david macnair power supply [email protected] 3/30/20061 ethernet power supply...
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David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 1
Ethernet Power Supply Controller
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 2
Ethernet Power Supply Controller(EPSC)
The EPSC was intended as a replacement for the PEP 2 Bitbus Power Supply Control chassis
The intent was to provide as much commonality as possible with the Bitbus controller
The performance was to be equal or better then the Bitbus chassis
Should not cost more then Bitbus controller
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 3
The main components to be changed
The DAC used in the Bitbus chassis is obsolete and a new DAC was required.The Bitbus network is obsolete and it is desirable to convert to Ethernet (10/100 Mb/sec over UTP)The FPGAs are at end of life and are not good choices for new designsThe 8044 processor is obsoleteUse standard +/-15VDC power supply
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 4
The main features to preserve
Size of controller (1U in 19 inch rack)Power Supply, Transductor, and Interlock connector types and interfacesUse Bitbus Daughter BoardsSupport Bitbus command setUse existing Bitbus local control boardSupport for redundant transductorAll interlocks handled by FPGA, not softwareAbility to reset processor without turning off power supply
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 5
Desirable improvements
Improved speed and resolution of ADC
Internal Fan to allow true 1U stacking
Air Filter and closed chassis to minimize dirt
Provide option of analog or digital regulation
Magnet Interlock circuit to locate faulted klixons in magnet strings
Extended analog readbacks
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 6
Power supply controller functions
Precision current regulation (using PS as voltage source)Setting and ramping of currentsReadback of current, voltage, and ground currentGround fault protectionHardware magnet and power supply protection (no software)Fault latching and reportingSimple low cost serial communication to central control
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 7
Interface to Standard Components
Power Supplies of many ratings, types and from different vendors
Board range of current transducers (transductors)
Standard cables (Cat 5 UTP and D-sub computer cables)
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 11
Current Input Daughter Board Voltage Input Daughter Board
> 600 amp Transductors150, 300, and 600 amp Danfysik Transductors
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 12
Local Control Board
Allows Local control of Power Supply
Voltage or Current Regulation
Analog Test Points
Same as Bitbus Local Controller
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 13
Processor board
Uses 32 bit Motorola Coldfire processor
512K of flash program memory
8M of SDRAM memory
Provides Ethernet interface and 3 UARTS
C Libraries and Compiler
Boot loader over Ethernet
TCP/IP stack
Real time operating system (uCOS)
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 15
Sigma Delta ADCs
Two Burr Brown ADS1255
24 Bit Sigma-Delta ADC
6 PPM linearity (corrected to 2 PPM)
Input amplifier provides +/- 12V range
20 bit effective resolutuion of 10V range at 60 samples/sec
Gain set by oven stabilized zener (0.25 PPM/C)
Gain and offset readings interleaved with data
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 16
DAC (PWM)
8 bit PWM
32 MHZ clock
117 KHZ period (274 clocks)
9 clock minimum ON/OFF period
24 bit input latch
Forth order digital filter
Output regulated using ADC1
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 20
Analog and Digital Regulation
4 modes of operation
Error Amplifier with DAC reference
Error Amplifier with Local Control reference
Direct PS control with Local Control
Direct PS control with DAC, digital regulation using processor and ADC1
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 22
Klixon Fault Location Circuit
Allows klixon fault location in strings of up to 40 klixons
Two circuits per controller
Three wire interface, no active components in radiation areas
Controller senses current in interlock chain after a fault, converts to conductance to locate faulted klixon.
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 24
Fan Speed Control
Fan voltage programmable from 5V to 13V
Speed changes from 3000 to 9000 RPM
Voltage at minimum below 90 ° F
Voltage at maximum above 105 ° F
Fan filter on front panel of controller
Fan RPM calculated from current pulses
Air ducted below PC board
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 26
Current Status
2 Prototype units built
4 Pre-Production units built
40 Production Units under construction
30 units for SSRL
7 units for LCLS injection
David MacNair
POWER SUPPLY CONTROLLER [email protected]
3/30/2006 27
Comparison of Bitbus and EPSC Controller Performance
Bitbus EPSC Unit Parameter
2 30/60 ADC readings per second
12 3 uV RMS ADC noise (0.1 to 10 Hz)
18 20 Bits Effective number of bits (10V FS)
21 24 Bits DAC resolution
* 2 uV RMS DAC noise (0.1 to 10 Hz)
* 2 PPM max DAC Linearity 0-10V
0.25 0.25 PPM/°C max ADC temperature stability max
1.0 1.0 PPM/°C typ Daughter card temperature stability
typ
