Cole-Parmer Instrument Company
Manufactured by:
Barnant Company
Page
12 of 24
Power Supply
The primary power supply for the system is a 115 VAC or 230 VAC +/- 15%, 50
or 60 Hz, wall outlet. The rear panel power input module for the detachable power cord
contains the fuse. Switch SW1 on the Main PCB selects between 115 and 230 Vac
operation, so that the same PCB can be used for both voltages.
An unreg24 Vdc supplies power to the analog inputs and outputs, to the
relays K1 through K4, and to the +5 Vdc switching regulator U13, which supplies power
to the rest of the control circuits. The unreg24 Vdc is generated by filtering
(C49) a full-wave rectified (D22-D25), center-tapped secondary winding output of T1. A
double isolated transformer T1 is required to avoid ground loops and for safety, as the
remote inputs and outputs might provide an electrical connection to an energized
surface.
+5 V Switching Regulator
Shown below is a schematic representation of the U13, LM2594, +5Vdc
switching regulator circuit. In the figure, C1 corresponds to C49, L1 to E24, C2 to C53
and C62, D1 to D27 L2 to L4, and C2 to C55 and C56. The remaining components are
internal to U13. Circuit waveforms are shown in the figure following.
Barnant Company
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28W092 Commercial Avenue
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Barrington, IL U.S.A. 60010-2392
847-381-7050
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800-637-3739
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847-381-7053 (Fax)
e-mail:
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Web Site: http//www.barnant.com
