
» Customized VME board with serial port available» Fiber link to PSI» Support 6 power supplies per board» 128K circular buffer per channel to save 5458 samples» Software or hardware triggered read/write up to 5KHz» Burst read up to 10K samples/second (BNL is upgrading it to
100K)
ICS – Software Engineering Group
10
Communication Protocol/Real-time performance
CPU PSC» Communicate thru VME bus backplane» All registers are memory mapped» Large circular buffer holds read back» Typical VME access cycle is 0.5~1.0 µs/word
PSC PSI» Multimode fiber with SC connector» 5MHz carrier, upgradeable to 50MHz» Each frame consist of 1 start bit, 1 byte frame ID, 3 bytes data,
1 byte CRC and 2 stop bits. So 43bits(8.6µs)/Frame in total.» Setpoint/command needs only 1 frame (plus 1 echo)» Readback needs 7 frames (1 request, 6 response)» Whole write action takes ~20µs (include DAC setup time)» Whole read action takes ~80µs
ICS – Software Engineering Group
11
Portable Power Supply Test Stand
ICS – Software Engineering Group
12
Long Term Reliability Test Stand
Each VMEHas 4 PSC’s
Each RackHas 24 PSI’s
Running at up to 4000Hz for several months
Many 10^12 messages without CRC or timeout errors.
ICS – Software Engineering Group
13
Electrical performance (Some test results)
Fiber interface provides the best electrical isolation ADC Reading Accuracy
ICS – Software Engineering Group
14
Some Test Results ADC Linearity Test
» Approximately 1-bit (300uvolts) variation from –10v to +10v input.
ICS – Software Engineering Group
15
Some Test Results
ADC Temperature Stability
300uvolts = 1 bit
Approximately ½ bit change with 10 degree F change in temp.
ICS – Software Engineering Group
16
Cost
There are two choice to get PSC/PSI» Buy as COTS from Apogee Labs» Get design then have a manufacturer to build it
PSI» RHIC built it recently with a small amount: $895 each» RHIC built revised PSC with a small amount: $1600 each» Apogee Labs ask for $2854.50 (~$2000 for BNL) per board
with the order more than 100 boards» Assume we buy PSC from Apogee Labs and build PSI like
RHIC did, the cost will be $895 + $2854.50/6 = ~$1380/PS» If we build PSC too, the target cost should be ~$1150/PS
ICS – Software Engineering Group
17
Status
In use at NSRL and SNS» DC power supplies 100ppm accuracy» 60Hz triggered read/write
Preliminary use at IHEP» planned for BEPC-II
Under evaluation for other BNL applications
Design owned by BNL
EPICS S/W freely available
ICS – Software Engineering Group
18
Summary
PSC/PSI combination can be a cost-effective solution
H/W is proven reliable
H/W design is “open”
EPICS S/W is available
User community is growing