Chapter 5 - Interlock System
5.1 General Layout of the Hardware Interlock System (Fig 5.1)
The hardware interlocks can be divided into two main systems. These are known as the motor control interlocks, described in Section 5.2 and the servo drive interlocks which are described in Section 5.4. The motor control interlock concern the operation of all ON/OFF switched motors which are controlled by motor boxes (MCB's). The main servo drive interlocks are only concerned with the servo motors and brakes for the primary movements of the telescope in its polar and declination axes.
Figure 5.1 shows the general layout and interconnection of all units in the hardware interlock systems. This drawing also shows the general cabling layout which is necessary for the transmission of interlock signals between the different units. The additional cabling which is used for the distribution of power supplies and control signals are not shown. The distribution of interlock signals within the cabling is listed in detail later. All MCB's which have external interlock connections are shown in the drawing together with their general locations. These units incorporate the motor control interlocks for the interlocking of all ON/OFF switches motors. The interlocks for the main servo drives are housed in the servo racks in the control room.
To simplify the distribution of interlock signals between different parts of the system to distribution boxes are used. These are labelled as DBXH and DBXF on Figure 5.1. All interlock signals which are transmitted troughout the system are identified by a standard form of coding. This code is explained in Section 5.2.3 and a complete list of all interlock signals and their codes is given in Section 5.5. The same codes are used in both the motor control interlocks and the main servo drive interlocks.
Interlocks are built into the telescope to ensure that the proper procedures are followed during the control of the telescope in particular during exchanges of the top unit and removal of certain parts of the telescope for maintenance purposes. In manual control is used then the correct procedures must be rigorously followed by the operator. If they are not then the operation of some of the telescope mechanisms will be automatically prevented by the hardware interlock systems. 360 Team develop a series of procedures in order to perform all the different maintenance and exchange works.
This section describes the safety interlocks which are incorporated in the motor control boxes for the ON/OFF telescope control motors (MCB switches). All motors of this type are concerned with the control and manipulation of different parts of the telescope. Each standard motor control box can control up to seven different motors.
To prevent any dangerous operations from taking place each motor control box constain a built-in hardware interlock system. Appropiate interlock signals are transmitted to each MCB from various part of the telescope. Using these signal a logical function is derived to govern the safe control of each motor. This logical function is a boolean expression which combines those interlock conditions which are relevant to the safe operation of a particular motor. When this expression is satisfied the motor is allowed to operate.
Section AA described the operation of the motor control circuitsand the function of the "B" relay this relay must be energized to allow the motor to operate. The logical function of each motor is realised in hardware using an individual interlock chain, consisting of a chain of relay contacts. Each contact represents one of the interlocks conditions which affects the motor. When the logical function of the motor is fulfilled an electrical path through the chain is completed. This energizes the "B" relay of the appropiate motor and allow it to operate.
As a standard Motor Control Box (MCB) can control up to seven different motor the interlock the interlock signals for all seven motors must be available in the MCB. These interlock signals are generally derived from the endswitch position of other motors. If these other motor are controlled by the same MCB the interlock signal is available locally. In other cases the interlock signal must be transmitted from other MCB's or interlock switches on various parts of the telescope.
5.2.2 Transmission of MCB Interlock Signals.
The most common type of interlock signal on the telescope is the endswitch position signals of the various motorized mechanisms. Each mechanisms that is controlled by an MCB switched motor as a pair of F1, F2 limit switches associated with it. They act locally in the motor control box (MCB) to cut power to the motor. Once the mechanisms has reached the end of its travel and the limit switch has been activated the motor can only be re-energized in the reverse direction. The end positions of these motorized mechanisms, as determined by their F1, F2 limit switches, in many cases a logical condition which is a part of the logical function of the other motors. In these cases the F1, F2 limit signals must be re-transmitted as general safety interlock conditions.
In several cases external interlock signals are required which indicate intermediate positions of a mechanisms, not the extremes of its travel. In these cases additional switches are fitted to the mechanism and are labelled F3,F4 as required. They are retransmitted from an MCB directly, without the use of relays.
Figure 5.2 is a schematic drawing of the standard control circuit for a single motor. The operation of this circuit, in particular the function of the F1, F2 relays, is explain in Section BB. These relays are normally energized unless the mechanisms reaches the appropriate limit switch. When a limit switch is reached the F1 or F2 relay de-energizes and cuts power to the motor. An additional contact on each F1, F2 relay is used to generate a 24 volt F1, F2 output signal. This signal is used for both the computer interface output and as a external interlock signal when required.
