5069-FPD: when you need one, where it goes in the rack, and the OW16 series that needs DC

A lot of Compact 5000 questions that land on my desk aren't about the controller. They're about a narrow module that never made it onto the order, or went into the wrong slot: the 5069-FPD. Rack half built, 120 VAC inputs going in next to 24 V DC sensors, and nobody's sure where the field power splits.

The 5069-FPD is a field potential distributor. It cuts the sensor/actuator power bus and starts a new, isolated one. That's the whole job. Below: when you need one, how to lay out the rack around it, the 10 A budget per bus, and the relay card that catches people buying used.

Three kinds of power, and the one the 5069-FPD actually touches

Compact 5000 modules hand power to each other through connectors on their sides. Two buses ride along those connectors, MOD (module power) and SA (sensor/actuator power). A third kind, LA (local actuator), comes in on the front of certain output modules. Mix them up and rack layout stops making sense.

 

The module itself is one slot wide, 22 mm, with a 6-pin removable terminal block (RTB) on the front: 5069-RTB6-SCREW or 5069-RTB6-SPRING. Neither comes in the box. Put the RTB on the same order line, or you find out at install time.

It also doesn't occupy a logic slot in the controller program. So if you're scrolling the I/O configuration in Studio 5000 looking for the FPD you just mounted, stop. It isn't supposed to be there.

The three cases where a 5069-FPD is required

Three conditions call for one.

AC and DC modules on one rail. An SA bus carries one kind of power, so the DC group and the AC group each get their own bus, with the FPD between them.

More than 10 A of SA current. That's the ceiling for a single bus. Add an FPD and the modules to its right draw from a fresh supply.

A Compact GuardLogix 5380 with any AC module. The safety controller takes DC only, on MOD and on SA, from an SELV/PELV source. AC can't be terminated on it, so an FPD goes between the controller and the first AC card.

The flip side: a standard CompactLogix 5380 or a 5069-AENTR takes 120/240 VAC right on its own SA terminals. Every SA module on the rail is AC and the total stays under 10 A? Then the first bus is simply AC. No FPD.

Read "every" literally, though. A 5069-OB16 doesn't draw SA at all, its outputs run on LA. It still counts as a DC-type module and has to sit on a DC SA bus. One OB16 in an otherwise all-AC rack and you need the FPD after all.

Compact GuardLogix goes further. Safety I/O and non-relay DC modules, relay DC modules, and AC modules each need a separate SA bus, so a safety rack with all three groups ends up with at least two FPDs.

Where the 5069-FPD goes in the rack

The order never changes. Controller or adapter first, then every module that runs on the first bus's kind of power. Usually that's the DC group, because the controller's SA terminals normally get 24 V DC. Then the FPD. Then everything that runs on the other kind.

MOD runs straight through the whole rail. The FPD only breaks SA.

The two mistakes from the text (top) and the example rack laid out correctly (bottom). MOD runs the whole rail, SA splits at the 5069-FPD.

Say you're laying out a 5069-L330ER for a line with mostly 120 VAC field devices and a few 24 V DC sensors. On the order: two 5069-IB16, one 5069-OB16, an older Series A 5069-OW16, four 5069-IA16 and two 5069-OA16. Controller SA gets 24 V DC, and the IB16s, OB16 and OW16 sit right after it. Then the 5069-FPD, fed 120 VAC from its own supply. IA16s and OA16s to its right, end cap on the last OA16.

What goes wrong is the shuffle afterward. Somebody slides an IA16 between two DC cards to keep a wire run short. Now it's on the 24 V DC bus, and an IA16 needs 79-264 VAC on SA. No setting fixes that. The card moves.

More than one FPD per system is allowed, and a second one is the normal way past the 10 A limit.

5069-OW16 Series A/B vs C: the relay card that cares which side of the 5069-FPD it's on

This one catches people buying used. The OW16's contacts switch 5-264 VAC or 5-125 V DC, so parking it with the AC cards feels natural. On Series A and B that's wrong. They draw 150 mA from the SA bus at 18-32 V DC, and they need DC on whatever feeds their SA. Put one to the right of an AC-fed FPD and it's outside spec. I wouldn't power it up to see what happens.

