1734 Point IO for 24VAC

TheWaterboy · Apr 22, 2015

Is there an input and output module for 5370 controllers that can use 24VAC? I see 120VAC but not 24VAC. I am replacing a PLC5 that uses this voltage and I would prefer not to interpose a relay.

the_msp · Apr 22, 2015

I don't think so. Had a project proposal last year that was 48 VAC. Asked AB rep who suggested the relays from FLEX IO, which didn't solve my problem. Oh, and this job had 1400 IO.

scott.maddox · Apr 22, 2015

With the 1734 series you can use the 1734-fpd that allows a wide range of voltages to be used for the io modules.

TheWaterboy · Apr 22, 2015

the_msp said:
Oh, and this job had 1400 IO.

Yikes, I have 22 and I was complaining

What did you wind up doing?

TheWaterboy · Apr 22, 2015

scott.maddox said:
With the 1734 series you can use the 1734-fpd that allows a wide range of voltages to be used for the io modules.

I don't think that does what I need, it breaks a common bus voltage but still doesn't allow 24vac IO in any way I can determine. Unless there was 24VAC I/O to the right of it.... which is what I cant find.

the_msp · Apr 22, 2015

Budgeted for lots of relays and 4 meters wide of cabinets to hold them all, and the point IO needed to drive the 24VDC OP relays and accept the interposed signal from the 48VAC coil relays. Not nice I know, but in the end the project didn't go ahead as the plant manager retired and his successor made the decision to wait until the old (1984) system broke again before going ahead. Expecting a call some day... 'so... that job you quoted 16 months ago, we want it done and we want it done tomorrow....'

TheWaterboy · Apr 22, 2015

That appears to be the direction I am going too.
Whats wrong with 24vac I/O anyway. Its great to prevent wiring corrosion in damp environments and along with 48vac used to be a standard in LCPs.

einnh · Apr 22, 2015

Phoenix has some pretty compact ones that might be a good fit for you if you end up going the relay route.

http://j.mp/1zNooVc

the_msp · Apr 22, 2015

The 48V ac ones I was using were circa 4mm wide for SPCO. Series Omron G2RV. No manual override, but LED indication.

The 24VDC ones were phoenix contact, again under 5mm wide with LED indication

Symbot · Apr 22, 2015

Here is what ive been using for the last few years. Hope it works for you.

*Controller, CompactLogix 5370 L3 / AB-1769-L36ERM
*Output Module, Compact, 32-Point 24vdc Source / AB-1769-OB32
*Input Module, Compact, 32-Point 24vdc Sink/Source / AB-1769-IQ32

*Disregard, i just realized you said AC*

scott.maddox · Apr 22, 2015

Use the field power distributor with a broad range of voltage inputs including 5V DC to 250V DC and/or 24V AC to 240V AC applications and I/O modules.

Above is from the rockwell website on the fpd module. Maybe im misunderstanding you but it seems like this breaks the io voltage from the module voltage and allows you to provide a separate voltage for your io instead of having to use the 24vdc power.

TheWaterboy · Apr 22, 2015

Scott.
But... there are no 24vac I/O modules that would benefit from this module. There might potentially be an esoteric module somewhere in the catalog that uses 24vac as its power supply, and that would be the purpose of the FPD, but none of the 1734 point IO is available to deal with 24vac.

scott.maddox · Apr 22, 2015

I could be wrong but i thought that for instance the ob8 module has no fixed voltage, it simply uses whatever voltage you feed it from the base module or fpd. Typically it uses 24vdc because that is what you feed the aent or ep24. Thats why there is one source of power for the io and the module. The fpd allows you to power the aent with 24vdc but breaks the io power to allow you to supply the range of voltage listed to the io. I have not used thismodule for this so you may want to check with your rep but thats how i understand it to work.

rdrast · Apr 23, 2015

scott.maddox said:
I could be wrong but i thought that for instance the ob8 module has no fixed voltage, it simply uses whatever voltage you feed it from the base module or fpd. Typically it uses 24vdc because that is what you feed the aent or ep24. Thats why there is one source of power for the io and the module. The fpd allows you to power the aent with 24vdc but breaks the io power to allow you to supply the range of voltage listed to the io. I have not used thismodule for this so you may want to check with your rep but thats how i understand it to work.

That is completely wrong. It is a 24VDC transistor output.

TheWaterboy · Apr 23, 2015

Thanks for the confirm rdrast, Scott had me thinking I hadn't read it right and I was gaining hope. Now I'm back to normal.

And I appreciate the input Scott. I only wish you were right.

1734 Point IO for 24VAC

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