The Ohio State University College of Mathematical & Physical Sciences Department of Astronomy

Attendees: Darren DePoy, Jen Marshall, Dan Papallardo, Tom O'Brien, Mark Derwent, Paul Byard, Jerry Mason, Ralph Belville, & Rick Pogge

With holiday travel, ice storms, the start of the new quarter, more travel, and the usual fuss of getting a new year on track, this is the first formal MODS meeting of 2005. During Winter Quarter, we will be meeting weekly at 3pm on Tuesday afternoons in the Conference Room, with gaps for travel, etc.

Mark has been working to expediate the delivery of the MODS1 framework, delivery now delayed because of problems getting it painted. Ralph has designed a rigging for lifting MODS.

We have secured Wagner Crane & Rigging as the moving contractor. They will load the unit onto a double-drop low-boy truck at Indian Creek, transport it to OSU (securing all necessary permits), and unload it and install it in the high-bay shop. MODS just fits onto the lift into the "pit" outside the shop, and is then turned and inserted into the building long-ways through the door.

In the meantime, we are preparing the shop space following the plan worked out by Andy Krygier and Mark. We will start reconfiguring the shop 2 weeks before the scheduled delivery, clearing the floor. Once MODS1 is in, we will move various assembly equipment back into the area around the work floor.

Tom & Mark reported on progress fabricating various parts for MODS:

1. CNC mill work on the main parts for all 4 grating select turrets is done, and we have completed assembly of 2 of the turrets (welding and bolting). One is already anodized, the second will be sent in the next anodizing batch. The remaining 2 turrets are awaiting welding.

2. Dave has finished all of the invar trusses for the MODS1 Red Camera, and is making excellent progress.

3. The machined parts for both AGW stages (MODS1 and MODS2) are in hand and the first unit is being assembled. Some minor rework is required, but otherwise they have gone together very well.

4. The Calibration Towers for both MODS1 and MODS2 have been assembled, tested, and are being disassembled preparatory to anodizing. The only parts we need are the masks for the folding flat.

Some extra hardware for the AGW stages to use them for optical alignment testing of MODS has been designed and will be going out for fabrication.

Of the remaining design work, the one that has not yet been started is the design of the instrument enclosure. This depends on the arrangement of electronics boxes and other details. We will also be designing a construction enclosure to be used during the integration and testing phases to keep dirt off the instrument. For the individual subassemblies on carts (cameras, grating select turrets, focal-plane assemblies), we have designed fabric covers to put over them while in storage. Andy Krygier has identified a local boat-cover vendor that we are asking to bid on the work.

Ralph is working on drawings of sheet metal coverings for various of the subassemblies (collimator, big optics, etc.) and is tasked with identifying likely sheet-metal vendors.

No news on the main MODS optics from Steve Miller at Steward Mirror Lab. Paul will be trying to contact him.

In purchased optics, we have taken delivery from JML of the red folding flat mirrors, and the fold mirrors and lenses for the calibration system.

Paul has sent out bid packages for the bypass gratings used by the image motion compensation system. These are machined optics that produce about 15 orders of laser spots with a given angular separation. Only a small number of vendors make these particular devices, and we're asking for bids from most of them. So far 3 of 4 vendors have acknowledged receipt of the bid packages. One has already put in a bid for 20 units plus one-time design and tooling costs. Paul will be contacting this firm regarding the design study.

We have received modules from WAGO for the I/O electronics. This includes I/O modules (e.g., for reading the IMCS quad cells), RTD modules for temperature sensors, relay control modules for operating power supplies (e.g., calibration lamps and IMCS lasers), etc. We are still waiting to receive the "terminator" blocks needed to assemble and power up the units. These look like an excellent modular solution for us.

Dan Papallardo has been tasked with evaluating the WAGO I/O modules and researching our motion control systems issues, particularly the choice of motion control units. The latter is becoming a critical issue.

We had intended to adopt the Applied Motion Products Si motor controllers that we have previously deployed in two filter wheel systems, but in testing late last year, they failed to perform to specifications, in particular their limit switch recovery mode was very undesirable (it powered off the motor, rather than dropping to a power-positive idle state, allowing the mechanism to free slip). Iterations with Applied Motion's technical support people led us to conclude that the issue was intrinsic to their design, and so we cannot use them in MODS (though we will continue to use them in other filter wheel systems as the limit assertion recovery problem is not an issue in those rotary systems - no limits to assert).

We are currently reviewing motor control options, and are looking in particular at two units: The MicroLYNX controller from IMS, and a CANbus-based system from Copley Controls.

We have two MicroLYNX units in hand (we have used these controllers on the LBT Aluminizing system to operate the gate valves), and Dan will be setting these up to test in the lab this week. These units have a lot of very desirable features: rich command set, a daughter-board system that provides easy expansion of I/O ports, and they are serially addressable devices, so the software control architecture should be relatively simple to implement using networked serial-port servers (what we had been designing to earlier and have already extensively prototyped in recent instruments). The issue with MicroLYNX is that Bruce reported a problem with them producing sharp, milli-second scale current pulses when idle, which is unacceptable for operating in proximity to the CCD system (it would be substantial noise source). That, however, was with earlier revisions of the controller. Dan is tasked with setting up the new controllers as before and seeing if he can reproduce this pulsing problem, and to contact the vendor and try to understand it if so. We expect a report in a week or so.

We have ordered evaluation units from Copley Controls, but delivery is now delayed until late February according to the vendor. In the meantime, Ray Gonzalez has been tasked with getting the software documentation from Copley for their CML libraries and CANbus/CANopen system, and evaluating what that gets into. Adopting a CANbus-based system like the Copley units would be a major departure from our previous motion control systems, and so we need an assessment of how much effort this will require. Ray is doing the work on that.

Overall, adopting a motion control system for MODS is close to becoming a critical issue, especially for software development. We need to get this on track, and 3 people have been tasked with various aspects of the problem (Dan, Ray, and Rick) to report on at future meetings.

The next Progress Review for MODS will be on Monday, March 7th. This will be a joint review with the LBTPO and TSIP office, the latter represented by Todd Boroson and Mark Trueblood from NOAO. Kristy is taking care of details.