DIY Scanner Card for DAQ6510 - Page 1
Forum section: electronics / projects

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 16, 2024, 06:51:53 pm
content: I've seen a few different versions of scanner cards based around the K2000 that are supposed to also work with the DMM6500 and DAQ6510. However, I have not seen one setup specifically for the larger size of the DAQ6510 scanner card slots.I just acquired two 7700 scanner cards, that were labeled by the seller as "probably defective." My goal is to repair one of them, and use the second enclosure for a DIY scanner card. I will most likely just convert the board size to fit directly, however, I am interested in making some improvements and/or adding some features if possible.I'm primarily looking at this project version as a base (I believe it's voltsandjolts' design) :https://www.eevblog.com/forum/circuit-studio/example-project-20-channel-solid-state-scan-card-for-k2000-dmm/msg4625614/#msg4625614Has anybody confirmed if that project works 100% with the DAQ6510?Thanks,JoshETA: Probably final schematic attached.

author: voltsandjolts
author_rank: Unknown
timestamp: December 16, 2024, 07:10:08 pm
content: Quote from: KungFuJosh on December 16, 2024, 06:51:53 pmThat card is for the Keithley 2000 and 6500, it doesn't physically fit in the 6510 and probably wouldn't work electrically either. According toanother thread herethe 7700 card also uses a simple clocked data to shift register scheme to drive relays. But it has an eeprom with card type/serial number which you likely need to get the dmm to recognise it.Edit: There is much discussion on this card in the following posts. To save readers from trawling through it, here is a copy of the latest schematic I made. It gives a general idea of functionality, but KungFuJosh's schematic has more detail so be sure to refer to that also.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 16, 2024, 07:50:37 pm
content: Quote from: voltsandjolts on December 16, 2024, 07:10:08 pmGoogling implied that the K2000 cards theoretically work with the DAQ6510, but that could obviously be wrong. There are also SSR version(s) of the cards for the DAQ like the 7710, but I want to allow higher voltages than that. However, higher voltage isn't that important if I get one of these 2 cards working.I can try copying the EEPROMs on the 2 boards and see what that looks like. I'll see if one of my programmers can read them.Physically fitting would be the easier part. I already started measuring the 7700 PCB and will verify dimensions/mounting and create a new board outline. I also scanned the bottom of the cards for that purpose (attached). I have a laser, so once everything looks good, I can cut out a test card shape and verify if it fits in the enclosures / matches the 7700 cards.ETA: 1 of my 2 boards has an EPT 116-90054 connector on it. That part was easier to find than the other, but it looks like alternates are available anyway.Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: December 16, 2024, 08:03:22 pm
content: I don't think there is a schematic available for those cards, so it might be useful to make one, or at least partial schematic. The important parts being the clock/data/strobe (?) from the DIN connector (which pins?) to the series of shift registers / relay drivers. Also the DIN connector pins to the eeprom. That would probably be about it done.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 17, 2024, 02:49:40 am
content: This has a nice (at least 4 layers?) design. I'm not going to trash either of the boards until I know which one is better, though I have a good idea of which that is. Then I should be able to see the rest of those traces. This is a decent start though.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 18, 2024, 06:05:47 pm
content: Does anybody know how to tell the age of the 7700 boards based on how they look? I've seen green and blue PCBs, and both black and blue terminal blocks. Is that based on age, or random?Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 18, 2024, 06:53:22 pm
content: Here's a better image of the top with the connector removed. You can see the nice fat traces for the 2 current channels.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 18, 2024, 06:54:04 pm
content: Here's the less pretty back side.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 19, 2024, 09:58:45 pm
content: The "easier" part is done. The PCB mounting holes, outline, and connector are all accurate now in Kicad (I had to make a tiny adjustment to one mounting hole after this photo).When I have some more time, I'll trace the circuit a bit and see what's what.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 20, 2024, 02:03:38 am
content: Here's the 24C164WI EEPROM connections. Looks like they used one row for the chip, and the other row to do dabusiness.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 20, 2024, 04:49:30 pm
content: Quote from: voltsandjolts on December 16, 2024, 08:03:22 pmDo you have any tips on figuring those things out without the card connected to anything? Some of it you can see in the attached high res photos with the terminal blocks removed, but I don't know how to tell which is clock/data/strobe.The fattest 2 traces predictably go to the current section.Then 3 other larger traces go to 2 different relays where one of those traces (DIN row C pinleads to TP1 then a relay, then the input H/L followed by one side of the channel relays.The other two traces (DIN row C pins 10,12) go to 1 relay that then goes to the relays opposite the others connected via pin8.TP2 is connected to row A pins 1,7.TP3 is connected to DIN row C p14, which then goes to pins 2 to 7 of the LM35D temp sensors, and one side of the adjacent capacitors. DIN row C p16 goes to p8 of all the LM35Ds, and the opposite side of the adjacent capacitor.There are some tiny traces on the control side of the DIN that go to a small cluster of caps/resistors:Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: December 20, 2024, 07:18:00 pm
content: Quote from: KungFuJosh on December 20, 2024, 04:49:30 pmFor the 4094 shift registers, I can offer some guess work to help you get started:Pin 3 is the CLOCK - my guess is that same CLOCK signal goes to all 4094, so pin 3 of all 4094 should be shorted together. This signal may come from the DIN connector directly, or might be buffered through the 74HCT14 (U25).Pin 2 is the DATA in - the DATA signal will pass through each 4094, from pin 10 to pin 2 of the next 4094. The DATA for the first 4094 (pin 2) may come direct from the DIN connector, or might be buffered through the 74HCT14 (U25).Pin 1 is the STROBE - after all the data has been clocked through the 4094's, the STROBE signal latches that data to the output drivers of the 4094. My guess is that same STROBE signal goes to all 4094, so pin 1 of all 4094 should be shorted together. This signal may come from the DIN connector directly, or might be buffered through the 74HCT14 (U25). Or it may come from the 74HC123, which might generate a STROBE pulse after all the clock cycles are done....not sure.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 21, 2024, 12:07:20 am
content: Quote from: voltsandjolts on December 20, 2024, 07:18:00 pmThank you! That was an excellent start, but I'm still missing something here. This is what I could trace:14094 (all) p3 + U25 p9 connects to R67 in series with R66 to DIN p5.14094 (all in series in order from U1 to U4) p2 connected from previous 14094 p9.U1 (14094) p2 connects to U25 p1 + p5, also connects to R69 in series with R68 to DIN p3.14094 p1 I couldn't find any connections, and they're not shorted to each other either. My guess is the cluster on the back side might have something to do with that?Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: December 21, 2024, 11:53:56 am
content: OK, that all makes sense, apart from STROBE pin 1 of the 4094's, need to double check that. They must be driven from somewhere, possibly tied high, in which case the output enable (pin 15) might be pulsed by the 74HC123.Keep calm and carry on!Edit: OK, looks like the output enable (pin 15) is getting pulsed, so STROBE pins may be tied high. See attached.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 21, 2024, 09:46:03 pm
content: Quote from: voltsandjolts on December 21, 2024, 11:53:56 amThat schematic is not accurate with the resistors. The resistor pairs are in series (500Ω each). There's also a cap between each resistor pair that connects to ground.I'm drawing more on my schematic now.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 21, 2024, 10:57:05 pm
content: I can't figure out where R71 connects.Assuming I didn't screw anything up, the other parts look like this:

