2-10 volt control

[ltd]

New to group. Was looking for an answer about actuator. I have a damper motor with 3 wires, one is 24vac, one is 2-10vdc control, the other is common. What happens if I send 24vac to 2-10 vdc wire? This was recommended by an engineer. Thanks, I can offer more specifics if needed.

[ccut]

Scroll down thru Commericial Hvac and look for a post "Economiser 2-10 vdc you might find what your looking for.

[24vac]

You will blow up the actuator input circuit. The 2-10 volt DC signal has to come
from a controller. Or, if the controller output is 4-20mA, use a 500 ohm resistor to
convert 4-20mA to 2-10VDC. Which controller are you using to control the actuator?

[ltd]

Scroll down thru Commericial Hvac and look for a post "Economiser 2-10 vdc you might find what your looking for.
I posted that inquiry. Didn't get the answer I was looking for. I thought you control guys would have more expertise..

[incontrol]

If you power the control input you can probably say goodbye to the actuator. What is the purpose of the question? I assume it is not working and you are trying to get it going. Quickly strike the control wire to the DC input and check for sparks (should be none) . I have had issues with 3 wire ones and even had to put an isolation transformer on the power supply before. Try powering it up and using a 9 volt battery on it.

[ltd]

It's an Andover controller. It has a AO that would be suitable for a 2-10v signal. I have just been getting conflicting information about applying 24vac to the signal input. Looking for clarification......

[ltd]

The purpose of the question... This is a new installation where the OA damper is required to be driven open for 100 percent OA for smoke evacuation. The installation is on a county jail. The damper is part of a carrier RTU economiser W7212.

[incontrol]

You can run an alarm input to the controller and have it drive the actuator. You can hardwire a relay to suply 10V to the the air quality input on the 7212 but I am not sure if they will remain fully open if the supply temp gets too low (good time of year to check). You can hardwire a cube relay to change the signal from the controller to one you come up with. You will have to get a power supply or program the controller to always supply voltage on a spare output.

Never 24 to the control input.



http://customer.honeywell.com/techlit/pdf/63-0000s/63-2576.pdf
page 29
table 10
step 4

[24vac]

If you have a W7212 economizer logic module controlling the outside damper, then you
have to by pass it for smoke control. The W7212 will maintain a mixed air temp even if
the CO2 input is high. Check the actuator if it is 0-10 vdc input, use a relay to
disconnect the W7212 input to the actuator and drive it open with Andover analog
out. You may freeze the building....

[fms2k]

Your clarification is quite simple and has already been
posted by both "24vac" & "incontrol" - if you send 24 vac
into the 2-10 vdc signal input on a motor you will, at a
minimum, blow out the electronics in the motor and kill it.

Either the engineer didn't quite understand what was being
asked or he doesn't understand how controls work. How
unusal .....

"incontrol" has provided you with a number of possible
solutions to the application problem. If you're talking
life safety (smoke evacuation) you should probably
"hardwire" a 10 vdc control signal to the motor as sug-
gested.

Oh, this remark (below) really not what you'd want
to post in the future:

"I posted that inquiry. Didn't get the answer I was looking for.
I thought you control guys would have more expertise.."

FYI - the people that routinely answer questions in this
forum (unlike sporadic visitors like me) have a ton of ex-
pertise that you can avail yourself of.

[BSunday21]

Not to state the obvious here; but a two- position 24v. AC. actuator would probably be cheaper and easier and exactly what you want.

[crab master]

FWIW - I've put 24VAC to the 2-10 input on an actuator only and the motor drove open, but when it didn't drive back when I adjusted the 2-10 signal is when I figured out what I did. 2-10 signal wire never was hooked up to the motor, but it had two 24VAC supplies. I don't recall what actuator brand it was, but when I hooked it up correctly it worked fine, granted it wasn't hooked up incorrectly very long. Typically we use Belimo/Delta/Duradrives.

[doodah]

More fuel for the fire. How about a spring return actuator? Set a relay to kill 24V power when smoke evac is required, the damper will spring open. No need to mess with 2-10V signal

[ltd]

I like what you're saying. I came up with 3 strategies and none of them matched this engineer's, so I asked the question thinking maybe I just didn't know enough about the signal input, like would it respond as if it had a full 10vdc when it was getting 24vac? Just a question. I think sending the AO is the best way thru a N.O. relay. Thanks for advice.

[ltd]

I didn' t mean to offend anyone in this group. Only looking to clarify what seemed to be baloney from en engineer. They are " smart". If only I could have passed calculus based physics. ..FWIW it still may work passing 24v to the input, I'm just not ready to buy some new actuators at this point based on an engineers schematic that I cannot verify will not let the smoke out of new equipment. Thanks to the group for all your input.

[ccut]

More fuel for the fire. How about a spring return actuator? Set a relay to kill 24V power when smoke evac is required, the damper will spring open. No need to mess with 2-10V signal

like it

[Control Loopy]

Just to clarify and confuse even further - If you are talking about some Belimo actuators which have a 2-10v positional input, if you feed this with the 24vAC signal they will go open.

