Barrel Electronics

The barrel electronics section of this manual contains descriptions of the barrel electronics for the DEIMOS Spectrograph. It corresponds to the Barrel Electronics tab in the electronics schematics binder.

Sheet 1:

Simplified Drawing

Photos

 

Galil panel #1	Galil panel #1 and Lamp interlock box	Galil panel #2	Galil panel #2 and Ion Pump controllers
Controller #1 Front	Controller #1 Top	Controller #2 Front	Controller #2 Top

 

Lantronix, A2S convertor, Data Logger, and SCSI-to-Fiber convertor	Orange circuit over temperature control and HP data logger sensor junction box	Lantronix Time-on Relay and Slitmask Barcode Supply
Bay 3 front view	Bay 3 rear view	Bay 3 top view

 

Lantronix Terminal Server: (see Bay 3 photo)

This sheet shows all of the components of the electronics mounted in the electronics ring except the CCD controllers. At the top of the drawing are the communication lines of the instrument. The block in the top left represents the Lantronix ETS8P terminal server. The terminal server supplies 8 serial port using RJ-45 connectors. The ports are allocated as follows:

1. Test port - left open for direct connection to the Lantronix for configuration.
2. Slitmask bar code scanner.
3. <Not assigned>
4. <Not assigned>
5. Galil controller #1
6. Galil controller #2
7. Piezo controller. (Tent Mirror control)
8. HP Data Logger. (Temperature logging)

A race condition can exist when power is applied to the instrument. The Lantronix box can become confused if it receives 'garbage' characters on it's serial ports while it is powering up. To insure that the Lantronix power is the last box to come on, a Potter & Brumfield 1.8 to 180 second 'Time-On' delay relay is wired in series with the AC power for the box. The relay and socket are located on the back of the Lantronix mounting plate and the delay is set to about 60 seconds.

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Bar Code Scanner:

Slitmask Barcode Reader

To the right of the Lantronix box are boxes that represent the bar code reader, the data logger, and the piezo controller. The Symbol Technologies LS 1220 bar code reader for the slitmask system is mounted inside the instrument on a solid mount that allows it to scan the bar-codes affixed to the individual slitmasks. This unit is powered by an AC wall adapter that is located at the back of the rack containing the Lantronix box. The adapter is held in place with a with metal strap. Though the power is always on, the beam is turned off and on via software and currently is planned only to be on when the slitmasks are initially inserted into the cassette. The scanner is a serial device and is connected to Lantronix port 2.

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HP Data Logger: (see Bay 3 photo)

Extra info:

HP Data logger

Beneath the barcode scanner is the HP Model 34970A Data Logger. This box can control as many as 30 RTD type sensors (R.T.D. Company, RS2P-463). The DEIMOS instrument has 27 sensors wired in. The data is read once every ten minutes and archived on the data taking computer. The idea is to keep record of the temperatures at various points on the structure that can be examined to see how the instrument acclimates to the mountain top and also as a record in case of any unexpected behavior of the instrument. At this time, there are no plans to display the inputs but a process can be set up to dump the data to a window if necessary.

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The Physik Instrumente P-845 Piezo Controller:

Piezo Controller

The Piezo control box is again a serial device and it communicates via Lantronix port 7. It controls the position of the tent mirror which is part of the flexure compensation system. The tent mirror can steer the light beam to keep the image on the detector steady as the instrument rotates and flexes. The actuator is a self contained unit that consists of a piezo element and a strain gauge. It has a stroke of 90 microns and can be controlled either via the communications port or front panel controls. The unit must always be set for remote operation. The operation manual and user guide accompany the outside vendor manuals bundle.

Front panel switch settings
PDF version of Operating Manual

Please note: the controller box MUST be powered down before connecting or disconnecting the actuator.

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Galil Controller #1:

Extra info:

Simplified Drawing - Click on boxes for detailed description

To bring up the detailed description of any stage click on it's box in the above diagram.

