P3-08TAS Output card voltage???

talldude42

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Join Date
May 2015
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MI
Posts
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I am having with voltage on an issue with the automation direct productivity 3000 p3-08tas output card. The out out is wired to 120v, which is the signal voltage to a solid state delay with 480v on the load side. With the the output off, On 4 of 6 outputs I get 20v on the terminals, and the other 2 I have 58v which is apparently enough to activate the relay. I swapped out the relay and same result. Another thing I can't seem I place is it I remove the the common from the relay, turn off the output I get 120v to the relay.

This is all new equipment, fresh build but I have built 6 units this exact same way and didn't have this issue.

Any ideas? Thanks for your time people.
 
https://cdn.automationdirect.com/static/specs/p308tas.pdf
The card has individual commons.

Do you have a model number of the solid state relay you are using?
It sounds like you have some leakage current on the input side of your SSR.
Here is a thread that might help you out. You might have to connect a bleeder resistor.
https://www.ia.omron.com/support/faq/answer/18/faq02155/#:~:text=Reset%20Failure%20due%20to%20Solid%2Dstate%20Relay%20Leakage%20Current%20Even,Relay%20may%20fail%20to%20reset.

Regards,
 
The relays are either the crydom A4825 or the automation direct equivalent. But the solution you guys gave sounds like is what I need. I will try and post up a pic of the set up with a wire diagram tomorrow.
 
Ok so I have attached a summed up diagram of the schematic and a couple pictures. The load side is 480v 3-phase and the input side of the relay is 110v. Where would you recommend the resistor go? How do I figure out what size resistor i need? Mostly what I am reading it refers to a capacitor specs.

The compressed folder has the pdf file of the diagram.

KIMG0399.jpg KIMG0400.jpg
 

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I'd need to know the mA value of your PLC output leakage current, the impedance of the SSR input and the minimum on-state voltage of the SSR input in order to calculate the ideal value of the required bleeder resistor, but in general, for a 120VAC input relay, a 5KΩ resistor is adequate to pull the PLC output's off-state voltage below the minimum threshold and turn the relay off without overloading the PLC output when it is in an on-state.

Since you will be applying 120VAC to the bleeder resistor when the PLC output is on, you'll need to safely dissipate the heat generated by the resistor.

A = V / R, so 120V / 5000Ω = 0.024 A

P = I2R, so W = .024 * .024 * 5000 which is 2.88 Watts

I would use a 5 Watt ceramic resistor to safely dissipate the heat.

Connect the resistor across the input terminals of the SSR, as shown in this diagram:

faq02155_1.gif
 
The PLC output leakage current is 4mA, the SSR impedance says its current regulated and minimum on state voltage is 90VAC.

For the time being as an emergency fix I connected a coiled relay to the input side of the SSR, using the coil of the relay as a resistor to pull the voltage out. the ohms of the coil on the relay used was 1.7Kohms it work.

What is the formula to find out the ideal bleeder resistor?
 
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