Rheodyne Injector + Dionex - pinouts?

[cyork]

Hi everyone,

I'm trying to install a Rheodyne 7725i Manual sample injector onto a 2nd generation Dionex Ultimate 3000 HPLC. The only issue I'm unclear of is with the position sensing switch.

With the 1st generation Ultimate 3000s, there was an installation guide and specific cable that connected to the harness of the position sensing switch, which connects to the I/O ports in the back.
Since we have the 2nd generation instrument, they went to an autosampler unit that does manual injections instead, so they don't have the specific cable with harness anymore. They have not been helpful when it comes to setting this up since they said this "should" work but it's not supported by them.

I have the I/O cable, but it doesn't have a harness - it just has all the wires labeled. I figure I need to solder two of these to the two wires of the position sensing switch, I just don't know which ones.

The information I have is:
From Rheodyne: "The position sensing switch...is a magnetic reed switch actuated by a magnet sealed inside the shaft. The switch stays closed in the INJECT position. The switch is rated for 100V at 200 mA." (http://www.inacom.nl/uploads/8/8/0/6/88 ... jector.pdf)

From dionex: The cable pairs are analog LOW/Analog HIGH, Digital Input/Digital GND, and Digital Out (GND)/Digital Output.
(http://www.dionex.com/en-us/webdocs/468 ... 9-1151.pdf) pg 51, this is from their UCI but I presume it is the same I/O switch. The switch ratings are in the document.

I should just hook it up to Digital Out(GND)/Digital Output, correct? The voltage/amperage ratings seem to match up. Am I overthinking this? Anything I'm missing?

[chemstation]

IMHO

Digital outputs seem to be for driving relays (Page 8 ), so connecting it to the
reed switch will 1) burn out the reed switch which is only rated to 200mA, where as the current coming out of the box is 500mA 2) do nothing

also on page 8, 2.4.2 Digital Inputs

In this way, they can be used to inform Chromeleon about external events, such as the injection of a sample

also on page 52, 8.3 Digital Inputs, for the 9-pin D-Sub female connector, they describe a contact closure relay, which is what a Reed Switch is.
plus it runs at +5Volts which the reed switch can easily handle.

but then again on page 34

With controlled chromatographic systems, the autosampler communicates
the time of injection to Chromeleon via an RS-232 cable. This is not
possible for non-controlled injection units. In this case, the Remote Inject
driver is required to communicate the time of injection from the
autosampler or a manual injection unit to Chromeleon and thus, to
synchronize the start of data acquisition with the injection.

[cyork]

Thanks for your input. I looked further and found that the documentation for the I/O ports for the specific LC autosampler unit I am hooking up to is slightly more informative.

It labels each of the pinouts, and says "COM is the common contact for NO and NC (all specific relay pins.) If the relay is not activated or if the autosampler is turned off, the connection is between COM and NC. If the relay is activated, teh connection is between COM and NO." Based on that, I need to go with COM and NO, which is the Digital Output/Ground I referenced in the OP.

On the manual injection valve end, it's just two unmarked wires. Would it matter which of the two cables I hook up to which? I'm just closing the relay, so it shouldn't matter, right?

[chemstation]

IMHO

Some Instruments work off of a pulse of signal, because the manual injector
will go from NO when loading to closed, until you inject the next sample.

IMHO, I would first measure the voltage from the Dionex and make sure it isn't 100Volts but 5 volts, and then test to see if creating a brief contact will start the software and acquire data. I wouldn't connect things first without proving to yourself that you understand the signalling mechanisms on each unit.

If pulse signalling works, I would suggest you chase this avenue, as I can fore see someone clicking on run before switching the manual injector to the load position and the system starts and all the retention times and solvent gradients are out.