As their can be a total of seven motors controlled by one standard MCB their may be sevaral external interlock signals for transmission. It is sometimes possible to combine these signals logically before they are transmitted, in order to transmit a single output signal. This reduces the number of outgoing wires and simplifies the distribution of external interlocks. The wiring of combined interlock chains is described in Section 5.2.5. All external interlock signals to be transmitted, from F3, F4 switches, F1, F2 relays, and combined interlock chains, are wired via internal connectors to the Hirshmann 16 pole power socket. Five of the connections on this socket are used for the supply of 3 phase power to mcb. The remainder are available for the transmission and reception of external interlock signals.
The interlock signals are transmitted and received from each MCB over type H3 cable. Distribution of these signals between the MCB's on the telescope takes place trough two interlock distribution boxes, DBXH and DBXF, depending on the location of the particular MCB's, see Figure 5.1
5.2.3 Identification of Interlock Signals. (Refer to Section 5.5 for a list of interlock signals)
All Interlock signals are identified by a standard form of coding (old 360 coding). As most interlock signals are generated by the F1, F2 limit switches of the motors, the motor code itself is used. The code for the interlock signals becomes the motor code followed by the limit switch designation. For example H15F2 is the code for the F2 limit switch signal from motor H15. The codes for the motors themselves is derived from a letter code, indicating their location, followed by numbers indicating their grouping. When the interlock signal is generated by other independing position contacts or limit switches the same general form of coding is used.
In addition to their standard codes each interlock signal is given an abbreviated two symbol code. This allows a more compact description of the logical function of each motor. A complete list of all interlock signal and both types of code is given in Section BC. Refering to this list shows that the abbreviated code for interlock signal H15F2 is p1.
5.2.4 Principle of the MCB Interlock Circuit (Refer to Figure 5.3)
Figure 5.3 ilustrates the principle of the MCB interlock circuit. Each motor has an individual chain of interlock contacs wired to its "B" relay. These contacts are wired in such a way as to produce the logical function of the motor. When this function is fulfilled an electrical path through the chain is completed. The drawing shows a simple logical AND combination where all of the three contacts shown must be closed to energize the "B" relay. For more complicated functions an electrical path may be completed through the chain by various routes, whenever the logical function is satisfied.
All of the interlock signals ahich are to be used for the different motor functions are wired to interlock relay in each MCB. One interlock relay is used for each interlock signal. Volt-free contacts on these relay is used to wire the separate, individual interlock chain for each motor. Figure 5.3 shows how contacts from three interlocks relays are used to wire an interlock chains for one motor. There are twelve of these relays available in each standard MCB to accept a maximun input of twelve different interlock signals. Each relay has two volt-free contacts available which may thus be used in two different interlock chains if requiered.
To allow for visual checking and fault-finding an LED indicator is wired from each interlock relay. When an interlock signal is received the relay is energized and the LED illuminated as a visual confirmation of the signal.
5.2.5 The Interlock Panel. (Refer to Figure 5.4)
Each Standard motor control box incorporates a pictorial panel, or mimic diagram, which visually illustrates the logical function of each motor. Refer to Figure 5.4 which shows the interlock panel for MCBH1. Each of the seven motors controlled by the MCB is listed in a colum on the left hand side. Across the top of the panel a row of twelve LED indicators provide a visual signal for each of the interlock conditions.
Each relay contact which is used to build up a motor function is shown on the panel by a pair of adjacent small sockets. These sockets have a functional purpose described below. The interlock chain for each motor runs across the panel horizontally, from right to left, and is drawn to represent the motor function. The beginning of the chain, on the right, is the point at which a 24 volt supply enters each chain. The end of the chain, on the left, is the point to which each "B" relay is connected.
Many motors, such as H15, have a simple function which is wired with a series chain of a few contacts. Other motors have more complicated logical functions which are best described in boolean algebra, as summarized in the following section. However the interlock panel, togrther with the LED's gives an inmediate and graphical representation of each motor's logical function.
The interlock panel also has a functional purpose. Each pair of adjacent small sockets represents a relay contact, but in practice they are also wired in parallel with the actual relay contacts themselves. This allows a small jumper link to be manually inserted across any interlock contacts to bypass it. This facility is provided in case a fault develops in the wiring or source of an interlock signal. The insertion of these jumper links is a temporary measure, THEY SHOULD NOT BE INSERTED WITHOUT CARE OR FORETHOUGHT. Every interlock condition for each motor is provided for a genuine reason, they should only be bypassed temporarily if required during a fault.