The above drawing illustrates the stages controlled by Galil controller number 1. The yellow block at the top, center of the diagram represents the Galil DMC-1580-72 Servo Motor Controller. The part number indicates that the unit is a 1500 series, 8-axis controller with an additional 72-bit I/O expansion box. To the right of the controller block are the three I/O racks and below it are two Galil AMP-1140 servo amplifiers. Below the controller are the two AMP-1140 servo amplifiers.
The controller connects via three 50-pin ribbon cables directly to the Expansion I/O. The expansion I/O consists of three banks of 24 bits. The first 24 bits can be programmed to be either outputs or inputs. The other two banks are dedicated as inputs. For our implementation, the first 24 bits are programmed as outputs. This is done by setting the Galil variable CO to 7. Each bank of 24 bits leave the Galil controller via a 50-pin ribbon cable. Galil has configured the I/O pin assignments to match the Opto-22™ G4PB24 I/O rack. We have used these components to simplify wiring of the instrument.

Below the yellow block are the two pink blocks that represent the two Amp-1140's. Each amplifier can independently power up to four servo motors. In the case of amplifier #1A, only two stages are connected: the TV Filter stage at J1 and the TV Focus stage at J2. These stages are mounted in the front of the instrument with the Photronics PXL camera. The filter wheel has eight positions and is normally loaded with 7 filters and an open position. The TV Focus stage motorizes the focus ring on the Kodak 200 mm lens.

The Filterwheel Stage is an unconstrained stage, meaning that it does not have forward or reverse limits. The stage is set by finding the fiducial to set the zero point. The Focus Stage is a standard, constrained stage. It again uses a fiducial for setting the zero point but also has three types of end of travel limits: first is the software limit, then the primary hardware limit, and lastly, the secondary hardware. The software should keep the stage from traveling past the software limit. If it fails to stop the stage, the primary hardware limit sends a limit tripped signal to the controller which should stop the motor. Once the primary limit is violated the controller should only allow the stage to move away from the limit. If both the software and primary limits fail, the secondary limit interrupts the power to the motor. At this point, the stage must be driven out of the limit by physically turning the motor shaft. See the TV Filter and Focus pages for more info on these stages.

Amplifier 1B controls the CCD dewar focus and translation stages along with the science filterwheel. Control of the two CCD stages is unique in the instrument. Due to the small motion of these stages, the limit switches that had to be used do not come in a 2PDT. Thus, the secondary limits do not generate a input for the Galil controller. The stages both have the usual software limits that should keep the stage from reaching the hardware limits. They also have the primary hardware limit that tells the Galil controller to stop motion (only) in that direction. The secondary limits, however, are SPDT switches that are wired in series with the motor current. The difference with these stages is that the controller does not receive the feedback that it would get from a normal secondary limit. This is not critical in that the stages would have to be backed out of the limit manually anyway.

The final stage on controller #1 is the Science Filterwheel Stage. It is an unconstrained stage, meaning that it does not have forward or reverse limits. The stage is set by finding the fiducial to set the zero point. The filters are centered in the beam by moving a predetermined number of encoder counts.

Galil Controller #2:

Extra info:

Simplified Drawing

The above drawing illustrates the stages controlled by Galil controller number 2. The yellow block at the top, center of the diagram represents the Galil DMC-1580-72 Servo Motor Controller. The part number indicates that the unit is a 1500 series, 8-axis controller with an additional 72-bit I/O expansion box. To the right of the controller block are the three I/O racks and below it are two Galil AMP-1140 servo amplifiers. Below the controller are the two AMP-1140 servo amplifiers.
The controller connects via three 50-pin ribbon cables directly to the Expansion I/O. The expansion I/O consists of three banks of 24 bits. The first 24 bits can be programmed to be either outputs or inputs. The other two banks are dedicated as inputs. For our implementation, the first 24 bits are programmed as outputs. This is done by setting the Galil variable CO to 7. Each bank of 24 bits leave the Galil controller via a 50-pin ribbon cable. Galil has configured the I/O pin assignments to match the Opto-22™ G4PB24 I/O rack. We have used these components to simplify wiring of the instrument.

Below the yellow block are the two pink blocks that represent the two Amp-1140's. Each amplifier can independently power up to four servo motors. Amplifier #2A has the following stages connected: J12 and J32 are connected to Grating Tilt mechanism #3, J13 and J33 connect to Grating Tilt mechanism #4, and J14 connects to the grating select stage. Connectors J32 and J33 connect to each stage's auxiliary encoder (Gurley Precision model 8335-11250-CBSA). The secondary encoders are used to position the stage while the primary encoders are used to close the servo loop. These stages are wired as normal constrained stages with the addition of the auxiliary encoders. Again, the constrained stage has software, hardware primary, and hardware secondary limits. The software limit should stop the tilting motion of the grating when encountered, the primary limit connects to the Galil controller limits that should stop any additional motion in the direction of the limit, and the secondary limit removes power to the motor in case both other limits fail.

