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Thread: The low down on ALC?

  1. #41
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    Something interesting

    I was tasked with wiring up relays and safety devices as a training exercise.

    Naturally, as I was working with 24v, I wired all of the DIs for status with 24v. The controller in question is a ZN551
    This was apparently a big no-no.

    I was a bit confused. My manager (who is quite a veteran and impressively knowledgeable about ALC) said that would destroy the DI terminals. He said the DIs can only accept a return of their 0-5v output, or thermistor, or dry contact. And then one of the DIs can be set to accept AI.

    The ZN551 looked a bit dated to me, so I said "oh...uh...surely the newer controllers have fixed that...?" As Siemens stuff could pretty much accept anything - voltage, current, 1k 375 platinum RTD, 375 nickel RTD, 385 alpha, 10k type II thermistory, 100k thermistor, dry contacts, 24v, etc.
    And he said no, it's still the same.

    That's a bit curious to me. Not only do the DIs seem pretty limited in versatility, but they also use 0-5 volts?

  2. #42
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    The ZN line is pretty old and does have a lot of restrictions, and it’s a very low price. The Optiflex platform that can do all that stuff is much more money.

  3. #43
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    Quote Originally Posted by stomachbuzz View Post
    Something interesting

    That's a bit curious to me. Not only do the DIs seem pretty limited in versatility, but they also use 0-5 volts?
    In my experience this is pretty normal. I can't really think of a DDC controller i've worked with that takes 24v on a DI terminal. Certainly seen it on variable speed drives and PLCs though.

    As far as input types being limited, you will see that on older hardware but it seems there is a push for 'one-size-fits-all' universal inputs on modern stuff.

  4. #44
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    one can use 0-5v on inputs 1 and 2
    you can use any thermistor if you specify the type in the program or change it in WebCTRL after the fact.

  5. #45
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    Quote Originally Posted by MaxBurn View Post
    The ZN line is pretty old and does have a lot of restrictions, and it’s a very low price. The Optiflex platform that can do all that stuff is much more money.
    Yes, it seems that way. Still getting a feel for what's what, but the ZN551 is obviously a terminal device controller.
    The superficial specs [as I barely know them] seem to be a bit odd, but I guess if it works...

    Quote Originally Posted by Milkman Spawn View Post
    In my experience this is pretty normal. I can't really think of a DDC controller i've worked with that takes 24v on a DI terminal. Certainly seen it on variable speed drives and PLCs though.

    As far as input types being limited, you will see that on older hardware but it seems there is a push for 'one-size-fits-all' universal inputs on modern stuff.
    I obviously cannot comment for most vendors, but with my time at Siemens, I never saw anything 0-5v. All signals were either 0-10v or 4-20mA. Occasionally you would get the oddball 2-10v device, but that's as unique as it got. Some Yaskawas were setup to accept 0-10.5v signal to correspond with a 10k potentiometer.

    I had experience with Siemens devices, ABB, Danfoss, Yaskawa, Belimo, Bray, Greenheck, Daikin, and a few others.

    As far as 24v on the DI terminal, all of Siemens stuff accepts it. From the high level controllers all the way down to the field device controllers still bumpin around from the early 90s.
    While learning Siemens stuff, it was just a simple fact. It just made sense, everything else is 24v, naturally the DI would accept it.
    Now working with ALC stuff, now I'm like "wait...I can't put 24v on that terminal....?"

    As a result, I have to use twice as many relays, or every relay has to be a double pole. One pole to pass the 24v and the other to pass the 5v DI signal back to the controller.

    Additionally, on the Siemens stuff, it didn't matter where the signal was coming from. You could do a complete loop, with the Siemens panel outputting a small amount of current, a 'dry contact'.
    Then you could also just land 24v from wherever onto the DI terminal, and the terminal was internally bonded on common so grounding was pretty simple.
    Kinda like a one and done thing, no thinking required.
    Quote Originally Posted by PAB View Post
    one can use 0-5v on inputs 1 and 2
    you can use any thermistor if you specify the type in the program or change it in WebCTRL after the fact.
    I'm sure I'll learn this soon enough.