COMBINED INTERLOCK SIGNALS.- F1, F2 limit switch signals are often transmitted out of an MCB as external interlock signals. When several signals are to be transmitted it is sometimes possible to combine them logically before they are transmitted. These signals are referred to as combined interlock signals. They are generated by using a logical chain to produce the required logical function in the same manner as that used for the motors. The combined interlock function is also displayed on the interlock panel of the MCB in which it is produced.
5.3 Ball Switch Sensors and Air Control Valves.
The ball switch sensors generate interlock signals which affect both of the main srvo-drive systems (polar and declination axes) and the air control valves for the main mirror. The sensors are housed in a control box, known as the ball switch case, which is mounted on the centre piece. This box contains three ball switches for measuring the elevation of the telescope tube with respect to the horizontal.
Each ballswitch consists of a cone which is aligned with the optical axes of the tube. The cone, which is filled with oil, contains a metal ball which is free to move between the two ends.
When the telescope tube moves through a particular angle the ball rolls from one end of the cone to the other. The position of the ball is sensed at each end using inductive sensors. These outputs are combined logically to generate a fail to safe output signal.
Three ballswitches are used to sense when the elevation of the telescope tube above the horizon is greater than 6º, 7º and 15º respectively. The 6º and 15º ballswitch signals are used in the main servo-drive interlocks. The 15º ballswitch signal is also wired into the servo system of both the polar and the declination axis drive. When the telescope tube is driven below an elevation of 15º the maximun permitted slewing rate of the telescope is automatically reduced. The tube then approaches the horizon at slow speed.
5.3.2 Main Mirror Air Control Valves
The main mirror is supported by a system of radial air pads. The presure in these air pads is automatically varied by a computer system as the mirror is tilted. This device controls the differential air pressures between the various mounting pads to maintain the mirror reflective surface at its correct position. Air clamps are also used to grip the mirror when required.
Both the radial pads and the air clamps may be switched on or off by solenoid air valves.. The 7º ballswitch signal is used in the control of both these valves. As the telescope tube approaches the horizontal the main mirror approaches its fully vertical position. At a tube elevation of 7º, corresponding to a mirror tilt of 83º, the air clamp are switched on and the radial air pads turned off. This allows the main mirror to be safely tilted trough its fully vertical position.
When the telescope tube is vertical the main mirror lies flat in its rest position. At this point the radial air pads may be switched off. The main mirror may then be removed if required for re-aluminizing or other maintenance work.
5.4 Main Servo Drive Interlocks
5.4.1 Introduction (refer to Figure 5.5)
Figure 5.5 shows the general layout of the LCU room equipment. The Rack D, contain all of the relays concerned with the Servo System for Alpha and Delta. The interlock system is completed in the unit labeled "Power Distribution" in alpha and delta racks (B and C). The power distribution unit also controls the electromagnetic brakes for polar and declination axes of the telescope. A pair of power amplifier in each rack (B and C) controls the servo motors for the telescope main drives. The only output function of the main servo drive interlocks is the switching of the power supplies to these servo drive system to allow them to operate. When the power is switched on, the electromagnetic brakes are automatically released.
Figure 5.6 shows a layout of the rack D rear panel and a view of the inner side. The Interlock system is located in the rear side of the rack. The inner panel is related with the manual control panel or Engineering panel.
The main function of the servo drive interlock is to control the power to the two power amplifier for each servo. Relays inside the power distribution chassis of each drive carry out this power switching. They are controlled by a logical combination of the various interlock signals: - polar axis interlock, declination axis interlocks and common interlocks. When all interlock have been made their is a time delay of 10 seconds before the power is applied to the servo motors.
5.4.2 Principle of the Interlock Chain. (Figure 5.7)
Figure 5.7 shows the overall scheme of the main servo drive interlocks. The drawing shows two interlock chains, the right hand side for the polar axis interlocks (alpha axis), and the left hand side for the declination axis interlocks (delta axis). A common section interlock are shown in the center.
A +24 Volts supply enters the interlock chain at the center top of the drawing. This power supply is wired through a chain of interlock contacts, for each axis. There are various bypass chains which are described in detail later. Each of this interlock contacts corresponds to one of the interlock conditions for each axis. When an interlock function is completed for one axis, the appropriate contacts through the chain are closed. This allow a +24 volts signal to pass through the chain to one end of the corresponding interlock relay coil shown at the bottom of the drawing.
