ProStar325 Service Manual
76
Publication date 8 May 2003
4.2.3
Visible lamp power supply
The visible lamp supply is a continuous current buck converter
operating at 200kHz. One side of the lamp is connected to +24V
and the other side is regulated to be 12V down from that supply.
U56 is a current mode controller. Q10 is turned on by the
controller, causing the current in L5 to increase. Q10 is turned
off by either a maximum current (as sensed at pin 3 across shunt
R352), or a voltage over 2.5 volts on pin 2. When Q10 switches
off, the flyback spike is clamped to +24V by D39.
U45 is a differential amplifier that provides the correct feedback
voltage to U56. This results in a lamp voltage of 12.1 VDC.
Diode D40 couples the VISON# signal to the feedback pin (U56
pin 2) to force the device to the off state when VISON# is not
asserted.
U46 compares the average current in shunt R352 to a fixed
reference. This is used to report that filament current is flowing
(lamp lit).
4.3
Processor PWB
The Processor PWB contains all necessary photometric signal
processing and I/O devices to control the instrument and any
accessories.
Operating conditions and results are transferred between the
instrument and host computer by an Ethernet TCP/IP interface.
The computer has ultimate control over the system and is
responsible for issuing commands to the instrument and
accessories. The instrument interprets these commands, carries
out the required actions, and reports the results.
The Processor PWB is a fibreglass board with eight layers of
tracks and power planes, using surface-mount technology (SMT).
Component-level repair is generally not possible and is not
recommended.
If you have a need to attempt to unsolder/solder components, use
caution as damage to any of the through-holes (“vias”) would be
very difficult to repair.
There are SMT components on the rear of the board that may be
damaged if they catch on objects when the board is being
handled.
Electro-magnetic compliance (EMC) issues
OK
Return an error
StockCheck.com
Summary of Contents for ProStar 325 UV-Vis
Page 9: ...ProStar325 Service Manual Publication date 8 May 2003 9 S t o c k C h e c k c o m ...
Page 19: ...ProStar325 Service Manual Publication date 8 May 2003 19 S t o c k C h e c k c o m ...
Page 34: ...ProStar325 Service Manual 34 Publication date 8 May 2003 S t o c k C h e c k c o m ...
Page 71: ...ProStar325 Service Manual Publication date 8 May 2003 71 S t o c k C h e c k c o m ...
Page 72: ...ProStar325 Service Manual 72 Publication date 8 May 2003 S t o c k C h e c k c o m ...
Page 118: ...ProStar325 Service Manual 118 Publication date 8 May 2003 S t o c k C h e c k c o m ...
Page 149: ...ProStar325 Service Manual Publication date 8 May 2003 149 S t o c k C h e c k c o m ...