    Maybe ALC just has different situations in mind. When my manager was explaining that they can only accept 0-5v, thermistors, or dry contact, I asked how often they use thermistors? He said about 97% of the time, which quite surprised me. So maybe their goals and objectives, and what they encounter regularly, or how their temp sensors are set up, is just different.


    Speaking on the Optiflex platform that is more versatile, it seems that way, and yes - MUCH more money.

    My manager got a shipment of repaired boards back from ALC. "Repaired boards...?"
    The guys at Siemens wouldn't even bother putting in warranty claims for boards that were bad out of the box, just chuck them in the trash and get another. Sending an already-in-service board out for repair would have been completely alien language.

    My manager said "well, when they cost $15k each..."

    I'm sorry, WHAT?!

    $15k???

    He said "yeah, it's a modular controller with I/Os and it's a router too. It can do a lot"
    And my jaw was still on the floor. That's enough money to buy several of Siemens' panels, decked out with all the licenses and options.

  6. #46
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    Delta is mostly 0-5v.
    Good getting exposure. It makes you more valuable.
    It is also good to frame the comparisons as 'this is different for me' and not 'this is worse than that'. Even if something really is worse than that it may alienate people you need to get help from. As a suggestion.
    You may find yourself wondering why so and so does not seem to want to answer the phone in 6 mos. Meanwhile he is thinking 'all he does is bash what I do as worse than Siemens'.
    Hmmmm....smells like numbatwo to me.

  7. Likes stomachbuzz liked this post.
  8. #47
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    ALC will repair ANYTHING they have made, just send it in and prices are reasonable. This is especially important for things they do not make anymore. You can send in a 25 year old controller and if the traces on the board are good and they have components they will repair it. Forward support for ALC hardware and software is excellent.

    No pricing on this sub forum but you are obviously looking at something like MSRP.

    ALC makes some decisions that might seem odd to a technician but if you think of the marketing/sales angles things start making sense. They have to have a very low cost module for zone applications or they don't get bid wins, BUT if they make it too powerful you start using it in too many applications and they don't sell enough more expensive S, M, and O modules. ZN can run one program and there used to be software requirements for a mandatory zone temp, setpoint, schedule blocks. So for a cooler/freezer monitor you have this useless stuff in the program to satisfy requirements. Fortunately a lot of the ZN rules got relaxed a while back, but the hardware limits are not going anywhere. We actually saw a regression in this recently; the S line used to be damn powerful, you could run ten or twenty very simple programs (like pumps/towers) in something like a SE6166 which made it ideal for some aspects of plant control. Marketing/sales got a hold of that and nerfed the S line to one program or something like two or three if you pay more. The worst part of it is the new driver restricted older modules to the new limits, breaking some applications currently in use. I still can't believe the dealer council let them get away with that with no pushback.

    Currently there are (IMO) four tiers of ALC controllers,

    1. ZN line - very old line (at least 20 years, anyone know when these were introduced?), very restrictive hardware, single zone, probably millions of them out there.
    2. OptiFlex Advanced Equipment Controller -One or two programs, low point counts, two BMS Ethernet ports to daisy chain or ring networks. Just released, brand new tier/product line.
    3. SE line - Single Equipment, higher point count things like AHU etc. Pretty old line also, many many of them out there.
    4. Optiflex single BMS ethernet port - variety of configurations and expandable IO, can run many programs, very high point counts both physical and virtual. Been out a couple years now.


    The LGR line is almost phased out now, but also many of those out there so you need to get familiar with it. Also a very powerful and flexible module with IO and integration points, previous top of the line.
    M modules are also phased out but again many out there, these were the high IO point count modules of yesterday, can run up to 99 simple programs, expanders etc.

    All of the above is only mentioning the "current" execB BACnet controllers and the newer fwex, and the upcoming gen5. There is a whole world of ALC "legacy" exec4,5,6 controllers out there still.

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