author: voltsandjolts
author_rank: Unknown
timestamp: December 22, 2024, 10:17:03 am
content: Quote from: KungFuJosh on December 21, 2024, 10:57:05 pmA dmm with fast continuity buzzer helps with this, drag a probe across the ic pins.Some more guess work from me... I think the STROBE signal is used to latch data in the shift registers, and also to trigger the HC123 monostable which momentarily drives OE to switch the relays.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 02:41:37 pm
content: Quote from: voltsandjolts on December 22, 2024, 10:17:03 amYup, and gold plated probemaster probes too. The issue is the 4-layers plus outer layers; it's hard to play the buzzer game with that one. The traces switch sides sometimes, and sometimes the via doesn't go all the way through, so it's difficult to see where it goes. And since it's an SMT resistor, I can't easily clip onto it to ignore that end while probing the back.ETA: I might solder a lead on to the resistor if I need to. 🤷ETA2: Now that I think of it, I'll raise the buzzer limit over 1kΩ first and see if that gives me something.QuoteNice! I'll test it out and see what I can confirm.BTW- I grabbed the data off the EEPROMs. Do you want to check it out?Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 04:19:29 pm
content: Quote from: KungFuJosh on December 22, 2024, 02:41:37 pmThat worked. I get 1k resistance from R71 to U14 p11, looks like it's via R150 (1kΩ) on the back.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 05:06:17 pm
content: Here's what I've got so far.Thanks,JoshETA: schematic with error removed

author: voltsandjolts
author_rank: Unknown
timestamp: December 22, 2024, 06:43:54 pm
content: Your schematic has U25 pin 2 joined to U14 pin 4 - please check as that's connecting two outputs together.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 06:58:48 pm
content: Quote from: voltsandjolts on December 22, 2024, 06:43:54 pmOops, good catch. That was supposed to go to U24 p4. I'll post an updated schematic shortly; I'm checking some other things right now.Thanks,Josh

author: Kleinstein
author_rank: Super Contributor
timestamp: December 22, 2024, 07:25:56 pm
content: There are 2 different types of relays: latching ones and non latching ones. These may need a different control - the HC123 may create the pulses in hadware, though it is also possible to have the µC in the DMM needs to do this in software.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 08:09:03 pm
content: Quote from: Kleinstein on December 22, 2024, 07:25:56 pmThey'reallmostlylatching EE2-3SNUH relays on this model. There is a command in the menus to open the relays in case they get stuck. I dunno how that's done from there though. 😉

author: voltsandjolts
author_rank: Unknown
timestamp: December 22, 2024, 08:11:08 pm
content: Two relays are non-latching, over by the DIN connector.EE2-4.5NUH SMD 4.5VDC SINGLE COIL NON-LATCHING

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 08:28:18 pm
content: Quote from: voltsandjolts on December 22, 2024, 08:11:08 pmOhhh, sneaky. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 08:47:51 pm
content: Looks like the 2 non-latching relays serve the rest of the latching relays. The DIN connects through them first.I marked off the sections for K1 - K20 on the back of the board.

author: voltsandjolts
author_rank: Unknown
timestamp: December 22, 2024, 09:22:26 pm
content: Quote from: KungFuJosh on December 22, 2024, 08:47:51 pmIn that case, the non-latching relays are likely called the 'backplane relays'. See attached.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 09:47:48 pm
content: Quote from: voltsandjolts on December 22, 2024, 09:22:26 pmComparing that to the traces looks like you're correct.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 22, 2024, 10:15:35 pm
content: Here's an updated schematic. I confirmed your relay connections as well. All were correct.Thanks,JoshETA: Outdated attachment removed.

