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by jcrawfordor
1592 days ago
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A few little comments: 1) The HP 7440A does support hardware flow control (RTS/CTS) so no need for the OA trick. You might sometimes need a better serial controller. 2) HPGL is simple enough you don't totally need it, but Chiplotle is a Python library for generating HPGL that will save you some work: http://sites.music.columbia.edu/cmc/chiplotle/ 3) What the author calls a "DB-22 to DB-9 adapter" should be called a "DB-25 to DE-9 adapter." The shell size is kind of pedantic but the pin count confused me, because DB-25 is the spec standard RS-232 connector while a DB-22 is very much not! Actually if you get a USB serial adapter that's already a DB-25 it's more likely not to have issues with hardware flow control. Some of these plotters used HPIB instead which is a little annoying because the controllers are not so easy to find but they are out there and as a bonus you can use them with your old CRT storage oscilloscope too. 4) NOS pens for these plotters are stupid expensive, but I've had good success with using a lathe to produce some adapters to get it to grip Microliners. You will need a "case mod" of cutting out the section of the case between the carousel and the work area so the taller pens don't hit it. There are also 3D printed adapters you can find online but I've found the plotter is very sensitive about the diameter or it will fail to detect it has picked up the pen and retry a few times before going into error. My experience has been that 3D printed adapters aren't precise enough to avoid this issue but if you have a good printer or like a resin printer you might avoid this problem. 5) The plotter is very slow at linearizing curves internally even if you have the feature board, so you're better off doing that on the host and sending line segments than using the HPGL curve primitives. It's a print quality issue too because it keeps the pen down while calculating the next segment which tends to leave noticeable bleed at every node. |
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