Specifications

2. EXPLANATION OF OPERATION
Item n°. : W1404621 Page 2-4 Version 01.02
2.2. Automatic cutoff
The MAGSCREEN is supplied by an external box through the control of MAGLIFE C PLUS.
The "automatic cutoff" board realize the supplies communication system according to the
signals given on the optical cable from the MAGLIFE C PLUS.
The main voltages +12V, -12V and +5V arrive from the connector J3 (D8). They are protect by
fuses F1, F2 and F3 (D6). The capacitors C6, C7 and C8 (C7) are present to delete the
electromagnetics radiations.
The signal coming from the MAGLIFE C PLUS. (serial link) and transported by an optical fiber
is send to U1 (B8). This circuit convert the optical signal into an electrical signal. The signal
obtained in this way is shaped by U2C, U2B and U2D (B6) circuits to be integrated and sent to
the PC interface (via J1 (B1)). The integrator is built around U2A (C4) ; C4 and R2 (C5)
determines the time base of the supplies cutting delaies (about 30 s).
The supply communication system is built around transistors T1,T2, T3, T4, T5 and T6. T1
(C3) amplify the U2A output to control the +5V and +12V voltage switch. T2, T4 and T6 (C2)
commutate the +5V voltage ; T3 (C3) commutate the +12V. U3 (B3) and T5 (B2) commutate
the -12V voltage.
F
Remark : U3 is supplied by the +5V commutated voltage. Consequently,
the -12V voltage can only be present when the +5V voltage is
commutated