author: TizianoHV
author_rank: Regular Contributor
timestamp: December 22, 2024, 11:40:09 pm
content: I don't know if this is helpful, but here's the analog pinout of the scanner board connector for my K2790 (same as the K2700 but with source). Since I don't have any boards, I soldered some wires to a connector so I could use the front/back switch.A "7702 compatible" board would be great because they are rare (and the K2790 doesn't support the 7700)

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 23, 2024, 12:06:19 am
content: Quote from: TizianoHV on December 22, 2024, 11:40:09 pmAFAIK, the only differences between the 7700 and 7702 is the automatic-CJC on the 7700, and twice as many channels on the 7702. Is the auto-CJC why it won't work?Does the K2790 specifically not work with the 7700? I know the regular K2700 does support it, though might require a minimum firmware version.

author: TizianoHV
author_rank: Regular Contributor
timestamp: December 23, 2024, 10:12:09 am
content: I don't own a scanner card but using the "SYST:PCARD1 C7700" command to emulate a 7700 card it returns an error. 2790 doesn't support termocouples, so probably that the reason. They are still selling it but there are no new functions.

author: voltsandjolts
author_rank: Unknown
timestamp: December 24, 2024, 05:36:51 pm
content: This might give you a head start for the cold junction mux...

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 24, 2024, 06:12:36 pm
content: Quote from: voltsandjolts on December 24, 2024, 05:36:51 pmDo we want to do all of that? At this point, I'm assuming I'll be able to repair and use at least 1 of my 7700 cards.My thoughts with this is a DIY conversion of the K2000 DIY card, or something similar that's compatible with the DAQ and probably also the 2700 series so other people can benefit...and also me if I can't fix one of them for some reason. 😉What do you think?Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: December 24, 2024, 06:30:45 pm
content: If your not planning to use thermocouples, then sure, no point in the added time in KiCAD or extra cost of parts for the cold junctions. But if you get 20mins to buzz out the signals so I can finish the above diagram, I'd appreciate it! I do a fair amount of temperature cycling of circuits and use K2000 and/or 34970A for scanning. With six CJ sensors, this card could offer more accurate thermocouple measurements...and provide an excuse to get a DAQ6510.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 24, 2024, 06:36:25 pm
content: Quote from: voltsandjolts on December 24, 2024, 06:30:45 pmOh, that's cool. As long as somebody benefits from it, I'm happy to do it.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 26, 2024, 07:12:50 pm
content: Here's what I've got so far. Please let me know if there are any silly errors. 😉ETA: Outdated attachment removed.

author: voltsandjolts
author_rank: Unknown
timestamp: December 27, 2024, 07:47:49 pm
content: Hey, thanks for that.1/ You have the same GND symbol on the CJ Mux circuitry but I suspect it's isolated from the GND of the other logic. I mean, for example, U7 pin7 should not be connected to U25 pin 7? The CJ Mux GND should come from the DIN. Please confirm.2/ The CJ Mux VCC should also be isolated from the other logic. It should also come from the DIN. I think.3/ U8 is shown with CLK, QP4 and QS2 connected to GND. This can't be correct because QP4 and QS2 are outputs, and the CLK is needed as an input. The CLK, DATA, and STROBE should come from U7 pin 2, 4 or 6. I think.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 28, 2024, 12:39:15 am
content: Pardon the laziness on the labeling, I've corrected that and added the DIN connections.I had U8 written in my notes for those grounds but it was supposed to be U6.I also added a connection from U7p6 to U8p3.Let me know if I missed anything else.Thanks,JoshETA: Outdated attachment removed.

author: voltsandjolts
author_rank: Unknown
timestamp: December 28, 2024, 09:20:48 am
content: OK, the signal flow is clear but I need some more connection tests. First of all, can you please find the connected pins for the connections in the green circle?Thanks.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 28, 2024, 09:35:14 am
content: VDD at the shift registers is the supply, so likely 5 V.I don't think it makes sense to have the Cext pins of both monoflops (U14) tied to GND. This would defeat the function.A few part of U24 are still open. E.g. Pin 9 and 10 need a signal to drive it - this could be from U14 (e.g. pin 4 or 13).

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 28, 2024, 09:59:06 pm
content: U14p15 (RCext) wasn't previously connected to anything in my schematic, but I traced it out and included it. R1 says 1403, which I assume should be 140k, but it's nowhere near that in-circuit.As always, let me know if I screwed something up. 😉ETA: Error attachment removed. 🙄

author: Kleinstein
author_rank: Super Contributor
timestamp: December 28, 2024, 10:54:01 pm
content: The Cext to GND seems to make sense with this monoflop version (a bit odd label there). A time constant of some 100 nF*140 K = 14 ms makes sense for controling the length of the pulses for latching relays.The in circuit measurement can be off for a 140 K range resistorconnected to an chip input, with possibly a shottky diode (at least suggested from the DS).