This is called the override or sometimes frost mode - check the datasheet, and the Belimo website for some really good installation and wiring documents.
You can even put a diode in the feed and get 50% if you need!

Smart stuff! - But remember you will need a relay to disconnect the 2-10vDC signal from your DDC during the override - as it will not appreciate the backfeed!

Many other such actuators have similar ideas - some have a cable link called an RM link - this can be wired to a relay contact, which when open circuited forces open or closed.

Hope this helps.

[Dallas Duster]

More fuel for the fire. How about a spring return actuator? Set a relay to kill 24V power when smoke evac is required, the damper will spring open. No need to mess with 2-10V signal

It already is a spring return actuator. I answered his question in the commercial forum but it was answered more in this forum. It`s a Belimo actuator BTW.

[s2k008]

New to group. Was looking for an answer about actuator. I have a damper motor with 3 wires, one is 24vac, one is 2-10vdc control, the other is common. What happens if I send 24vac to 2-10 vdc wire? This was recommended by an engineer. Thanks, I can offer more specifics if needed.


I havent read thoroughly through all the answers but I'll add my two cents.
Typically, at the actuator, you CAN share(tie together) the common for the 24vac and the 2-10vdc. Also, make sure you DO have a 500ohm resister across your Anolog Output.This converts the standard 4-20ma signal to a 2-10vdc signal.
Without the resistor you will get something like 14vdc constant.

[stuckagain]

I may not understand the question,but I will give you what I think you are asking.
The 24 V.A.C. common(-) wire and The 2-10 V.DC. Common (-) wire are both connected to the 24 V.A.C. (-) common connection on the actuator.(two wires on one actuator connection)
The 24 V.A.C. (+) HOT leg connects to the actuator "24 V.A.C (+) "connection
The 10V.D.C.Hot(+)leg connects to the actuator "D.C. Volts In" connection
Al together there are four wires
Two from the 24 V.A.C.transformer and Two from the A.O on the digital controller.You have to carfully test for both the A.C. and the D.C. COMMON wires .If you wire them wrong you can possibly damage something.
All of the Siemens,Johnson Honeywell and Belimo actuators,I work on ,have to be wired this way or else They will not work.
If someone E-MAils me info on how to post JPG.images I can post a simple wiring diagram and a simple diagram on how to test for the Hot and Common legs

[osiyo]

I may not understand the question,but I will give you what I think you are asking.
The 24 V.A.C. common(-) wire and The 2-10 V.DC. Common (-) wire are both connected to the 24 V.A.C. (-) common connection on the actuator.(two wires on one actuator connection)
The 24 V.A.C. (+) HOT leg connects to the actuator "24 V.A.C (+) "connection
The 10V.D.C.Hot(+)leg connects to the actuator "D.C. Volts In" connection
Al together there are four wires
Two from the 24 V.A.C.transformer and Two from the A.O on the digital controller.You have to carfully test for both the A.C. and the D.C. COMMON wires .If you wire them wrong you can possibly damage something.
All of the Siemens,Johnson Honeywell and Belimo actuators,I work on ,have to be wired this way or else They will not work.
If someone E-MAils me info on how to post JPG.images I can post a simple wiring diagram and a simple diagram on how to test for the Hot and Common legs

Depends on the controller, guy.

On some, one never ties the commons together as you indicate. That is, the analog common to the common of the power supply for the actuator.

One needs to read and follow the manufacturer's suggestions or one may end up buying new parts.

FWIW, on a couple different manufacturer's lines of controllers I've used, I've used a single signal wire (2-10 VDC) to both Honeywell and Belimo actuators, and they worked just fine. This is not to say it'll always work that way with all controllers or all actuators. As I said, best bet is to always RTFM.

[osiyo]

Geez, the answers go all over the place, don't they?

This sort of thing I've done many a time. In one of the posts I seem to remember it being mentioned you had Belimo actuators?

If that's true, then the Belimo actuators are designed on purpose to be able to accept a 24 volt supply applied to the 2-10 VDC input wire. Doing so will simply drive the actuator in the opposite direction it'd go with 0 volts on the input wire.

In fact, when our installers put in such actuators, I've taught them to use that trick to cycle the actuators full travel first one way and then the other, to ensure it'll do so without binding and will fully open or close dampers.

Typically, for smoke control on something like relief or exhaust dampers which normally modulate based on a 2-10 volt signal from a controller, but which we want to swing wide open in response to a fire/smoke alarm we do this.

Run to AO signal wire into the NC contact of a relay, with common going to the actuator input. Then 24 volts from the same power supply as powers the actuator to the NO contacts of a fire system relay, then out again to the coil of the relay we just installed. Pig tailing the hot wire also to the NO contact of the relay.

This way if the fire system relay is tripped, you break the line going back to the controller's AO terminal, and make a direct 24 volt feed to the actuator's input terminal, driving it open. Assuming a configuration of the actuator such that it shuts with 0 volts on the signal wire.

Whatever you do, you don't want to back feed 24 volts back to that controller AO. In the case of MOST DDC controllers ... you'll blow that output.

[gnomethang]

What osiyo said but note this is for Belimo! Also I thought that with the more recent Belimos they would run through a full stroke on power reinstatement for ease of checking.