Motor Commands

There are essentially four commands for controlling motors. Two of those commands work with keywords and two of them work directly with the Animatics motor controllers command language. The following is a synopsis of the commands which are discussed in detail below.

mm camraw=20000 mm writes to keywords sm camraw sm reads keywords tm 1 AMPS=75 tm writes Animatics commands am 1 RAMPS am reads a single Amimatics status value

Analogous Lakeshore and DGH commands
Reading/Writing Keywords The commands affecting keywords are the observatory wide standard commands which allow one to read and write keyword values. The write command is 'modify' and the read command is 'show'.
The use of show and modify requires one to specify a 'service'. In the case of NIRC2, example commands would be :

modify -s nirc2 camraw=2000 show -s nirc2 camraw

Unix aliases have been created for show and modify as shortcuts, so the examples can be simplified to:
mm camraw=2000 sm camraw
Note that 'mm' and 'sm' are acronyms for 'modify mechanism/motor' and 'show mechanism/motor'.
For trouble shooting tips, click here.
To see how to run these commands in a script, click here.
The list of mechanism keywords is quite extensive. One can visualize the keywords, in most cases, as a composite of a mechanism prefix and a command suffix. A complete discussion of the mechanism keywords can be found in the design book. However, a quick synopsis is that for each mechanism the following command suffices exist:
INIT setups of motor control params; must be done after power cycling and/or resetting a motor; when read, returns true if init has been completed and false otherwise HOME causes a motor to perform its homing procedure; when read, returns true if homing has been completed RAW mechanism's position in encoder counts DELTA offsets a mechanism in encoder counts; write only BRAKES sets/releases brakes; write only ENABLE enables/disables motor power (servo); write only MTR mechanism's associated motor number INFO returns a list of all discrete positions and names associated with those positions for a mechanism SIM controls mechanism simulation RESET causes a motor controller to reset; init is necessary afterwards STOP decelerates a moving motor; note that the backlash removal will still occur so multiple stops are often necessary KILL instantly stops a moving motor; suffers from the same backlash removal problem as stop NUM mechanism's position as an ordinal numbers; returns -1 if the encoder value does not correspond with a known position NAME mechanism's position by name where a name is associated with a specific ordinal position; if the encoder value does not correspond with a known ordinal position then the mechanism's name keyword is set to 'unknown' DIST/ANGL mechanism's position in engineering units, typically in millimeters (sliders) or degrees (wheels) IDLE indicates whether or not a mechanism is idle/not moving; read only RDY ready status; idle and at the last demanded position; read only STAT current state (idle, moving, ...); read only TARG/TRGT current destination as a named position; is set to 'undefined' if the encoder value does no correspond to an ordinal position; read only DEST current destination in encoder counts; read only LMTORIDE allows one to override a mechanism's travel limits MAXPE sets a mechanism's maximum allowed postion error MAXPOS negative software travel limit; read only MINPOS positiive software travel limit; read only) ACCEL allows setting motor acceleration; write only AMPS allows setting motor current; write only BLASH allows setting backlash correction in encoder counts; write only VEL allows setting maximum motor velocity; write only

Reading/Writing Motor Controller Parameters
The commands for interfacing to the Animatics motor controllers are 'askmotor' and 'tellmotor'. The aliases for these are, respectively, 'am' and 'tm'.
The difference between askmotor and tellmotor is that askmotor waits for a motor response and, hence, would be used for reading current motor controller values (eg. RP, RA, Rg, Rh, RAMPS, ...).
To use these commands one must specify a motor number followed by a string comprising of an Animatics command. One can specify multiple Animatics commands if they are all enclosed in a single set of double quotes. Be aware that askmotor will only wait for a single response, so a string consisting of multiple commands should only contain a single query command. Also be aware that command strings are not parsed/inspected but are sent exactly as typed, hence, case is important.
am 1 RP returns motor 1's current position am 2 RE returns motor 2's max allowed position error am 2 Re returns motor 2's variable 'e' value am 3 "AMPS=50 RA" sets motor 3's max current and returns it's current max acceleration value tm 4 "g=1 RUN" causes motor 4 to execute it's init subroutine tm 4 "g=4 RUN" causes motor 4 to execute it's homing subroutine tm 4 "d=2000 g=2 RUN" this sequence would set motor 4's destination to 2000 and cause it to execute its move subroutine tm 5 V=128000 sets motor 5's maximum allowed velocity

Motor Controller Variable Usage
The Animatics motor controllers provide for ten variables (a-j). Some of the variables are monitored by the higher level mechanism software but, in general, the variables are used internally within the low-level motor controller subroutines.
One can get the value of any variable with the askmotor command (described above) in conjunction with the Animatics 'R' command (eg. am 1 Ra).
The variables are used as follows :
a is set to 1 in the init subroutine and indicates that the init subroutine has been run since the last power-cycle or reset b is set to the backlash correction value c move settling time after which the brakes are set d the move destination whether absolute or relative e maximum allowed position error f maximum allowed velocity g used to specify which subroutine to execute on the next RUN; note that the 'g' values do not necessarily correspond one-to-one with the subroutine numbers h is set to 1 at the end of the homing subroutine and is used to determine if the motor has been homed since the last reset or power-cycle i an offset to the homed index mark which is an adjustment to the origin (O) command j a temporary variable currently only used at the end of homing in conjunction with the 'i' variable

Motor Controller Subroutines
There are three programs that are downloaded into the Animatics motor controllers. The shutter has a unique Animatics program because it's control parameters are significantly different. The pupil rotator has a unique program as well, mainly as it's motion subroutines do not require use of the brakes or backlash correction. The other nine motors all have the same motor program.
There are seven subroutines in the common motor program. They are:
C1 is the init subroutine which sets up the motors dynamics C2 is the motion subroutine which moves to some absolute position and performs a backlash correction. Note that brakes are released before the move commences and set after the move completes C3 is the homing routine which moves negative until the travel limit switch is encountered and then locates the first index mark in the positive direction C4 is a motion subroutine which does not perform backlash correction (not used operationally) C5 is the homing subroutine for the shutter (may be removed from the common program sometime) C6 is a motion subroutine for relative moves with backlash correction (not used operationally) C7 is a motion subroutine for relative moves without backlash correction (not used operationally)