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 28, 2024, 11:12:30 pm
content: Oops. Not sure what happened there, but the other side of R1 connects to VCC, not pins 1 and 5 of U25. Does that make sense?I was more patient and measured R1 for longer and it climbed up much higher. 125k is where I got impatient again and moved on. 😉ETA: Outdated attachment removed.

author: Kleinstein
author_rank: Super Contributor
timestamp: December 28, 2024, 11:18:16 pm
content: A resistor to VCC is what the datasheet for the monoflop gives as the normal circuit. So the DIN A15 should be some +5 V supply.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 28, 2024, 11:44:02 pm
content: Cool, so then it should be correct now. I must have gone through the wrong via the first time I tried tracing it. There's like 1000 blind vias, so some things are tricky to follow.

author: voltsandjolts
author_rank: Unknown
timestamp: December 29, 2024, 08:33:12 am
content: Last bit of the CJ Mux - can you find where the connections circled in green are coming from?Likely from U14 / U24 / U25.Thanks.

author: voltsandjolts
author_rank: Unknown
timestamp: December 29, 2024, 08:01:55 pm
content: U9 pin 3 to DIN_A15 (VCC) is not correct. Pin 3 signal is likely derived from DIN_A3 (data), perhaps from U25 pin 2. (Are you sure about the U25a and U25c inverters in parallel, pin 2 joined to pin 6?)You have U25 pin 4 supplying a signal, but that inverter has no input at pin 3. Where does pin 3 come from? U24 pin 3?Also, relay drivers for K21 through K27 need connected to U4.Thanks!

author: Kleinstein
author_rank: Super Contributor
timestamp: December 29, 2024, 08:23:17 pm
content: It is still a bit unclear, how the other sides of the latching relays are connected. It could be 1 common driver.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 29, 2024, 08:30:40 pm
content: Much better! You were correct about U25, but it's pin 6 direct to R56. Not sure why that didn't work earlier. I must have swiped too fast. That makes much more sense now.I've marked (and corrected) some of the relays, and will post the U4 connections once I buzz those out.Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: December 29, 2024, 08:40:53 pm
content: Quote from: Kleinstein on December 29, 2024, 08:23:17 pmI suspectQ1 Q5 are involved, perhaps switching the other side of the relays to +/-.Also, maybe one bank switched at a time, not sure.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 29, 2024, 09:15:40 pm
content: It's gonna take a bit to buzz the rest of this out and then draft it in Kicad, so here, try and read my handwriting. 😉 I'll jump back on this a little later.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 29, 2024, 09:18:31 pm
content: Also, here's the corrected/updated schematic before adding more relay stuff.ETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 30, 2024, 01:03:38 am
content: Any idea on what this manufacturer part number is? It's a single diode instead of double like the others.

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 30, 2024, 02:29:43 am
content: Here it is with some more relay details.Thanks,JoshETA: Outdated schematic removed.

author: voltsandjolts
author_rank: Unknown
timestamp: December 30, 2024, 08:16:06 am
content: Quote from: KungFuJosh on December 30, 2024, 01:03:38 amYes, single diode, maybe this...

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 30, 2024, 04:14:40 pm
content: I added the part name to the schematic. Let me know if there are any corrections or additions you need added.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: December 31, 2024, 01:11:21 am
content: Looks like Molex 39543-0202 is a good option for the terminal blocks, and should fit inside the 7700 style enclosure with its 11.7mm height. They also have a good price drop when buying in quantity.

author: voltsandjolts
author_rank: Unknown
timestamp: January 01, 2025, 10:47:43 am
content: U25 stuff:1/ You have U25a (pin 2) driving the register STROBE signal, but U25a input (pin 1) is the DATA signal, which doesn't make much sense. Can you please check.2/ Where does U25b pin 3 come from? Maybe the AND gates U24?3/ U25 pins 10 through 13 not connected to anything? Should have inputs grounded at least, if not used.Thanks.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 01, 2025, 04:45:14 pm
content: Quote from: voltsandjolts on January 01, 2025, 10:47:43 am1) I'll check again before posting another schematic.2) U24p33) Correct, the inputs are grounded. No connection on the outputs.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 01, 2025, 04:55:32 pm
content: Here's what I did yesterday; I did not find any errors with U25.Thanks,JoshETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 01, 2025, 11:04:43 pm
content: This is better. K21 was correct, but it looks like K22's connection is determined via K21. Also found where Q1's Rs go (U4p13).Thanks,JoshETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 01:30:09 am
content: This has K21-K27 page maybe complete. K22 and K23 pins 3 and 10 don't appear to have any connections, so I marked them that way.ETA: Outdated schematic removed.

author: voltsandjolts
author_rank: Unknown
timestamp: January 02, 2025, 10:32:10 am
content: Does Q1p3 connect to DIN A15 (VCC)?Does Q1p1 connect to DIN A1 (GND)?

author: JK21
author_rank: Contributor
timestamp: January 02, 2025, 03:42:37 pm
content: What I found out:Testpoints (TPx) at backside:TP1 = ISOGNDTP2 = GNDTP3 = ISOVCCQ1p1 = GND= P12 = TP4Q1p3 is not connected to VCC !

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 04:01:31 pm
content: Quote from: voltsandjolts on January 02, 2025, 10:32:10 amYes, Q1p1 connects to GND. Q1p3 connects to Q5. I'll buzz it out and post another update.

author: JK21
author_rank: Contributor
timestamp: January 02, 2025, 04:18:44 pm
content: Quote from: KungFuJosh on January 02, 2025, 04:01:31 pmYes.It seems at KICAD page 3 the symbol for K21 is not right. Pin1 and pin 12 has to be exchanged. Pin 1 is marked at PCB.So pin1 is connected to Q7/Q48.

author: JK21
author_rank: Contributor
timestamp: January 02, 2025, 04:55:31 pm
content: Sorry, but unfortunately, this is the trap I know too: "Bottom view"

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 05:11:14 pm
content: Quote from: JK21 on January 02, 2025, 04:55:31 pmShit! Those bastards tricked me! 🤬🤬🤬WTF would they do bottom view for an SMT relay?!Apparently all the relays are backwards?? 🙄

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 06:09:51 pm
content: Corrected schematic attached. I cheated and made new symbols so I could copypasta them in place of the backwards symbols. 😉Please review for other stupid errors. Or just regular errors.ETA: Outdated schematic removed.

author: voltsandjolts
author_rank: Unknown
timestamp: January 02, 2025, 07:42:22 pm
content: P1 = TP4 = Q1p5,6,7,8i.e all latching relay coils have one side connected to Q1p5,6,7,8Have I got that right?