The opposite ends of the interlock relay coils are wired through bridging links to ground. These links are made in the plug and socket connections to each power amplifier, PA1 and PA2 for each chain. The separate earth return for the interlock relay are only completed when the power cables are connected to the corresponding pair of the power amplifier, PA1 and PA2 for each chain.
5.4.3 Interlock Signals for the Polar Axis
O4, Hydrostatic Bearing Oil Pads.( ILALOILP-R ). Combined Interlock signal from the pressure and flow monitor in the oil supply lines to the polar hydrostatic bearings. Interlock signal O4 transmits when the oil pressure and flow to both pads is above the minimun required level.
n2, Polar Axis Lock ( ILALLOCO-R ). F1 limit switch signal from polar axis lock drive motor Q21. Interlock signal n2 (Q21F1) transmits when the lock pin is fully removed from the mating hole in the horse shoe.
Motor
Protection. (ILPAAL120A-R and ILPAAL220A-R ). Current sensing circuit breakers
in series with the power amplifier outputs to protect the polar axis servo motor
G11 and G12. The interlock signals transmit provided the appropriate circuit
breaker has not tripped due to excessive motor current.
Amplifier Protection. (ILPAAL1120-R and ILPAAL2120-R). Thermal sensors fitted
to the amplifier heat sinks to protect the main power amplifier 
PA1
and PA2. The interlock signals
transmit provided te temperature of the heat sinks is below 120ºC.
Limit East,
Limit West (ILLSALEAST-R and ILLSALWEST-R). F1, F2 limit switch signals from
bosh switches on the horse shoe drive. These switches are activated by cams
to define the maximun safe limits of travel in the polar axis. The interlock
signals transmit provided the horse shoe is within the limits of travel in EAST
and WEST directions. There are a further two limit switches, 
,
which are positioned just beyond the F1, F2 limits.
O2, Oil Lubrication. ( ILLSALWEST-R). Interlock signal from the oil pressure switch in the oil supply line to gear drives of the polar axis. Interlock signal O2 operates in an inverted manner because the sensor used has contacts of normally open type. This signal trnsmits when there is insufficient oil pressure in the supply to the gear drives.
5.4.4 Interlock Signals for the Declination Axis
O3, Hydrostatic Bearing Oil Pads. ( ILDEOILP-R ). Combined interlock signal from the pressure and flow monitors in the oil supply lines to the declination axis hydrostatic bearings. Interlock signals O3 transmits when the oil pressure and flow to every pad is above the minimun required level.
m2, Declination Axis Lock. ( ILDELOCO-R ). F1 limit switch signal from declination axis lock drive motor, M31. Interlock signal m2 (M31F1) is transmitted when the lock pin is fully removed from the mating hole in the telescope tube.
Motor
Protection ( ILPADE120A-R and ILPADE220-R). Same function as the polar axis
motor protection signals but in this case the signals are transmitted provided
the circuit breakers have not tripped for the declination axis servo motors,
G21 or G22.
Amplifier
Protection. ( ILPADE1120-R and ILPADE2120-R). Same function of the polar axis
amplifier protection signals but in this case they apply to the declination
axis, 
PA1 or PA2.
Limit North,
Limit South. ( ILLSDENORT-R and ILLSDESOUT-R). F1, F2 limit switch signals from
Bosh switches on the drive to the telescope tube. These switches are activated
by cams to define maximun safe limits of travel in declination axis. The interlock
signals are transmitted provided the telescope tube that tube is within the
limits of travel in North and South directions. There are a further two limit
switches 
which have the
same function as the
limits.
o1, Oil Lubrication (ILDELUBE-R). Same inverted function as the oil lubrication signal o2 but in this case the signal transmits when there is insufficient oil pressure in the supply to the declination axis gear drive.
