Forward Proton Detector Pot Movement Control Hot Lines

Figure 1 shows a schematic for the Power Control Adapter, that is used
as one for each FPD station, dipole or quadrupole, as indicated in
Figure 2.

![](media/image1.wmf){width="5.699305555555555in"
height="2.8229166666666665in"}

Figure 1 -- Pot Movement Control Adapter

![](media/image2.wmf){width="6.31875in" height="2.245833333333333in"}

Figure 2 -- Pot Movement Control General Scheme

The hot line switches, Emergency switch that is normally closed (NC) and
Driver switch that is normally open (NO), are in a panel in the Control
Room. Do not ground these lines at the FPD Control Room, they should be
isolated there because they are grounded at the FPD rack +5 V power
supply. They are connected through green RG58 coaxial cables to the FPD
Power Control Adapter, a little box with a passive circuit that helps
the Roman Pots movement control in the following way:

1 -- The emergency line go to the Index Interface board, home input.
When the switch closes we have home input at ground, 0 volt, so the IIB
understands that nothing need to be done to move Roman Pots to home
position. But when the switch opens or the cable is broken the home
input goes high to +5 volts, due to R1, and the IIB send all the Roman
Pots to home position. The reason for this logic is that the probability
to happen a short circuit to in the cable is much smaller than an open
circuit. The FPD Power Control Adapter uses the same +5V the FPD Index
Interface board -- IIB.

When IIB home input goes high D3 send Driver Box input 1 high to +5
volts, enabling the drivers. D3 and D2 form AND circuit for emergency
line and driver line signals.

2 -- Opening the drivers switch or if an open circuit happens in the
cable then the Driver box is off and the Roman Pots will not move unless
the emergency switch opens. When the drivers switch closes the +5 volts
go through R2 and D2 to the Driver box input 1, enabling the FPD drivers
to move the Roman Pots.

3 -- Closing the drivers switch also enables software control for the
drivers movement, by the 1553 rack monitor interface -- 1553 RM -
digital output 1 connected through D1 to the driver box input 1. The
software control acts on the power box by the digital output 2 of the
1553 RM, going to the blower sense of the RMI. The reason for that is
that the blower sense controls the Fault Output in AND with smoke
detector, and also the Enable blower output, without interfering with
the FIRUS output as happens if the drip sense is used instead.

4 -- The smoke detector connected to the Rack Monitor Interface -- RMI,
disables the driver box and the power box if smoke is sensed, that sends
to ground the /Fault Output, that goes to the power box and the Enable
Blower output of the RMI, that goes to the second input of the driver
box. That means that all FPD electronics in the crate goes off, except
the 1553 RM, the RMI and the IIB. The FIRUS line is activated by the
smoke detector, going from high to low impedance.

There are two FIRUS lines, one for the proton side, connecting in daisy
chain the two RMI of P1 and P2 and the other for the antiproton side,
daisy chaining the RMI for A1, A2 and D. These two lines end in a 3 k
ohm resistor at P2 and A2 quadrupoles, that are sensed by the D0 FIRUS
system. The FIRUS lines come to rack PW08 in green RG58 coaxial cables
and there they are connected through a 4- wire shielded cable to the
FIRUS box in rack PN06. Both racks are in D0 platforms.

1\) To match the black cable to ribbon cable it is necessary to add in
parallel a 175 ohm resistor, 1/8 W or more, and to match the ribbon
cable to limo for plugging into NIM it is necessary to add in series a
20 ohm resistor, 1/8 W or more. The schematic is given in figure 1.

![](media/image3.wmf){width="5.977083333333334in" height="1.94375in"}

# Figure 1 -- FPD coaxial to flat cables impedance matching adapters

2)  A voltage divider is necessary for monitoring the +-10 and the +-15
    V from the amplifier low voltage power supplies. Four resistor
    voltage divider are needed for each of the voltages. For the +15V
    and --15V the two resistor voltage dividers are identical: 15V to a
    10 k ohm resistor with the other side to a 5 k ohm resistor that is
    connected in the other side to ground, and the resistors connection
    goes to a 1553 RM analog input. For the +10V and --10V the two
    resistors are equal, 10 k ohm each. That is, we translate all
    voltages to 5 volts, that is half of the 1553 RM full scale, 10 V.
    The +5V can sense directly by the 1553 RM analog input. 5 analog
    inputs of the 1553 RM will be used to sense the FPD rack low voltage
    power supplies voltages.

![](media/image4.wmf){width="5.907638888888889in"
height="3.2847222222222223in"}

# Figure 2-- FPD low voltage power supply monitoring voltage dividers 

**Map for AFE to flat ribbon cable interface ( 32 ribbon cables for each
AFE )**

![](media/image5.wmf){width="4.981944444444444in" height="8.4375in"}