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 08:17:50 pm
content: Correct. I should probably mark that more clearly. What do you suggest?

author: voltsandjolts
author_rank: Unknown
timestamp: January 02, 2025, 08:23:11 pm
content: On my pseudo-schematic I have net names Vdriver and Vcoil.

author: voltsandjolts
author_rank: Unknown
timestamp: January 02, 2025, 08:38:27 pm
content: I guessed that U14 p7 goes to R2 C150 ...can you pls check.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 09:06:08 pm
content: Correct. Schematic attached.Thanks,JoshETA: Outdated schematic removed.

author: voltsandjolts
author_rank: Unknown
timestamp: January 02, 2025, 09:20:58 pm
content: I think R2 should go pin7 to VCC, not to GND?

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 09:40:14 pm
content: Quote from: voltsandjolts on January 02, 2025, 09:20:58 pmC150 + R2 are in parallel as noted. You can see the traces in the photo.U14p16 goes to VCC.Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: January 02, 2025, 09:50:37 pm
content: Hmm, OK, thanks.Looks like your schematic is just about complete, nice!

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 02, 2025, 11:21:36 pm
content: I removed some errors (duplicate IDs), and added the missing connections (or lack thereof).Please let me know if there's anything else needed. I'm going to look at the remaining random stuff (mostly on the back).Thanks,JoshETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 03, 2025, 01:33:11 am
content: This might be complete now. I added missing components from both sides of the board. I don't think there's any missing parts now, but, ya know. I have no idea if there are any missing connections. 🤷Thanks,JoshETA: Outdated schematic removed.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 03, 2025, 09:51:50 am
content: The resistors R62 and R63 don't make that much sense, at least not with the given values. An in circuit measurement could well give a wrong values.The circuit around the 2 non latching relays also looks odd - there should be supply connected to the pin 12 side, not just via the diodes and Vdriver. So maybe R62/63 go to the other side with a lower value.The VDD part from the 4094 should be connected to some 5 V. The capacitor values for C3,C9,C11,C14 are likely smaller as they are in parallel for decoupling. Chances are C4 is the same - it looks a lot like the upper end of C4 is connected to something, like a supply.

author: voltsandjolts
author_rank: Unknown
timestamp: January 03, 2025, 12:31:12 pm
content: I don't think the current measurement relays are wired correctly. See the schema from the manual:https://www.eevblog.com/forum/projects/diy-scanner-card-for-daq6510/msg5757233/#msg5757233The idea is the current measurement channel is shorted ( e.g. CH21 Hi to CH21 Lo) by relays until the measurement is being taken, at which point the current is re-routed through the dmm. This has an unfortunate side effect of momentary disconnect as the relays switch over.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 03, 2025, 12:55:21 pm
content: Ideally they would use make before breake relays. However these are rare. Another option could be to have additional protection diodes before the relays, at least as an option.

author: voltsandjolts
author_rank: Unknown
timestamp: January 03, 2025, 02:00:45 pm
content: Quote from: Kleinstein on January 03, 2025, 12:55:21 pmHmm, this card has two DPDT relays per current channel. They could perhaps be wired to function as make-before-break?

author: Kleinstein
author_rank: Super Contributor
timestamp: January 03, 2025, 03:57:34 pm
content: They seem to use relay contacts in parallel, to get high current carring capability. It may be possible to ogranize the contacts different: not one relay for the low side and the other for the high side, but so that 1 relay alone would work and the 2nd one in parallel. When than one relay is delayed a little, one would get a kind of make before break with only 1 contact active for the short cross over time.Getting the delay with the latching relays can still be a bit tricky.Another option would be to have separate relays for shortening the current paths. This would however need also a different control for 2 more relays.As shown in the last plan, the directs short at the relays is connects between the channels. I don't think this makes sense. This are links between the pins 3 of the relays K24,25,26,27. It would make more sense to have them not connected.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 03, 2025, 04:16:53 pm
content: Quote from: Kleinstein on January 03, 2025, 09:51:50 amR62/R63 are labeled 1370 and measure ~137Ω in circuit, so that's correct. I can't comment beyond that, as you both understand what's going on better than I do. 😉4094 Vdd (p16) appears to be connected to VCC, nice catch.I agree, most of the capacitance values are unreliable since they're all measured in circuit. Some of them were standard enough to be believable, but otherwise, not so much. C3, C4, C9, C11, C14 are all parallel, so I would guess closer to 40 or 50µF depending on tolerance. Unless one of my two cards are unrepairable (is there such a thing?), I won't be removing anything to measure out of circuit.Take a look at the attached photos of the non-latching relays, and let me know if you see a trace that I haven't been able to find. That whole section is confusing, but I mapped it out pretty well...besides reversing the numbers, but that was an easy fix. 😉ETA:Downloadthe high-res photos in Reply #10 if you'd like a better view of the traces.ETA2: Now that I think of it, that means C4 is also missing a connection to VCC. I'll update shortly.ETA3: Schematic updated.Thanks,Josh

