From tom@belmont.astro.nwu.edu Wed Apr 12 22:14:00 2000 Date: Wed, 12 Apr 2000 17:53:19 -0500 (CDT) From: Tom RenbargerTo: Greg Griffin Cc: rfl@yerkes.uchicago.edu, Tom Renbarger , Giles Novak Subject: HWP commands Greg, Some basics about the hwp indexer and its documentation: The manual is ~ 5 x 8 inches, spiral bound, and has Intelligent Motion Systems and Software Reference Manual (among other things) on the cover. In discussing hwp mechanics, let it be known that 200 steps of the motor is one full revolution. There is a 15:1 gearing ratio between hwp and motor, so 3,000 motor steps is one full hwp revolution, and 250 steps is a 30 degree hwp rotation. The commands are, in general, case sensitive. In all cases of present interest, as it turns out, you will need to use capital letters. Here is some (a lot of, as it turns out) elaboration upon the message from Bob L.: > It's easily determined. Previous versions all share a common resource > file, where the parameters for the HWP are stored, so just switching > to an older code won't help. However, the last I looked, the parameters > were the same as used on the CSO. Tom is perhaps the only person > who knows how to change them other than me... > > What is the problem, exactly? > > Bob > > PS...use ResEdit or another resource editor on the mac to open > the sparo.rsrc file in the yerk folder. Look for STG# 128 (hwp init). > It should read: > > I100 > V150 > Y08 > 0 I is the command that sets the initial shaft velocity in steps per second. It is set with the command I#[cr] where # is the number of steps per second you want to start at. Optionally, a space can appear between I and #. Of course, [cr] is a carriage return. V is the final slew velocity. It is set with the command V#[cr], again with a space optional between V and #. For the short moves, V is never attained, as will be explained below. "Y08" should read Y 0 8. Y is the command to set the hold and run currents of the motor, expressed as a percentage of the maximum current the indexer can produce. Y is used with the command Y #1 #2[cr]. Spaces are needed between Y and #1, and #1 and #2. Use integers for this command. It is necessary to leave #1 as 0, but #2 can be adjusted upwards to test whether the problem is that we aren't giving enough power to the motor to turn each step it is asked to turn. The 0 is actually a capital O. That command simply sets the current position as the origin from which further moves are based. O[cr] is the syntax for this command. There is a way to change the defaults of the indexer settings with the S command. By entering an S command, you can change one default setting of I, V, or Y (among others) at a time by entering the command with proper syntax immediately after the S command. The K command sets the ramp up/ramp down parameters. It's units are steps/sec/sec. The command syntax is K #up #down[cr], where #up is the steps/sec/sec ramp up velocity, and #down is the ramp down rate. If you set either to 0, no ramping up (or down, as appropriate) occurs, and the motor turns at the V setting throughout the whole turn. The way things are currently set up, the 150 step/sec velocity is never reached for the short moves, as the K setting is K 10 10 right now. It does come into play for the long backward move. By setting either or both to 0, you can just play with the V setting. The K default can also be changed through the use of the S command. In addition to playing with Y #2, I would recommend also turning down V to see if slower rotation helps. The hope is that bumping up the run current will be sufficient. If we turn down V to 50, for example, that would mean a 10 second move between hwp positions, and a 30 second move from 150 degrees to 0. We'll try to get some manual pages scanned in tomorrow. If you have any questions (as there is a lot of information here to digest), feel free to send them along. I have assumed that you've figured out how to use the paddle, but if you have any questions about that, please ask those as well. Tom