Native single chip multi-port serial cards in the real world - useful?

[Jon Arnett]

Hello,

I'd like to introduce myself first as a Senior Product manager at StarTech.com, and let you know this is in no way advertising for the company; just want you to know my background before I ask a couple of questions.

We're looking at launching some new serial card products, and I figured who better to talk to than people that actual program serial control and monitoring. I've read several threads on here where people mention applications using 4+ serial ports that cause cpu levels to spike and impede performance. I'm wondering if anyone has tried any single chip serial cards on these types of applications, and how they actually work in the real world?

The cards our engineers have developed are both PCI Express cards, using single chip architecture instead of a bridge chip design like everything else out there. In their bench testing, we're seeing as good as a 48% reduction in cpu loads on the 4 and 8 port cards (RS-232). I'm wondering how actual developers use these sorts of cards though, as we're certainly open to making changes, custom driver configurations, etc. if that's what the market wants.

So, hopefully I don't flamed for being from a product company and posting here, but I would like some honest feedback on how useful these types of cards would be in your fields, and which applications you use them for? Right now, we're looking at Windows, Linux and Mac support, so hopefully that covers what everyone would need, but let me know if not.

Thanks in advance for the space, as well as your comments and insight.

[crelf]

QUOTE (Jon Arnett @ Feb 5 2009, 11:25 AM)

I'm wondering if anyone has tried any single chip serial cards on these types of applications, and how they actually work in the real world?

We used an ehterlite serial port concentrator from digikey a few years ago, and purchased a quad processor PC to control it expecting lots of CPU usage. We were pleasantly surprised with how little CPU was used, even when adressing 128 ports quasi-simultaneously.

QUOTE (Jon Arnett @ Feb 5 2009, 11:25 AM)

...we're certainly open to making changes, custom driver configurations, etc. if that's what the market wants.

If you make sure that your hardware works seemlessly with NI-VISA, then I'm happy. If I need to install anything extra, then that's (albeit a small) risk that might push me more toward a competitor of yours.

QUOTE (Jon Arnett @ Feb 5 2009, 11:25 AM)

So, hopefully I don't flamed for being from a product company and posting here, but I would like some honest feedback...

Not at all - I'm glad you came to us for the feedback. Hopefully we can help you design products that we'd want to buy That said, I think you posted in the wrong forum area, so I'm moving this thread to somewhere more appropriate.

QUOTE (Jon Arnett @ Feb 5 2009, 11:25 AM)

Right now, we're looking at Windows, Linux and Mac support...

I couldn't care less about anything other than Windows, but, as I wrote above, as long as it's compatible with NI-VISA then you should be good on all platforms that it supports.

[Jon Arnett]

Thanks for the response Crelf, I had a look at the concentrator, and I noticed the 8 port version is around $907 from their site. I had a couple of questions on a product like that.

1) For your project, was it required to control over ethernet, and did you lose any of the serial functionality you needed because of the tcp/ip connection?

2) If you were integrating something (again focusing on only 8 ports here), would the pricepoint be much of an issue for you? Our 8 port card would retail somewhere around $200 instead of $900, and give raw serial control.

As for NI-VISA, compliance is no issue, so sounds like it would work well. At this point, the card can run 8 serial ports simultaneously on a single core 2 Ghz chip without maxing it out, which is why I was wondering how much of an issue cpu usage actually was for you.

On more broad terms, are there any specific products that the industry is craving right now, or any huge complaints on products you use from other companies like Digi that we could improve upon for you?

[crelf]

QUOTE (Jon Arnett @ Feb 6 2009, 04:06 PM)

For your project, was it required to control over ethernet, and did you lose any of the serial functionality you needed because of the tcp/ip connection?

Maybe I sent you a link to the wrong product, but the concentrator we used was a PCI card, so no issues there. I don't mind using ethernet-based technology, but only if I needed to. If the systems are distributed, then ethernet is viable, but if they're not then the disconnectivity (is that a word?) and security can make me nervous.

