Pending revised versions for EMC/CE :
LKAT2 Issue/Design Updates
Noise 3/'15 converted to EMC version
U3 stress 1/'16 factory test changed
Soft AD 2/'17 snubber fix
U3 chip 2/'19 sn1902... new, more rugged U3 implemented
WtBoard 11'19 sn 19110003+
IP improve 9/'20 sn 20090033+ ( FE earlier )
6w DC/DC 7+/ '21?
LKAT2 Narrow-Bus Addendum
more current bus mountin drawings :
LKAT2 Head size limit to P1+P2 1020max ( SIGMA 930max )
NOW 2040mm ( remember chamber limit of 1200mm per side )
( 6w version avail but bigger, redesign corner PCB required )
Std version: MU power supply : rated at 1.25A at 12V out ( 1.2A available for the head )
Head Half DCconv : rated at 0.325A at 12V in = 5v 0.6A output ( 3w )
ASIC consumption 7,5mA/chip with 1chip per 15mm
Limit: 1020mm/15mm = 68chips x 0.0075a = 0.51amps/head half
Limits : 1020mm head half consumes 0.51amps ( DC converter limit is 0.6A ) --> OK
Max DC/DC draw is 0.325A x 2 = 0.650A ( MU power limit is 1.2A ) --> OK
SIGMA ver: MU power supply : rated at 1.25A at 12V out ( 1.2A available for the head )
Head Half DCconv : rated at 0.325A at 12V in = 5v 0.6A output ( 3w )
ASIC consumption 7,5mA/chip with 1chip per 15mm
Limit: 1020mm/15mm = 68chips x 0.0075a = 0.51amps/head half
Limits : 1020mm head half consumes 0.51amps ( DC converter limit is 0.6A ) --> OK
Max DC/DC draw is 0.325A x 4 = 1.3A ( MU power limit is 1.2A ) --> NOT OK
Simple limit calc = 1.2/1.3 = 92% x 1020 specified limit = 938mm --> 930mm
4-segment Using a SIGMA approach to utilize 4 head segments ( like LKAT2p but connect to sigma MU )
Simple calc 2 head sides ( one width and one height would be limited to 930mm x 2 = 1860mm )
so lets say H + W < 1800mm
PENDING LKAT2 MAXIMUM HEAD SIZE LIMIT DETAIL and work-around
Common : MU power supply : rated at 1.25A at 12V out ( 1.2A available for complete head = 14.4w )
Head Corner DC/DC : Input : 0.325A at 12V = max output of 0.6A at 5V = 3w (77% efficient)
ASIC consumption 7,5mA /chip with 1chip per 15mm ( RJM actually measured only 6mA )
STD/OEM MU power supply : for 2 active corners, 7.2w available for each / 12V = 600mA available for each
Head Corner DC/DC Howeveralthough 600mA is available, max accepted is 325mA
325mA @ 12V in = 600mA @ 5V out
ASIC consumption : 600mA / 7.5mA per chip = 80 chips
P1 + P2 limit 80 chips x 15mm per chip = 1200mm total P1+P2
Standard "L" head is limited by the DC/DC converters in the 2 head corners
SIGMA : MU power supply : for 4 active corners, 3.6w available for each / 12V = 300mA available for each
Head Corner DC/DC 300mA @ 12V in = 554mA @ 5V out
ASIC consumption : 554mA / 7.5mA per chip = 74 chips
P1 + P2 limit 74 chips x 15mm per chip = 2 heads at 1110mm total P1+P2 each
SIGMA is limited by the power supply in the metering unit
Port / OEM-4 Maximum side, ie P2 Head Corner DC/DC 325mA @ 12V in = 600mA @ 5V out
ASIC consumption : 600mA / 7.5mA per chip = 80 chips
P2 Absolute max : 80 chips x 15mm per chip = 1200mm for P2
These P2 sides draw 325mA x 2 = 650mm from 12V in metering unit
This leaves 550mA / 2 = 225mA for each of the P1 sides
Max P1 (if P2=1200mm) Head Corner DC.DC 225mA @12V in to Corner DC/DC = 415mA @ 5V out
ASIC consumption : 415mA / 7.5mA per chip = 55 chips
P1 max if P2-1200mm 55 54chips x 15mm per chip = 810mm for P1
P1+P2 can not exceed 2010mm or an individual P1 or 2 length of 1200mm
LKAT2 TEST INFORMATION (RJM etc.Apr'17) (Complete EMC docs in Tech Bull)
In-Process Tests: All PCBs are function tested independently before being assembled
Head sensor and head 'corner' PCBs are function tested independently before assembly
Head, Mains, Signal cables are tested for short circuit and open circuit
Assembled Metering Unit function tested
In-Process : Complete, assembled System Function test and 'coarse' setup
Internal supply and head channel voltages checked
In-Process : Measuring Head Conditioning, Stability and identification of weak components
System is energized and then thermally cycled while measuring actual bus current
Automated repeating cycle of 180minutes at -15C and 120 minutes at +65C ( transisition time of 20 )
Total duration is 100...200 hours
In-Process : Insulation / Hi-Pot test
Measuring Head : 10kV DC for 1 minute ( we have tested heads up to 13.5kVDC per worksheet )
Measuring Head Cables : 1.5kV DC for 1 minute ( engineering has tested 1m at 15kV for 1min )
In-Process : Final Configuration and Calibration
System configuration checked against worksheet
System calibrated to match worksheet and published specifications
Type Testing : External Laboratory for EMC
EN61000-3-2,-3 Harmonic Current Emissions and Voltages Fluctuations
EN61000-4-2 Electrostatic Discharge Immunity
EN61000-4-3 Radiated. Radio-Frequency Electromagnetic Field Immunity
EN61000-4-4 Electrical Fast Transient/Burst Immunity
EN61000-4-5 Surge Immunity
EN61000-4-6 Immunity to Conducted Disturbances Induced by Radio-Frequency Fields
EN61000-4-8 Power Frequency Magnetic Field Immunity
EN61000-4-11 Voltage Dips, Short Interruptions and Voltage Variations Immunity
Some key Type tests for insulation: ( includes head on bus to 25kVDC )