5.4.5 Common Interlock Signals
r1, r2, r3, r4. Telescope emergency switches ( ILEMPRIM-R, ILEMCENT-R, ILEMCAGE-R and ILEMPLAT-R). These interlock signals come manually operated emergency switches situated at various points on the telescope. r1 - prime focus cage, r2 - centre piece, r3 - cassegrain cage, r4 - platform. There are an additional manually aperated emergency switch on the fron panel of the Engineering Panel an another in the third floor control room.
z1, Carriage Back (ILCARBAK-R). This combined interlock signal comes from platform control box, MCBP1. It is transmitted when all of the top units carriages are in their fully drawn back position.
h1, 15º Ball Switch ( ILBALL15-R). This interlock signal is generated by a ball switch in the ball switch case, CBR2. It is transmitted when the optical axis of the telescope tube is at an elevation of greater than 15º with respect to the horizontal.
h3, 6º Ball Switch ( ILBALL06-R). Same type of function as h1 but this signal is transmitted for an elevation of greater than 6º.
Sa2, Air Pressure Clamps (ILAIRCLA-R). This interlock signal comes from the ball switch case, CBR2. It is transmitted if the air pressure clamps for the main mirror are not applied.
East End,
West End, (these signals are generated by Bosh switches fitted to the horse
shoe drive (polar axis). They are activated by cams to define the absolute maximun
permissible travel of the horse shoe in each direction, East and West They are
positioned just beyond the normal limit switches .
If the horse shoe is permitted to travel as far as these F5, F6 switches then
power to the polar axis drives is permanently removed. This would only occur
during a failure of the equipment and the servo motors must be returned within
their limits using the manual handle.
j3, 
(ILLSDE-120-C)
This position signal is generated by a declination axis position contact (R21F3)
and is wired via a junction box, R2J1. It transmits when the elevation of the
telescope tube is higher than 1º below the horizontal.
k 
(ILAL12HR-C)
This position signal is generated by a polar axis position contact (R11F2) and
is wired via a junction box, R1J1. It transmit when the horse shoe is in its
12 O'clock position with the gap in the horse shoe facing vertically up-wards.
n1, Fully Locked
(ILALLOCI-R). F2 limit switch signal from polar axis lock drive motor, Q21.
Interlock signal n1 (Q21F2) is transmitted when the lock pin is fully engaged
in the mating hole in the horse shoe.
South End,
North End ( ILLSDESOUT-C , ILLSDENORT-C). Same function as the
signals but these interlocks signals define the absolute maximun permissible
travel of the telescope tube.
5.4.6 Operation of the Declination Axis Interlock Chain
Nearly all the interlock contacts open as a result
of a major fault in a part of the telescope the exception are m2, the declination
lock pin, and the two limit switches .
The limit switch contacts only open if the telescope tube is driven too far
in either direction. The declination lock contact, m2, does not indicate a fault
condition. This contact opens when ever the declination axis is locked, preventing
further movement of the telescope tube.
All of these local interlocks are wired in a simple chain. with the exception of m2, all their relay are connected so that a fault condition is memorized. This holds the appropriate contact in the interlock chain apen, until it is manually reset from the engineering panel pushbutton. When any of these local interlock contacts opens the declination axis interlock relay is de-energized. This interrupts the power supply to the declination axis servo drive until the interlock chain is manually reset.
Only for engineering purposes a series of bypass are ready to use as can see at the interlock circuit in Figure 5.8 labeled from P1 to P14.(This operation has to be made with extreme care and it is very important that at the end of the engineering session all bridges have to be removed.)
When the telescope is lowered to an elevation of 15º above the horizon the h1 contact opens (15º ball switch). At this point all of the top unit carriages must be in their fully drawn back position. It they are not then interlock contact z1 will be open and the interlock chain will be broken. This will de-energized the declination axis interlock relay and remove power from the servo drives. If the z1 contact is subsequently closed the interlock relay is re-energized automatically as z1 relay has no memory fuction connected. Power is reconnected to the declination axis after the 10 seconds delay in the power switching circuit.
When the telescope tube is lowered further to an elevation of 6º above the horizon the h3 contacts open (6º ball switch). The air pressure clamp must be on to bypass one of these h3 contacts with the clamp interlock signal Sa2. The other h3 contact may be bypassed by a series chain of three contacts, j3, k and n1. Contacts k and n1 ensure that the horse shoe is locked in its 12 O'clock position with the gap in the horse shoe facing vertically upwards. Contact j3 is closed at an elevation of 6º but opens at a negative elevation of 1º below the horizon, preventing the telescope the telescope tube from being driven any further down.
5.4.7 Operation of the Polar Axis Interlock Chain
The interlock contacts for the polar axis are connected
in a simple chain in the same manner as the declination axis interlocks. The
relay for the polar lock pin n2, and the two limit switches,
are not connected so that they memorize the signal. All the other polar axis
interlock signal are memorized.