author: Kleinstein
author_rank: Super Contributor
timestamp: January 03, 2025, 04:35:07 pm
content: From the pictures it look like R62/R63 are connected to the other side of the relay. This would also make sense: the resistors would reduce the current in hold state and Vdriver would provide extra current for engaging the relays.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 03, 2025, 04:56:06 pm
content: Quote from: Kleinstein on January 03, 2025, 04:35:07 pmOne side of R62/R63 is direct to VCC, and VCC does not connect directly to K22/K23. The other side of R62/R63 connects to p1 as shown in the schematic. p12's lowest Ω value to either R62/R63 is the same as the value between p1 to p12 per each relay.I still can't see or trace any connections to p12 that aren't noted. If you have another idea to check, please let me know.Thanks,Josh

author: Kleinstein
author_rank: Super Contributor
timestamp: January 03, 2025, 05:18:49 pm
content: From the photos it looks like:Pin 1 (up in the pictures) is connected to the diodes (e.g. CR24+CR27) and R62 or R63Pin 12 (down) is connected to the transistor (e.g. Q50).So the difference to the shematics is where the transistor and diodes connect.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 03, 2025, 05:52:52 pm
content: Ah, nice catch...again. 😉Confirmed, and schematic updated. Hopefully that's the last relay error.I'm guessing that mistake predated the relay reverse goof up.lol, actually, that was the only part that wasn't a mistake before it was reversed. 🤣Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: January 03, 2025, 07:29:18 pm
content: See attached...Regarding the current relays, the connections circled in red don't make sense (shorting CH21 to CH22). The connections shown in blue would make more sense (shorting CH21 Hi to Lo and CH22 Hi to Lo, when those channels not selected).

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 03, 2025, 07:41:10 pm
content: Something is wacky there. I'll trace that section again.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 03, 2025, 07:55:06 pm
content: Yup, nice catch. What's the score now? 😉Updated schematic attached.Thanks,JoshETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 04, 2025, 09:14:16 pm
content: Kicad changed U16, C30, and C31's numbers when I copy/pasted it. That's annoying. I'll post an updated schematic later, but not until I'm done reviewing stuff.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 05, 2025, 01:29:14 am
content: I've (probably maybe) corrected all the annotations. 🤷I also added the test points and VR1 (unpopulated).ETA: Corrected terminal connection order/orientation.Thanks,JoshETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 05, 2025, 11:29:59 pm
content: It looks like they have some interesting design choices here. Like this looks like middle-layer shielding around the terminal connections.

author: voltsandjolts
author_rank: Unknown
timestamp: January 06, 2025, 08:04:33 pm
content: Rather than shielding, I suspect it's more likely an attempt to create an isothermal area at each channel terminal pair, to help improve thermocouple accuracy. It may also assist keeping the adjacent isothermal area (with the cold junction sensors) closer to the terminal block temperature, while maintaining electrical isolation of course.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 06, 2025, 08:43:19 pm
content: Thermal pads do make more sense. The board has lots of interesting things going on for the thermal junk. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 09, 2025, 06:47:02 pm
content: I found issues around Q47 / Q48. Will update when done.ETA: Never mind. The stupid footprints had the wrong pins, but the schematic should be fine. I'll post an updated version soon anyway.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 10, 2025, 02:50:45 am
content: I was avoiding messing with the PCB layout, but it helped find a few errors. The 4-layers thing is kinda fun. I dunno if I'll ever finish it, but it's very effective for procrastinating other things. 😉Better schematic attached. ETA: ...and removed.Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: January 10, 2025, 01:12:55 pm
content: You're making good progress, well done.On your schematic you have C4, 9, 10, 11, 14 labelled as 188uF but they are small ceramics, likely 100nF. When measuring these you were also measuring other capacitors on that power rail, including C16 220uF.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 10, 2025, 03:11:25 pm
content: Thank you.Yes, I know, but I don't want to change the value in the schematic without measuring a reliable value.I'll have my DAQ back today, and then I'll be able to see what condition my cards are in. After I figure out which one is better, I might remove some capacitors from the other board and get more accurate values.

author: voltsandjolts
author_rank: Unknown
timestamp: January 10, 2025, 03:29:23 pm
content: Are you a Rick Astley fan?!Seen your QR code

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 10, 2025, 03:31:03 pm
content: I have no idea what you're talking about, I'm completely innocent. 😇

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 10, 2025, 03:32:55 pm
content: VCC to ground parallel caps:C4,9,10,11,14;C16 is labeled 220uFOther uncertain values:C31C150C23,24,25,26,29,32,33,34Anything else I should add to the list that I missed?

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 10, 2025, 08:55:03 pm
content: I got my DAQ back, and the better of the 2 cards installed and running. The attached card's data seems a good candidate for some light slaughter...assuming the data is correct.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 11, 2025, 03:20:57 am
content: Well, it appears there are 2 values of non-polarized caps. The 805s appear to be 47pF, and all the 1206s appear to be 100nF.I removed a bunch of them to confirm, including from the CJC stuff that I thought were 1uF, but no, just more parallel caps. lolI'll post an updated schematic when I'm done updating it.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 11, 2025, 03:34:43 am
content: Here's the updated schematic with (probably) correct capacitor values.ETA: Outdated schematic removed.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 11, 2025, 09:05:52 am
content: It must be a rather old design when they use 1206 size for 100 nF decoupling capacitors. Today 100 nF would likely be 0603.For the decoupling the exact value does not matter 1 µF capacitors would work as well.47 pF sounds reasonable for the small filtering capacitors.The relay counts are really high. So the contracts may no longer be good and reliable. This could be a reason for the cards to be removed and sold as defect.For the screw terminals is could be relevant how well they work with really thin wires. Thermocouple wires are often rather thin (e.g. 0.2 mm).

