PM9548 IEEE Interface for Philips PM6304 RLC Meter - Page 1
Forum section: electronics / testgear

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: May 16, 2015, 05:23:37 pm
content: HI all,i'm currently refurbishing a really nice PM6304 with a PM9548 IEEE interface. As this interface is pretty much useless for my applications, i'd like to kinda retro-fit the PM6304 with an RS232 Interface and ditch the PM9548. Looking at two ways to accomplish this:1) try to figure out how the PM6403 talks to the IEEE interface and roll my own isolated RS232 interface.this is currently hampered by the fact that i can't find any data about the two ICs marked OQ0300P.question: what is this chip? where can i get a data sheet?2) swap the IEEE against a suitable RS232If anybody is willing to trade a suitable RS232 against my IEEE, please drop me a line.Many thanks in advance,Hans

author: artag
author_rank: Super Contributor
timestamp: May 16, 2015, 05:43:04 pm
content: It looks as though it's got an opto-isolated interface, 4 bits one way and two the other. This doesn't correspond to any HPIB controller I've ever heard of, so it's probably talking to a custom microcontroller. the RS232 version of the adapter is probably the same except for a different microcontroller and buffer (though if you're really lucky, they could be using opto-isolated RS232 - the native processor might handle an RS232 interface and this board converts it to HPIB).If you examine the signals on the optos you might be able to reverse-engineer the protocol. But the quick and easy route is probably to put an hp-rs232 converter on the outside. Either an old converter box (sometimes found at junk sales) or one of several hpib-usb converters.

author: dom0
author_rank: Super Contributor
timestamp: May 16, 2015, 05:52:12 pm
content: OQ0300P is probably just a transistor array to drive the couples / logic inputs.I personally wouldn't break the interface but rather build my own on some perfboard, the form factor of the board is rather large, so that shouldn't be an issue and couplers are cheap. Also no edge connector but a standard 2.54 mm header, which makes this even simpler. After analyzing the interface you can sell the option again for someone who has a use for it. Everyone wins.

author: kada
author_rank: Contributor
timestamp: June 14, 2015, 04:39:29 pm
content: I uploaded service manual with schematicsthere(thanks toTiN).I hope this will help.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 14, 2015, 06:07:02 pm
content: I have two of the PM6306 RCL Meters.One of them with IEEE interface and one of them with the RS232 and I would suspect that the interface cards are the same as in the PM6304If it helps you, I can open both units and take a picture of the interface cards.I never got the GPIB interface to work on the one instrument, but I was able to use the RS232 port very well on the other instrument.Controlling the instrument settings and getting continuous data stream from the PM6306 was possible.

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: June 14, 2015, 07:00:35 pm
content: Quote from: kada on June 14, 2015, 04:39:29 pmthx 1E+6! YMMDhans

author: Le_Bassiste
author_rank: Frequent Contributor
timestamp: August 10, 2015, 04:05:41 pm
content: just received a cheap GPIB/USB which does the trick. case closed.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 15, 2015, 01:16:55 pm
content: Quote from: Le_Bassiste on August 10, 2015, 04:05:41 pmWhat software do you use to control the PM6304 through the GPIB port?