output and timer not likeing each other

I have a Modicon B810 115v isolated triac output module tuning on an Omron H3YN-4ac100-120 timer.

When the processor turns on the output nothing happens, but when I pull timer out of the socket the light for the output comes on. When I put in an Omron MY4IN relay it works fine.

Also when I energized timer from another source (straight off control transformer) it works fine.

Any ideas why the timer wont work with this output module?

Triac off state leakage current is probably keeping the timer energized even when the output is in the off state.

But you say that the output light does not illuminate until the load is removed, so that leads me to think something is not wired correctly or the load of the timer is too great for the output (not likely).

I have no experience with either device so these are just guesses.

Paul

agree with okie. have you checked the voltage going to the timer when output is on (or supposed to be on). with and without load. you could also check amps with tongue tester. sounds like a short to me

chud said:

you could also check amps with tongue tester.

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I just have to ask. What is a "tongue tester"? When I read this all I can think of is touching the 120V and neutral to one's tongue!

I dont think it is the wiring or short circuit because the output works on a coil type relay. It also works with a different type of timer.

Thanks for the replies. Any more ideas?

milldrone said:

I just have to ask. What is a "tongue tester"? When I read this all I can think of is touching the 120V and neutral to one's tongue!

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That was exactly what i meant.lol. Here in africa we have to resort to strange methods sometimes. hehe.
Very bad typo

jcole1 said:

I dont think it is the wiring or short circuit because the output works on a coil type relay. It also works with a different type of timer.

Thanks for the replies. Any more ideas?

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I know its a stupid question. but are you using the correct pins on the timer. maybe you are going through a NC contact instead of to the coil. like i said if you could test the amps going to the coil when output is on you will see what is the cause.

ps : Dont resort to the "tongue" test method. Leave that to the trained proffesionals we have here in Africa

Its not the wiring either. When I jumper around the output contact the timer works fine. Iam using another timer at this time so its really no big deal. But this compulsive disorder I have wont let me let it go until I find an answer.

Wire the timer to a switch from a normal power source. Put your meter on peak hold ac amps an in series with the switch. Turn on the switch to find out how much current it draws. Compare that with the specs of your triac output card.

Also, I read the specification of the timer and it requires the voltage to drop to <10% (12 vac) in order to reset. If the timer does not sufficiently load the output, the voltage may never drop that low when the triac is in the off state.

Hope this helps.
Paul

OKIE,I am not at work today so I cant do amp test. The spec sheet says 1.8va power consumption in the on state and 1.0va in the off state. I cant imagine this would overload the output device.

Thanks for the reply.

Yes, but is your particular timer conforming to those specs? And does the spec describe the inrush current (if any)?

Most triac outputs on PLC cards will handle 0.5 amps continuous, but they'll flow enough current in the off state to power leds, some very small relays, and definitely fool your meter if no load is connected to pull down the voltage.

You can try wiring another load in parallel (like that relay you mentioned), or use an interposing relay to ensure the voltage present at the timer input terminals drops sufficiently.

Your B810 card can handle 2 amps per channel.

"Output status indicators are provided for each output circuit. These neon indicators will be ON when a load is connected and the output is ON or when there is no connected load"

The off current is listed as 3mA max. So, the timer consumes 0.008 amps in the off state and the output card supplies up to 0.003 amps in the off state...on paper that seems okay, but when you get the chance, try measuring the voltage at the timer terminals with the output off and ensure that it drops low enough.

Enjoy your day off!

http://v1.graybar.com/automation/ga_manuals/Hardware/800 IO/B810-008 115 VAC Output Module.pdf

Thanks Okie.

I understand more of what your saying now. I was just reading spec sheets and assumed it ok. Need to measure results and not assume.

Thanks again and I am enjoying my day off. No kids or wife home, just me and the dog. Ahhhhhhhhhhhhhhhhhhhhh

Just a thought stirring here.
Has one half of the Triac failed and it is now delivering half wave DC.
In that case it would appear to be switching OK, and depending on the loads, some may work and others may not, there may be some extra buzzing noises, and its not always straight forward to test for, mainly because the half wave DC is pulsing at the AC rate.

Gil47 said:

Just a thought stirring here.
Has one half of the Triac failed and it is now delivering half wave DC.
In that case it would appear to be switching OK, and depending on the loads, some may work and others may not, there may be some extra buzzing noises, and its not always straight forward to test for, mainly because the half wave DC is pulsing at the AC rate.

Click to expand...

Excellent outside the box thinking. I had this happen to me once on a CLX triac output card . In my particular case half of the outputs were all fried, or half fried as it were. The outputs that were connected to motor starters were still half functional (they were slow to release the starter) The outputs connected to push button indicator lamps, were glowing dimly when they should have been off.

The test was relatively easy. I have an old fashioned wiggy with a neon inicator (has to be neon). When testing the outputs that were connected to motor starters and the output was supposed to be off, one side of the neon indicator would glow. When the output was on both sides glowed.