QUOTE (Jon Arnett @ Feb 6 2009, 04:06 PM)

If you were integrating something (again focusing on only 8 ports here), would the pricepoint be much of an issue for you? Our 8 port card would retail somewhere around $200 instead of $900, and give raw serial control.

It would be crazy for me to say that price wasn't an issue, but I'm much more interested in a product that works first time, every time, out of the box. If your product is prooven, and works with NI-VISA, then sure, price would become a mitigating factor.

QUOTE (Jon Arnett @ Feb 6 2009, 04:06 PM)

At this point, the card can run 8 serial ports simultaneously on a single core 2 Ghz chip without maxing it out, which is why I was wondering how much of an issue cpu usage actually was for you.

As I said in my last post, it's not - we found a product that, once we started using it, worked just fine. In fact, better than we'd expected.

QUOTE (Jon Arnett @ Feb 6 2009, 04:06 PM)

On more broad terms, are there any specific products that the industry is craving right now, or any huge complaints on products you use from other companies like Digi that we could improve upon for you?

No.

[Dan DeFriese]

In previous projects we've used 8 port USB to Serial devices from Quatech / B&B. These use 2 chips controlling 4 ports each. We've had problem with these devices hanging temporarily on the VISA - BytesAtPort() function when 2 or more separate applications attempt to use ports controlled by the same chip.

A common annoyance is having to reassign the COM port numbers manually when these devices are replaced or moved to a different port/slot.

Some driver enhancments I would like:

*Programmatic setting between RS232/422/485.

*A hardware time-tag option.

[JohnRH]

QUOTE (Dan DeFriese @ Feb 7 2009, 06:53 PM)

...

*Programmatic setting between RS232/422/485.

*A hardware time-tag option.

Fantastic suggestions. Especially the hardware time stamp!

[Jon Arnett]

QUOTE (Dan DeFriese @ Feb 7 2009, 06:53 PM)

In previous projects we've used 8 port USB to Serial devices from Quatech / B&B. These use 2 chips controlling 4 ports each. We've had problem with these devices hanging temporarily on the VISA - BytesAtPort() function when 2 or more separate applications attempt to use ports controlled by the same chip.

A common annoyance is having to reassign the COM port numbers manually when these devices are replaced or moved to a different port/slot.

Some driver enhancments I would like:

*Programmatic setting between RS232/422/485.

*A hardware time-tag option.

Interesting suggestions, a couple of questions then. Regarding the hardware time-tag, are you referring to a logging function for troubleshooting, or something different?

Obviously moving devices also gets frustrating, so if the device support com port retention and renaming, would that be helpful? For devices like this, is working with 232, 422, and 485 a must?

Thanks.

[Dan DeFriese]

QUOTE (Jon Arnett @ Feb 9 2009, 07:45 AM)

Regarding the hardware time-tag, are you referring to a logging function for troubleshooting, or something different.

Many of my projects require some sort of timing measurement (i.e. RX packet rate). Although I typically resort to placing system time-stamp on the packet upon completion of a protocol handler. As I'm sure you know... The Windows system timer is not all that accurate for this type of use.

What would be nice is to be able to get the millisecond count associated with the last byte of a given packet and use this hardware time for my stats.

QUOTE

Obviously moving devices also gets frustrating, so if the device support com port retention and renaming, would that be helpful?

Absolutely!

QUOTE

For devices like this, is working with 232, 422, and 485 a must?

My projects use 422 almost exclusively, though some 232 is used. It doesn't do me any good to save $250-300 to use your card... then turn around and buy 8 RS232/422 converters form B&B at $50 a pop.

Being able to switch between them pragmatically would be nice in a test environment that incorporates MUX/Matrix switches. In this case, we may not need to communicate with all interfaces at the same time, but my DUTs may have a mixed bag of 232/422/485.

In any event, keep in mind these are my opinions which have been distorted shaped by my experiences.

~Dan