Please need help on I/O Module

[yeager]

Hi and thanks in advance
I need help wiring a grayhill I/O module from the parrallel port to the spindle relay.

All suggestions are welcome and appreciated.

[Al_The_Man]

Generally these boards have negative true logic, you need to have the data sheet on the particular board you have, also will the parallel port drive an opto direct? Which typically operates at above 20mA.
I would tend to use a buffer like either a 2N7000 transistor or for more than one a DS2003 driver ic.
Al.

[gar]

060112-1708 EST USA

yeager:

I have a Crydom D2410 solid-state relay 240 VAC 10 A output with 3 to 32 VDC input. With 5 VDC on the input the current is about 2.5 MA.

An Opto22 type module OAC5 (happened to be a P&B ) with nothing in series with the input pins and 5 VDC applied draws 20 MA. If mounted in a standard IO board with a series LED the current drops to 15 MA.

You need to determine the sink capability of your parallel port output. This will determine what you need to do.

.

[unterhaus]

There is no way to drive them to logic high with any parallel port newer than 1987 or so. So you'll have to pull them low, no matter how your carrier board is set up. I think for reliable operation you need to use a buffer chip, something like a 74ls04 might work.

Just looked at your picture. Those boards will allow you to use negative or positive logic. I have found that pulling the negative input to ground is much superior than trying to drive the positive terminal high. So hook the positive terminals together to 5v, and put your inputs on the low side.

gar, I had no idea those Crydoms pulled so much less current than an output module. That's good to know.

[Al_The_Man]

Originally Posted by unterhaus Just looked at your picture. Those boards will allow you to use negative or positive logic. I have found that pulling the negative input to ground is much superior than trying to drive the positive terminal high. So hook the positive terminals together to 5v, and put your inputs on the low side.

I think the Grayhill had only one flavour, not like P&B who offered several different configurations for the barrier strip in and out type of board, they used to make just the 70RCK4, which had only sink option.
They have a 3.3k pull up and a LED in series with the logic in pulled up to VCC.
Grayhill, however for their modules boast being lower than the industry standard for this type of module, they claim 11ma operating over the ind. standard of 14ma for the 5v versions.
I stand corrected, Grayhill now have several versions, my catalogues are older.
http://www.grayhill.com/Grayhill.nsf/947848defbb4d47e8625682c006b98b9/520542a7d819cb0786256847007ad7a5/$FILE/H-70-71.pdf
Al.

[gar]

060112-2023 EST USA

unterhaus:

I was surprised about the Crydom as well, but on reflection it makes sense relative to the maximum input of 32 V. When I am back at the shop I will check current at 32 V.

This relay dates to about 1972 or 1973 in our early work on pinion preload adjustment. We never used a solid-state relay for this application because the dropout time was too long. Instead we used KUP relays that would last about 6 to 12 months. But this gave the electricans something to do in an otherwise reliable system. Sometimes it is better that they have some activity like this.

.

[yeager]

Sorry, Im still not exactly sure what to do. (im a sign guy)
Do I hook the (-) side directly to the parallel port then the (+) side directly to 5v+dc. Where is the best place to find the 5v dc source?
Finally, do i run Mach3 outputs as active low?

Thanks Again--

[Al_The_Man]

If I remember you only need to hook up the 5v(-) if you are using input modules, otherwise just the logic and the 5v(+).
If I were you I would feed the board directly from one of the PC power supply 4pin leads. Red +, Black common (if used).
The software would be set to active low if that is the style of board you have.
Al.

[unterhaus]

Originally Posted by yeager Do I hook the (-) side directly to the parallel port then the (+) side directly to 5v+dc. Where is the best place to find the 5v dc source? Finally, do i run Mach3 outputs as active low?Thanks Again--

A qualified yes to all your questions. I'd pull 5v from the pc power supply, use a disk drive extension cable. You can also pull the 5v from a USB cable. At work, I have a system that was supposed to be computer run, but we never got around to it, but to run the logic, we crank up the computer to get the 5v.


Unless you have an endless supply of motherboards, I would use a breakout board. I just bought a breakout board from cnc4pc:
http://www.cnc4pc.com/Parallel_Port_Interface_Card.htm
and it looks pretty nice. For not very much money you could save your motherboard plus some headaches. If it wasn't my second breakout board in this system, I probably would have bought from Sound Logic or PMDX.

Al, you're probably right, I never thought about the second pin being for input modules. Maybe that's why I had so much trouble last time I wired one of these up :O

Without a schematic, it's not possible to tell for sure, but active low outputs sounds right for a spindle relay.

[gar]

060113-0849 EST USA

To complete my comments on the Crydom D2410.

With a 100 Watt lamp load at 120 VAC supply at room temperature (70 deg F.) the input pull-in voltage is 1.85 V and drop-out is 1.62 V. Plenty of margin relative to IR's minimum specification of 3 V. A 100 W vs 1000 W load should have no effect on the pull-in voltage.

At 32 V input the input current is about 20 MA. Reasonable for a maximum continuous excitation of the LED. Thus, the internal series resistance is about 1500 ohms and this roughly correlates with the 2.5 MA at 5 V input assuming an LED drop of 1.25 V.

.