author: voltsandjolts
author_rank: Unknown
timestamp: January 11, 2025, 09:57:41 am
content: Quote from: KungFuJosh on January 10, 2025, 03:32:55 pmMinor stuff:R60 R61 are marked as 4221, but I think this is the resistor marking, which means 4220 Ohms.In general, component values on schematics don't have decimal points, so instead use 1K5, 6R8, 4n7 etc. Old fashioned way to avoid missing the small decimal point. Just my personal preference.But yeh, it's done, thanks for your help with this. My (probably) final pseudo-schematic attached. If you want to tidy up this thread, I'm happy to delete my posts, we can make it look like we did it all in 3 posts here

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 11, 2025, 04:40:09 pm
content: Quote from: Kleinstein on January 11, 2025, 09:05:52 amYes, the design is copyright 2005, so that may have something to do with it. However, I would guess they were also considering the voltage limits of the caps, and the 1206 is 4.5x more robust compared to 0603.QuoteOnly the card I posted in this thread was that high. That's also why I didn't mind risking damage by removing parts to measure. My other card is much better (posted in the DAQ / DMM thread). I did have to repair the better card, and I replaced all the screw terminals as well. I did some quick testing, and it works fine so far.QuoteI used Molex 39543-0202, which can go down to 24AWG. 0.2mm is 32AWG, and Mouser doesn't list anything smaller than 30AWG in their search feature. The biggest restraint with the terminal blocks is that they need to be 45deg angle, and max height under 12mm to fit in the case.OTOH, I would keep what I used, and run to a breakout box like I made, but with screw terminals for thermocouples. The Mueller BU-P6883 is a good candidate for a nice combo jack.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 11, 2025, 04:54:27 pm
content: Quote from: voltsandjolts on January 11, 2025, 09:57:41 amDamn it. I thought I corrected all the resistor label values. I guess missing 2 isn't bad. I wrote them out that way then verified before marking them in the schematic because some brands of resistors label things differently.QuoteThat's not my preference. I did notice it in your schematics. I know a few other people that share your preference, but I like decimal points better. I've also never seen that used by major companies. For example, the attached Tek schematic uses decimals. Another classic brand that follows that structure is Neumann (also attached), but they're across the pond, so they used commas instead. I'm not suggesting you change, just pointing out I'm not alone in my preference. 😉QuoteNo problem, it was entertaining & educational procrastination for me. 😉 I wouldn't worry about cleaning the thread, but if you have a schematic with an error on it you feel like removing...but I think I had most of those. lolAre you going to design something with SSR?

author: voltsandjolts
author_rank: Unknown
timestamp: January 11, 2025, 05:26:19 pm
content: Quote from: KungFuJosh on January 11, 2025, 04:54:27 pmWell, I need a DAQ6510 first, but yeh, my preference is for SSR. The downside of tiny leakage makes no difference to my use case, and they're generally quieter!I'll put my latest schematic in the second post of this thread, so folks don't have to trawl through to find stuff. Might be an idea to keep a copy of your latest schematic in your opening post.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 11, 2025, 05:39:15 pm
content: I definitely like the idea of quieter / faster SSRs. Hurry up and get your DAQ! 😉I missed R4/R5 also, so here it is all corrected.Thanks,JoshETA: Outdated schematic removed.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 11, 2025, 11:29:57 pm
content: I figured it out. I also destroyed some small traces tearing off a couple relays, but whatever.It was impossible to figure out otherwise between the 4 layers, and the latching switches. You can see the slight change that makes much more sense now regarding K21/K22 and the Sense H/L screw terminals.ETA: or I could have look at your updated schematic too. 🙄🤣🤣ETA2: Outdated schematic removed.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 12, 2025, 03:14:29 am
content: Here's some high-res photos without those pesky relays in the way. 😉

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 17, 2025, 08:36:28 pm
content: I generated a BOM and found a couple value errors with caps in the previous version. This ishopefullythe final version. 😉

author: voltsandjolts
author_rank: Unknown
timestamp: January 17, 2025, 09:23:38 pm
content: There is never atruly finalversion!

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 17, 2025, 11:27:04 pm
content: Quote from: voltsandjolts on January 17, 2025, 09:23:38 pmThat's true

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 18, 2025, 12:31:35 am
content: Can somebody double check and see if 24AA16H-I/SN is a suitable replacement for the AT24C164WI? Seems like it should be fine to me, or suggest something else if you think there's a better direct replacement option?

author: voltsandjolts
author_rank: Unknown
timestamp: January 18, 2025, 06:59:33 am
content: On the scan card, address pins for the eeprom are wired to the DIN connector, which suggests that the device address is determined by the card slot. In the DMM the address DIN pins will be tied hi/lo differently for each slot. This allows one I2C bus to talk to the eeproms on all installed cards.But the datasheet for 24AA16H saysQuoteSo it ain't gonna work because it has no way to set the address by external pins.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 18, 2025, 04:40:18 pm
content: Nice catch, thanks.It looks like CAT24C164WI-GT3 is a better choice...or am I missing something again? 😉

author: voltsandjolts
author_rank: Unknown
timestamp: January 18, 2025, 07:36:41 pm
content: There are many EEPROM varieties which can make it tricky/time consuming to select one. This CAT24C16WI-GT3 won't work either because it doesn't use the external address pins, only the smaller capacity versions use them. Try again, third time lucky maybe!

