thanks for the reply, mark.
how did you know that the rs232 port is isolated? I can't find anywhere that says that and can't find a schematic, either.
No, problem! Several reasons: I looked at it and I can see the isolators followed by a MAX202 driver, I measured the resistance from the front terminals to the pins on the RS232 port (readings are in the Mohms), I applied 70V to the front terminals and did not see it on the RS232 pins, and finally the RS232 ground pin (pin 5) is connected to the instrument case. But you're right, they *should* say this in their datasheet somewhere since a lot of their competition doesn't do it.
I don't have time to do a tear down, but I did take some pictures of it below. You can see the isolators in one of the photos. You can't see the RS232 port on the inside shot, but it's under the power entry connector. That little board up top near the back is the optional GPIB.
what did you use for a programming reference? the user guide does have some scpi commands inline in the manual, but they refer to a different manual that is nowhere online or findable. I will call array to try to get it, but if you found the scpi command ref for this box, I'd love to get a copy.
I had to ask Circuit Specialists for the "SCPI Programming Guide" and they in turn got it from Array. Most of the commands, though, can be gleaned from the user manual since they embed the commands with the description of front panel operations. If you want, shoot me a PM and I'll mail you what they sent me. It's in .doc format.
there are a few places that sell this model series and they are in the US, which is great for returns or calib/warranty work. its a huge buzz-kill to have a DOA unit and have to reship back to china; either now or later. I'll pay more just to deal with a US distributor and not hassle with expensive international shipping. (this is one thing the chinese need to learn to really be able to break into the world market; they need LOCAL distributors so that people like me will have less fear, re: future service).
I agree in general, and in this particular case I'm hoping Circuit Specialists will do a good job. I can't claim I've stressed them with any really awful technical issues with their products, but so far they've done fine on this unit and on other things I've bought from them in the past.