Only for engineering purposes a series of bypass are ready to use as can see at the interlock circuit in Figure 5.8 labeled from P1 to P14.(This operation has to be made with extreme care and it is very important that at the end of the engineering session all bridges have to be removed.)
When the telescope is lowered to an elevation of 15º above the horizon the h1 contact opens (15º ball switch). At this point all of the top unit carriages must be in their fully drawn back position. It they are not interlock contact z1 will break the chain and cause loss of power to the horse shoe servo drives.
When the telescope tube is lowered further to an elevation of 6º above the horizon the h3 contacts open (6º ball switch). The top h3 contact open the bypass and breaks the interlock chain. This de-energizes the polar axis interlock relay and disconnects the power to the horse shoe servo drives. The second h3 contact has no apparent function. It is repeated in the same manner as the lower bypass branch of the declination axis servo chain.
The emergency switches are operated in the memorized mode.
5.4.8 Manual Override and End Switch Output Signals.
When power is removed from the servo drives of the polar or declination axis it may be possible to re energize them using the manual keyswitch. This is permitted if the appropriate interlock contact is bypassed. (Figure 5.8)
If either of the servo drive system has been de-energized by a limit switch, they may only be re-energized in the reverse direction. Output signals to the control servo chassis of the polar and declination axis specify in which direction the limit has been reached.
5.5 List of Interlock Signals and their Sources
5.5.1 List of Interlock Signals and their Sources
This list contains all of the interlock signals used on the telescope and also gives the "source" of each signal. This is the first control box, or control unit to which the interlock signal is wired. If the signal is only used in this unit and is not retransmitted, it is called a 'local' interlock signal. When the signal is retransmitted to additional control boxes it is called an external interlock signal.
Local interlock signal may in fact be some distance away from their control units, especially for those local interlock signals which are wired to the servo racks. These racks are delta rack (B), alpha rack (C) and interlock rack (D). (Figure 5.5)
After the upgrade in 1999-2000 a new names were added for same signal in order to be compatible with the VLT standards.
|
INTERLOCK SIGNAL
|
TYPE
|
SOURCE
|
FUNCTION
|
|
|
a1
|
P41F1
|
EXTERNAL
|
MCBP4
|
Carriage 1 Competely Back |
|
a2
|
P51F1
|
EXTERNAL
|
MCBP5
|
Carriage 2 Competely Back |
|
a3
|
P21F1
|
EXTERNAL
|
MCBP2
|
Carriage 3 Competely Back |
|
a4
|
