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Testing
Check the cordless drill speed. Tach lists 1160 - 1162 rpm
The PLC/encoder combination lists 1166 to 1172 based on a 10 second sample time multiplied by 6.
That's not fast enough. I need to check if the electric motor can run 2500 rpm or so.
Use a small router ( 25000 rpm no load) with a variac to adjust the speed.
The coupling is a bit of an issue. I ended up holding the router up against a liner of plastic pipe on the encoder. Any type of solid mount ended up binding quite badly within a few seconds. The router vibrates since it is not centered well. The alignment goes bad and puts a load on the router, which slows. The router bit (old and dull as it is) starts to chew up the plastic pipe and the router starts to spin faster than the encoder ... and the test is done.
So I held the router with one hand, with the encoder shimmed and clamped. The other hand adjusts the variac and checks the rpm with a digital tach. It's a slow process. And not too very accurate!
So here are the results:
- 1236 - 1260 rpm on the plc/encoder. Measures 1211 - 1230 rpm on the tach
- 1560 - 1674 rpm on the plc/encoder. Measures 1730 - 1766 rpm on the tach
- 2040 - 2100 rpm on the plc/encdoer. Measures 2001 - 2012 rpm on the tach
- 2400 rpm (solid) on the plc/encoder. Measures 3318 - 3330 rpm on the tach.
This tells me that I have a measurement limit at 2400 rpm or a problem with my program that won't allow it to measure higher than that.
So I think that I can reasonably measure at least 2000 rpm, likely closer to 2300.
I took my router, mounted it on a piece of scrap wood, mounted that to the bench, and added a friction coupler to turn the encoder. After tightening things up to that the encoder turned, the coupler split. And so did the next one. I'm having trouble locating something that will fit into the router and will also fit into the 5/8 hole in the encoder hub.
The adventure will continue - and I'll post some pictures so that you can see what I'm actually talking about.
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