Series C changed the rule. It doesn't draw from the SA bus at all, it just passes SA along to the next module. On MOD it draws more: 225 mA per card, against 75 mA on A and B.

 

So the series letter is the first thing I read on any OW16 off a shelf. It's on the product label. The swap to watch: a Series C living on an AC bus gets replaced with an A or B from the spares cabinet. Same catalog number, same 18-pin RTB, wrong power. C in place of A or B is fine on the SA side, just add 150 mA per card to the MOD budget.

Whatever the series, keep AC and DC loads off a shared common. Outputs 0-7 use one common, 8-15 the other.

Check the series before a 5069-OW16 goes in the rack: A or B needs a DC SA bus, C has no SA draw.

10 A per SA bus: budgeting the current

Every SA bus tops out at 10 A. For the 5069-FPD that's written into the supply requirement: source limited to 10 A, at 0-32 V DC or 0-240 VAC. Size the supply for what the bus actually draws, inrush included.

 

The OA16 is what eats a budget. 4 A per card, so two of them put you at 8 A before anything else is on that bus.

Back to the rack from before. DC side: two IB16s at 200 mA each, the Series A OW16 at 150 mA, the OB16 at zero, the controller at 10 mA. That's 560 mA, nowhere near the limit. Behind the FPD, four IA16s come to 960 mA and two OA16s to 8 A, plus 25 mA for the FPD itself. About 8.99 A. Legal, but tight, and that's before inrush.

Then someone asks for a third OA16. That bus would be at 12.99 A. Put a second FPD after the second OA16, give it its own 120 VAC supply, and hang the new card there. The original AC bus stays at 8.99 A and the new one carries 4.025 A.

Wiring the 5069-FPD: the details that matter

 

Whether the 5069-FPD gets 24 V DC or 120 VAC, the supply lands on positions 1, 3 and 5 of its 6-pin RTB.

Two habits I'd keep no matter what's in the rack. Separate supplies for MOD and SA, which Rockwell recommends too: when the SA supply drops, MOD stays up and the modules keep talking to the controller while the field side is dark. One shared supply takes both down at once.

And no RIUP. Neither the module nor its RTB supports removal or insertion under power, and pulling the FPD live can interrupt MOD to other modules in the rack. Kill MOD and every SA source first.

Red flags and what to check first

 

FAQ

What does a 5069-FPD do?

It ends the SA power bus coming from its left and feeds the modules on its right from its own DC or AC supply, isolated from the first bus. MOD passes through it.

Do I need a 5069-FPD if all my I/O is AC?

Usually not on a standard 5380 or AENTR, if the bus stays under 10 A. You still need one with a Compact GuardLogix 5380 controller, or if a DC-type card like the OB16 is in the mix.

Can I put 120 VAC on the CompactLogix 5380 SA terminals?

On a standard 5380, yes, it can start an AC bus. On a Compact GuardLogix 5380, no: MOD and SA both have to be DC there.

Why doesn't the 5069-FPD show up in my I/O configuration?

It doesn't occupy a logic slot in the controller program. Nothing to add there, nothing to set.

Is a 5069-FPD the same as a 1734-FPD?

No. The 1734-FPD is the field potential distributor for POINT I/O. Similar idea, different platform, not interchangeable.

Before you order parts for a 5069 rack

If you're building or patching a Compact 5000 system, IQElectro carries CompactLogix 5380 controllers, including the 5069-L306ER, 5069-L330ER and 5069-L340ER, plus the 5069-AENTR adapter for remote racks. For DC outputs there's the 5069-OB16 and the faster 5069-OB16F. The 5069-RTB64-SCREW kit includes a 5069-RTB6-SCREW, the 6-pin RTB the 5069-FPD takes. And whoever you buy a 5069-OW16 from, check the series on its label before it goes in.