P31F1
|
EXTERNAL
|
MCBP3
|
Carriage 4 Competely Back |
|
z1
|
(a1 . a2 . a3 . a4)
|
COMBINED
|
MCBP1
|
All Carriages completely Back. |
|
a5
|
OFF line P2
|
LOCAL
|
MCBP2
|
Carriage 3 on Manual |
|
a6
|
OFF line P3
|
LOCAL
|
MCBP3
|
Carriage 4 on Manual |
|
a7
|
OFF line P4
|
LOCAL
|
MCBP4
|
Carriage 1 on Manual |
|
a8
|
OFF line P5
|
LOCAL
|
MCBP5
|
Carriage 2 on Manual |
|
b1
|
P15F3
|
LOCAL
|
MCBP1
|
Carriage 3 on Loading Position |
|
b2
|
P15F4
|
LOCAL
|
MCBP1
|
Carriage 4 on Loading Position |
|
b3
|
P15F5
|
LOCAL
|
MCBP1
|
Carriage 1 on Loading Position |
|
b4
|
P15F6
|
LOCAL
|
MCBP1
|
Carriage 2 on Loading Position |
|
INTERLOCK SIGNAL
|
TYPE
|
SOURCE
|
FUNCTION
|
|
|
b5
|
P22F1, P22F2
|
LOCAL
|
MCBP2
|
Carriage 3 Fast Drive Sector |
|
b6
|
P32F1, P32F2
|
LOCAL
|
MCBP3
|
Carriage 4 Fast Drive Sector |
|
b7
|
P42F1, P42F2
|
LOCAL
|
MCBP4
|
Carriage 1 Fast Drive Sector |
|
b8
|
P52F1, P52F2
|
LOCAL
|
MCBP5
|
Carriage 2 Fast Drive Sector |
|
c1
|
H51F1
|
EXTERNAL
|
MCBH2
|
No Tube West Misalignment |
|
c2
|
H51F2
|
EXTERNAL
|
MCBH2
|
No Tube Eest Misalignment |
|
c3
|
H51F3
|
EXTERNAL
|
MCBH2
|
No Tube Botton Misalignment |
|
c4
|
(c1 . c2)
|
COMBINED
|
MCBP1
|
No Tube Upper Misalignment |
|
d1
|
H51F1
|
EXTERNAL
|
MCBH2
|
Top Unit Fully In |
|
d2
|
--
|
COMBINED
|
MCBH3
|
Top Ring Locked |
|
d3
|
H41F3 to H44F3
|
LOCAL
|
MCBH3
|
Top Ring In |
|
e1
|
P23F3
|
LOCAL
|
MCBP2
|
Carriage 3 Forks In |
|
e2
|
P33F3
|
LOCAL
|
MCBP3
|
Carriage 4 Forks In |
|
e3
|
P43F3
|
LOCAL
|
MCBP4
|
Carriage 1 Forks In |
|
e5
|
P23F4
|
LOCAL
|
MCBP2
|
Carriage 3 Empty |
|
e6
|
P33F4
|
LOCAL
|
MCBP3
|
Carriage 4 Empty |
|
e7
|
P43F4
|
LOCAL
|
MCBP4
|
Carriage 1 Empty |
|
INTERLOCK SIGNAL
|
TYPE
|
SOURCE
|
FUNCTION
|
|
|
f1
|
U45F2
|
EXTERNAL
|
MCBU4
|
Coude Locked to Tube |
|
f2
|
U35F2
|
EXTERNAL
|
MCBU3
|
Cassegrain locked to tube |
|
f3
|
U11F2
|
EXTERNAL
|
MCBU1
|
Prime Focus Locked to Tube |
|
f5
|
P23F2
|
EXTERNAL
|
MCBP2
|
Unit Locked to Carriage 3 |
|
f6
|
P33F2
|
EXTERNAL
|
MCBP3
|
Unit Locked to Carriage 4 |
|
f7
|
P43F2
|
EXTERNAL
|
MCBP4
|
Unit Locked to Carriage 1 |
|
g1
|
U47F2
|
LOCAL
|
MCBU4
|
Coude Mirror Cover Closed |
|
g2
|
U37F2
|
LOCAL
|
MCBU3
|
Cassegrain Mirror Cover Closed |
|
h1
|
R22F1
|
EXTERNAL
|
CBR2
|
Tube Above 15º |
|
h2
|
R22F2
|
EXTERNAL
|
CBR2
|
Tube Above 7º |
|
h3
|
R22F3
|
EXTERNAL
|
CBR2
|
Tube Above 6º |
|
j1
|
R21F3
|
EXTERNAL
|
SERVOS
|
Tube Vertical |
|
j2
|
R21F4
|
EXTERNAL
|
SERVOS
|
Tube Horizontal |
|
j3
|
R21F7
|
LOCAL
|
SERVOS
|
Tube Above Horizon |
|
j4
|
R21F5
|
LOCAL
|
SERVOS
|
Tube Above Pole |
|
F1(
) |
R21F1
|
LOCAL
|
SERVOS
|
Tube Limit South |
|
F2(
) |
R21F2
|
LOCAL
|
SERVOS
|
Tube Limit North |
|
F6(
) |
R21F6
|
LOCAL
|
SERVOS
|
Tube at Equator |
|
F8(
) |
R21F8
|
LOCAL
|
SERVOS
|
