PLD or PGA

[RICH535]

I am looking to create a logic circuit with no more than 20 gates. What would be better to use a PLD or PGA or something else? We are presently using a small PLC that is presenting alot of problems. Any more info would be appreciated. Thanks.

 

[CharlieGill]

I believe you will have to describe your application a bit more to determine which device is better. I haven't had to resort to a PLD or PGA yet and have found that a fast microprocessor or SBC (single board computer) can do very fast logic for most applications. Jumping from a PLC to a PGA goes over a lot of in between choices. If you can describe your problem a bit more, I'll be happy to suggest as best I can.
Charlie

 

[RICH535]

The PLC responds to 6 different inputs from various sensors with 4 outputs. We are controlling a motor's direction with a timed-out feature to avoid any overloading. Four of the inputs are limit sensors to control the motor's ON time. Two of the sensors are conditional that allow for the motor to run at all. We are running into problems where the PLC locks up, resets randomly, and is generally not robust enough for the "hostile" environment it is used in. We are looking to simplify the circuitry with logic gating to handle the inputs and appropriate drivers for the outputs.

 

[itsmoked]

This is not the correct way to remedy this. PLCs are generally robust.

You're kind of standing there wanting to change from metal furniture to wooden furniture because the metal keeps getting bent up. All the while, not noticing the elephant standing next to you.

You need to hunt down why the PLC is freaking. Whatever it is, will be far more technical to deal with in any PLD/PGA replacement.

If you can get an isolated scope,(battery powered), and someone who knows how to use it. I suspect you will find the problem immediately and some minor change or an added EMI filter somewhere will completely remedy your problem.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

PLCs are generally robust, so what makes you think a PLD is not going to have similar, or even different, problems.

For that matter, how do you even know if your PLC is programmed correctly?

TTFN

FAQ731-376

 

[waross]

Bullet proof!!
AB 700 series relays.

http://www.ab.com/industrialcontrol...lers/industrial_relays_and_timers/700-cf.html

For timing add a pneumatic timing head, 100 FPTA30

http://www.ab.com/en/epub/catalogs/12768/229240/229254/229461/3074623/3074625/tab3.html

Scroll down a page.
We had a fire near a panel that melted some of the casting metal conduit hubs off the side of the panel.Some of these relays survived inside the panel.
Pneumatic timing is quite tolerant of electrical noise.

Bill
--------------------
"Why not the best?"
Jimmy Carter