Grating Tilter #3	Grating Tilter #4

The Grating Select stage is a normal constrained stage as above. This stage moves the select grating tilt mechanism into the light path at the grating box. Once there, a set of 5 pneumatic clamps lock the grating into place. In addition to the normal stage limits and home fiducial, the grating select stage uses an extra optical-slotted switch (PRM) to define the position of the selected grating. Under software control, the select mechanism moves the grating tilt mechanism into rough position for clamping. Once there, the PRM is activated and the select stage does a homing routine to the edge of a blocking flag attached to the grating cell. Once that is done the clamps are activated in a sequence that helps make the final clamping position as accurate as possible.

Grating Select Stage

Amplifier #2B controls only the Slitmask stage via J15. The Slitmask stage is really a combination of a constrained motor stage and a highly specialize pneumatic stage. The servo motor runs what amounts to a scissors jack that positions the slitmask cassette to discrete positions for each of the slitmask slots. Again, the constrained stage has software, hardware primary, and hardware secondary limits; the software limit should stop the scissoring motion of the stage when encountered, the primary limit connects to the Galil controller limits that should stop any additional motion in the direction of the limit, and the secondary limit removes power to the motor in case both other limits fail.

Slitmask Scissors Stage

Sheet 2:

Simplified Drawing

Galil Controller #1 Expansion I/O:

The above drawing shows the connections and cabling for the expansion I/O for Galil Controller #1. Note that the first I/O block is set for outputs and that blocks 2 and 3 are inputs. The pinouts for the Galil cables are :

1. Fiber-to-SCSI convertor
2. AIA-to-SCSI convertor
3. Camera controller

Connector J50 is wired to the EL-3003 AC power controller. This connection allow the Galil controller software shut down the orange circuit power if the temperature become too hot. The controller's signal is wired in parallel with a 85° F thermostat that will force the AC power off if for some reason the Galil becomes disabled. A quick note: if the thermostat has a lot of histerysis, if it does trip off the AC, the thermostat will have to cool down before it will let the power be reapplied.
Connector J52 is the main control cable for the calibration lamp system. It contains the AC lines that are used to apply power to the various lamp power supplies.
Connector J58 is the cable for the Filter Wheel pushbutton Station. The pushbutton station provides local control at the filterwheel for use when loading/unloading filters.
Connector J53 connects to the hatches that give access to the inside of the barrel. These are the Man Hatch, Dewar Hatch #1, and Dewar Hatch #2. The wiring allows the control computer identify which hatch is causing the instrument to not rotate.
Connector J51 is wired to the Potheus Flow meter. The Photometrics TV system is powered only when the coolant is flowing.

Simplified Drawing

Galil Controller #2 Expansion I/O:

The above drawing shows the connections and cabling for the expansion I/O for Galil Controller #1. Note that the first I/O block is set for outputs and that blocks 2 and 3 are inputs. The pinouts for the Galil cables are :

Sheet 3:

This sheet is a graphical representation of the barrel electronics ring.

Troubleshooting:
The controller also connects to the servo amplifiers via four flat ribbon cables each. These carry the signals between the controller and the amplifiers. The cables carry the motor control and enable signals plus limit switch and miscellaneous signals. To aid in troubleshooting, we have added extra ribbon cable connectors to the cables that allow a technician to probe the individual signal lines with a meter or oscilloscope.

The following table contains links to pinouts for the ribbon cables that connect the DMC-1580 controller to the Amp-1140 amplifiers. The Jn and JDn cables do not always carry the same signal on the same pins. The is mostly, but not exclusively, true on J5 and JD5, the I/O cable. The last three cables, the Galil I/O cables J1 - J3, are the cables that connect from the Galil 72-bit I/O board to the Opto-22 relay racks.

Galil controller interconnect cable pinouts

Galil Cable J2 Pinout		Galil Cable JD2 Pinout
Galil Cable J3 Pinout		Galil Cable JD3 Pinout
Galil Cable J4 Pinout		Galil Cable JD4 Pinout
Galil Cable J5 Pinout		Galil Cable JD5 Pinout
Galil I/O Cable J101
Galil I/O Cable J102
Galil I/O Cable J103