Tube End Stop South |
|
F9(
) |
R21F9
|
LOCAL
|
SERVOS
|
Tube End Stop North |
|
INTERLOCK SIGNAL
|
TYPE
|
SOURCE
|
FUNCTION
|
|
|
k
|
R11F4
|
EXTERNAL
|
SERVOS
|
Horse Shoe at 12 O'Clock |
|
F1(
) |
R11F1
|
LOCAL
|
SERVOS
|
Horse Shoe Limit East |
|
F2(
) |
R11F2
|
LOCAL
|
SERVOS
|
Horse Shoe Limit West |
|
F3(
) |
R11F3
|
LOCAL
|
SERVOS
|
Horse Shoe Init Alpha |
|
F5(
) |
R11F5
|
LOCAL
|
SERVOS
|
Horse Shoe End Stop East |
|
F6(
) |
R11F6
|
LOCAL
|
SERVOS
|
Horse Shoe End Stop West |
|
m1
|
M31F2
|
EXTERNAL
|
MCBM1
|
Telescope Tube Lock In |
|
m2
|
M31F1
|
EXTERNAL
|
MCBM1
|
Telescope Tube Lock Out |
|
m3
|
M31F3
|
LOCAL
|
MCBM1
|
Tube Balanced + |
|
m4
|
M31F4
|
LOCAL
|
MCBM1
|
Tube Balanced - |
|
n1
|
Q21F2
|
EXTERNAL
|
MCBF1
|
Horse Shoe Lock In |
|
n2
|
Q21F1
|
EXTERNAL
|
MCBF1
|
Horse Shoe Lock Out |
|
n3
|
Q21F3
|
LOCAL
|
MCBF1
|
Horse Shoe Balanced + |
|
n4
|
Q21F4
|
LOCAL
|
MCBF1
|
Horse Tube Balanced - |
|
o1
|
G23F1
|
LOCAL
|
HYDRAULIC*
|
Delta Oil Lubrication |
|
o2
|
G13F1
|
LOCAL
|
HYDRAULIC*
|
Alpha Oil Lubrication |
|
o3
|
--
|
EXTERNAL
|
HYDRAULIC*
|
Delta Hydrostatic Bearing |
|
o4
|
--
|
EXTERNAL
|
HYDRAULIC*
|
Alpha Hydrostatic Bearing |
|
p1
|
H15F2
|
EXTERNAL
|
MCBH1
|
M3 Arm Lock to Hubsection |
|
p2
|
H11F2
|
LOCAL
|
MCBH1
|
M3 Arm In |
|
p3
|
H11F3
|
LOCAL
|
MCBH1
|
M3 Arm on Fast Sector |
|
p4
|
H11F1
|
LOCAL
|
MCBH1
|
M3 Arm Out on Hubsection. |
|
INTERLOCK SIGNAL
|
TYPE
|
SOURCE
|
FUNCTION
|
|
|
q1
|
H13F2
|
LOCAL
|
MCBH1
|
M3 Locked to Arm (Lower) |
|
q2
|
C21F2
|
LOCAL
|
MCBH1
|
M3 Hook Locked to Sky Baffle |
|
q3
|
C14F2, C15F2
|
EXTERNAL
|
MCBC1
|
M3 Cover Closed |
|
q4
|
C23F1
|
EXTERNAL
|
MCBC1
|
M3 Power Plug Out. |
|
q5
|
C24F2
|
EXTERNAL
|
MCBH1
|
M3 Twin Locked to Sky Baffle |
|
q6
|
H14F1
|
LOCAL
|
MCBH1
|
M3 Unlocked to Arm (Upper) |
|
q7
|
C21F3
|
LOCAL
|
MCBH1
|
M3 Mechanic Locked to Sky Baffle |
|
r1
|
EMERGENCY SWITCH
|
LOCAL
|
SERVOS
|
Prime Focus Cage Emergency |
|
r2
|
EMERGENCY SWITCH
|
LOCAL
|
SERVOS
|
Center Section Emergency |
|
r3
|
EMERGENCY SWITCH
|
LOCAL
|
SERVOS
|
Cassegrain Cage Emergency |
|
r4
|
EMERGENCY SWITCH
|
LOCAL
|
SERVOS
|
Platform Emergency |
|
z1
|
(a1 . a2 . a3 . a4)
|
COMBINED
|
MCBP1
|
|
|
z2
|
(j2 . k . n1 . m1)
|
COMBINED
|
MCBF1
|
|
|
z3
|
(z2 . c1 . c2 . c3)
|
COMBINED
|
MCBP1
|
|
|
z4
|
(k . n1)
|
COMBINED
|
MCBF1
|
|
|
t1
|
Q31F2
|
These interlock signal are intended to replace m1, m2, m3, m4 | ||
|
t2
|
Q31F1
|
|||
|
t3
|
Q31F3
|
|||
|
t4
|
Q31F4
|
|||
|
Sa1
|
--
|
LOCAL
|
SERVOS
|
Main Mirror Air Support |
|
Sa2
|
--
|
LOCAL
|
SERVOS
|
Main Mirror Air Clamps |
|
Val
|
--
|
LOCAL
|
CBR2
|
|
(Note *.- Hydraulic- These signals are wired in the BBC Hydraulic Plant at 360 Telescope third floor)
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