1. The Original LittleDog
The spex instrument controller is called littledog.
It is use to control and monitor stepper motors, temperature sensor,
serial devices (animatic motors), ac power (lamps), and other analog and
digital IO.
Spex littledog requirements:
6 stepper motors:
1) Calmir slide , Stepper linear slit with Neg and Pos TTL limits. (need to ckeck).
2) Dichoric Wh, Stepper motor with Detent and Home TTL (via HE) and HE voltage to PC.
3) OS flt Wh , Stepper motor with Detent and Home TTL (via HE) and HE voltage to PC.
4) Slit Wh, Stepper motor with Detent and Home TTL (via HE) and HE voltage to PC.
5) Guider Flt Wh, Stepper motor with Detent and Home TTL (via HE) and HE voltage to PC.
6) Array focus slide, Neg and Pos TTL (via HE) and HE voltage to PC.
NOTE: All stepper have 6400 steps/rotation, except for AFOC which has 28000..40000(?) steps/rotation.
2 serial motor: rotator, slit
1) Rotator, Anamatics SM 3410-V76 with Home TTL (via HE), and HE voltage to PC.
2) Grating Turret, Anamatics SM 3410-V76 with Home TTL (via HE), and HE voltage to PC.
3 serial temperature controllers
4 AC power for lamps (using modifed RPC controlled using PC's parallel port).
7 analog inputs: Hall-Effect voltage monitor by PC. Devices are:
dichroic, OSflt, Rotator, Slit, Grading, GuideFlt, ArrayFoc.
Grating_Init requires the HE data for homing.
Rotator_Init requires the HE data for homing.
Array Focus requires the HE data as its position sensor.
littledog is a 486 SBC and passive backplane. It peripherals device are:
ICS ADIO 1600 IO ISA card (no replacement or spares available)
Cyclades Cyclom-8 ISA multiport serial port board w/ 8 serial devices.
(no replacement or spare available).
PC58-8 8 axis controller, ISA board.
(A PC-48 ISA board still commerically avaiable)
(A PC-78 PC-104/Serial w/ 4 axis is commerically available)
A modified RPC3 AC control unit used to AC power to 4 lamps. This unit
is controlled using the PC parallel port.
LittleDog run linux, and has C programs to control and monitoring these device.
Bigdog and Guidedog use Remote Procedure Calls to littledog to run the motor
control applications.
2. LittleDog Options for Spex2.
Having a deicated PC for littledog was convienent as it separated motor control
from the bigdog/guidedog controllers (rebooted more often). Any reboot did not
require lengthy motor initialization.
Design Goals for spex2:
1. try to use serial/ethernet based controller (avoid peripherial boards).
2. Keep the PC generic, and not require it to be located at cass.
3. Use solutions that can be applied to icshell or other IRTF projects.
Embedded PC options: EE Box PC, or Mini-ITX motherboard (if PCI slot needed).
- Small, low power, and cheap.
Serial Device Option:
- DigiPort (Or IP serial, or if embedded PC not desired), $800
- PCI multiport board (with native linux support).
ie: Moxa C168H/PCI, $200-$500(?)
- USB multiport board (with native linux support).
ie: Edgeport/8, USB to serial, $500, vendor drivers required.
Stepper Motor Controller options: $3000
- GalilMC DMC-21x3 - 8 axis stepper motor controller, ethernet or serial.
Analog and digital IO can be included.
(make sense if icshell will use this).
- PC-48 (ISA board) or PC-78 (serial interface) are compatible with the
current PC58 in software.
IO Controllers options: - provide analog and digital IO over ethernet.
- GalilMC RIO-47xxx - Compact ethernet IO unit. $400/ea
- OPTO22 - Used by TCS3. $1000
3. Possible Configurations
3.1 Spex GalilMC controller.
Digi Port $2K ( 2 smart motor + 3 temper controller + ?)
GalilMC Controller setup $3K (ethernet motor controller /w analog and digital IO).
Spares $4K
Drivers/Power supplies $3K
New motors (6*500) $3K (but could reuse old ones).
* Reuse all stepper motors.
* New type of motor controller = software/engineering work.
* might be used by ishell
* step resolution/position don't change.
3.2 Spex with Animatics SmartMotors
10 Smart motors @1K each: $10K (6 stepper to be replaced, 2 smart motor, 2 spares)
Digi Port $2 (8 smart motor + 3 temperature controllers/monitors + ?)
IP based AIO and DIO $2 (7 analog input; 4 digital out for lamps).
1 ethernet stepper motor $2K (afoc reuses motor, new controller/drivers).
(unless we can change llive with 5x lower resolutions).
* less hardware
* step resolution/position changes (can use 8000 steps/rev model).
5x less for afoc.
4. Recommendation.
Spex should keep its current configuation of 6 stepper, and 2 animantics motor. The
computer and controllers require upgrading. A work summary/cost estimate is provide below:
Description cost
--------------------------------------------------------------- -------
1. Update the Hall-Effect Preamp/comparator board? $1K
2. Temperature contoller? reuse the old unit form spex. (TBD) ---
3. EtherIO unit (opto22 with analog IO and relay modules) $2K
4. 8 axis Stepper motor controller from Galil $4k
Plus motor drivers
5. Digi Port $1K
6. little Dog Computer $1K
7. 2 or 3 19" electronic boxes /w connectors, cable power, etc $4K
8. software effort
9. spares $2K.
---------------------------------------------------------------------------
$15K
Estimate Man-Power:
EE: 1 month
ET: 2 month
Software: 4 months
Not included:
GPS solution, $2K
Schedule:
The control system can be built and tested in the lab prior to spex being removed from the
telescope. TD, DW, EW can work on these items slowly begining immediately to when spex is
offline. When spex is in the lab, Tuning the code and sensor will need to be done on the
warm and cold dewar, but this code be done at a rate of 1 or 2 mechanism per week.
(8 mechanism / 2 = 4 weeks).