rahul wrote:
> Yours is probably SN75188, the TI variety of MC1488.
This looks good. I did get data on the MAX 1488 which is listed as an alternative for the MC1488/SN75188. So now all I have to do is find an alternative for the SN 75152.....and why the <expletive deleted> used that instead of the 75189....
BTW, Pins 1 & 14 are linked on these chips, implying the +/- 12V that was suggested. The pins that go to +5v are inputs ( the various "A" inputs)
Pieter Hoeben wrote:
power surges came and went, and now it won't communicate with the outside world.
I think you have had some major currents flowing through ground and electronics.
Thanks for pointing that out :). The motor blew - didn't I mention it?
Note: if you connect a PC that is grounded with
a machine, you have made a very large loop that will pickup
magnetic fields, and induce currents in the ground. This can
destroy everything.
Yes...That's what the fools have done. No wonder the things blow up.
There's about 500 feet of cable, and most if it is nicely coiled on top of a cabinet in thew boss's office. It all helps.
So before using your machine again after repairing (using info of other emails), I would suggest optical isolation. Or place the PC close to the machine, and connect it to the machine's power.
Pressure of work governs common sense at the coal face, Pater. This guy will be running as soon as he can, even if it was on fire :-/.
In machines we made, we often used "opto-link", a plastic fibre cable, with some connectors and adapters, reasonably cheap and very reliable. The opto-coupler with the highest max voltage available! The only minus is that I hate adaptors (just look behind my PC, and you'll know why, adapters for: scanner, USBhub, router, palm, isdn-modem, HP jetdirect, fotocamera, batterycharger, bankcard reader, USB harddisk, videocamera, digital microscope, "normal" phone charger, GSM charger, eprom-eraser, programmer).
being a cheapskate, I don't have half of those adaptors behind my pc :-). But I take your point about an optical link.
If you have a circuit for the optical RS232, I'd appreciate it, as it will save me thinking. I'll build a few.
The easiest way to optically isolate machines is by current loop, or by opto-couplers in the RS2323 signal path. Email me if you want some info or schematics. I made this before.
--
With Best Regards,
Declan Moriarty -- Author: Declan Moriarty INET: [EMAIL PROTECTED]
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