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 19, 2025, 12:48:22 am
content: Quote from: voltsandjolts on January 18, 2025, 07:36:41 pmThe datasheet for the CAT24C164-D series shows both, doesn't it? I obviously don't understand these chips well enough.ETA: Sonofabitch. I thought I pasted the CAT24C164-D, but I guess that's obsolete, so Mouser switched me to the other. Am I right that the CAT24C164-D version is okay? Or is that fargin icehole also tricking me? I know it's not available, but I need to know what I'm missing here.Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: January 19, 2025, 07:03:13 pm
content: Quote from: KungFuJosh on January 19, 2025, 12:48:22 amYeh, that would work but, as you say, obsolete/unobtanium.I have a look at quick search but getting one with a usable addressing scheme seems...tricky.Worst case would be making some small mcu emulation of an eeprom, but hopefully it doesn't come to that.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 19, 2025, 07:32:07 pm
content: One may be able to use a larger capacity EEPROM version if this helps. This could extend the options.

author: voltsandjolts
author_rank: Unknown
timestamp: January 19, 2025, 08:14:56 pm
content: The problem is the obsolete eeprom compares specific bits in the i2c control byte with it's three address pins. To be compatible, any replacement has to compare those same i2c bits in the control byte and have just the one further address byte. Which limits the options to 16kbit devices, as all larger devices have another address byte, AFAICT?

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 19, 2025, 10:20:30 pm
content: What about this guy: 24LC515-I/P

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 19, 2025, 10:23:20 pm
content: This one also looks interesting: 24VL024/P

author: voltsandjolts
author_rank: Unknown
timestamp: January 20, 2025, 04:52:52 am
content: Quote from: KungFuJosh on January 19, 2025, 10:20:30 pmThis has control byte plus two address bytes, too many. Also bit positions are wrong for address pin comparison, and only two pins are used for the comparison, not three as required.Quote from: KungFuJosh on January 19, 2025, 10:23:20 pmThe bit positions are wrong in the control byte.

author: voltsandjolts
author_rank: Unknown
timestamp: January 20, 2025, 05:01:25 am
content: The attachment summarises the required addressing scheme of the original 24C164 eeprom, as used on your 7700 card.I just noticed the oddity of the A1 selection pin being invertedThat is a PITA, because any replacement device must also have this inversion so the dmm can address the correct card slot. So, if we found another eeprom which was same addressing scheme but without the inversion, we would need to invert the input to it's A1 pin. FFS.Take good care of the eeproms you have on the old cards. You may need them for your new card card build.Maybe need to find some old stock of 24C164 (or CAT24C164 which also has the A1 inversion).Edit:Last resort?https://www.ebay.com/itm/266393289454

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 20, 2025, 04:18:21 pm
content: Quote from: voltsandjolts on January 20, 2025, 05:01:25 amI saved the chip from the card I trashed. But realistically, I will likely have no actual need for another card. The 7700 card in my DAQ needed repairs, but it's working great now and has low enough counts on the relays. The attached screen captures are from a 10V ref without any warmup time, and with kinda wacky connections to it. This project is just entertainment for me at this point. 😉To make a direct clone will cost about $200 or so per each card including PCBA service from JLC (minimum 2). I dunno if that's worth it or not.QuoteMaybe other options:https://www.ebay.com/itm/226337604021https://www.aliexpress.us/item/3256802731765222.htmlhttps://www.ebay.com/itm/196758622535

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 20, 2025, 04:37:46 pm
content: Can you post the complete datasheet for the AT24C164WI? I can't find one.I'm curious about the CAT24C256WI, but I dunno about the address inversion thing, or if the size is an issue.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 29, 2025, 06:05:06 pm
content: To answer my own question, no, CAT24C256WI will not work as is. I assume because of the addressing. Copying the dumped data from an original chip was no issue, but the card is not detected with the CAT24C256WI chip installed.Is this something we can overcome by changing connections to pins 1 - 3, or is it simply not going to work?Thanks,Josh

author: voltsandjolts
author_rank: Unknown
timestamp: January 29, 2025, 07:33:52 pm
content: Yeh, not gonna workThe required addressing scheme is given in my reply #131.The CAT24C256 has an extra address byte.Stick with your old eeprom's for now, or buy old stock of them from the ebay links we mentioned. PITA.I wonder if the newest cards have a different but equivalent part...or maybe keithley did a lifetime buy on those eeproms.

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 30, 2025, 12:39:46 am
content: I Just found this one:https://www.ebay.com/itm/175155947142

author: KungFuJosh
author_rank: Super Contributor
timestamp: January 30, 2025, 03:14:25 pm
content: Finally found a datasheet.

author: KungFuJosh
author_rank: Super Contributor
timestamp: February 08, 2025, 09:10:30 pm
content: Quote from: KungFuJosh on January 30, 2025, 12:39:46 am...and they work. They have a tiny hidden notch over pin 1. That was cute.First I copied the original data from the crappy card, and it read that fine (as seen in the screenshots).Then I cleared the buffer, and wrote over the chip with a new serial number - 8675309. It also worked fine. It gave a warning about the relay count accuracy since I probably pasted too much back onto it...but it corrected it (also pictured). Then I ran 9 tests, and it recorded that too; despite there not actually being any relays installed. 😉Thanks,Josh