IN770AIR00XO000 Gateway BACnet Device Instance Question
I am working on a project that will be using a Samsung VRF system for it's HVAC needs and I am tasked with integrating this new system in to the existing BMS network. I would like to suggest this gateway instead of the Samsung MIM-B17BUN gateway that is currently proposed. The reason being is that the Samsung gateway does not allow for changing the BACnet device instance of the discovered units (they use a weird setup for setting up the device instances), which is not conducive to the existing device instancing standard.
Does this particular Intesis gateway allow for renumbering the BACnet device instance of the mapped Samsung units? For example, could I change the gateway instanced as Device 101, the outdoor unit as Device 102, Indoor FCU #1 as Device 103, etc. instead of some other numbering scheme so as to keep with the established device numbering standards I am working with?
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Hi Justin,
Indeed you can. Per default, the Intesis gateway will be set to have fixed instance numbering but in the configuration tab, you can simply change this to "custom" which will allow you to set custom instance numbers in the signals configuration tab. (Signal configuration being the link between BACnet and the AC system of course)
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I might've made a mistake here. You meant a device instance number for the entire unit right?
I was talking about the instance number of the objects associated with the device. The devices themselves (IDU, ODU) will not have a BACnet instance number associated with them since they will be on the Samsung network. They will of course have an ID on the Samsung network but this is not the same as the BACnet number.
Sorry for the confusion.
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I was referring to the whole unit for BACnet instance numbering.
With that, is it then a case where I can "map" the points from a particular Samsung unit (for example, from the first FCU configured for the first MCU associated to the first ODU) so that I can differentiate it from another unit of the system (for example, the second FCU configured for the first MCU associated with the first ODU)? Kind of like virtual device mapping - the example I could use is when I'm mapping Modbus devices to BACnet virtual devices, and the Modbus registers and coils then are mapped to the BACnet virtual device's virtual points. The BACnet BMS frontend software then references the BACnet virtual devices and points to the gateway, and the gateway then works with the other side of gateway with the BACnet side being none the wiser.
Sorry this is long-winded.
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Okay, yeah I see your point. I had an internal discussion with people from our Spain office where these devices and their firmware are developed and they actually mentioned that they are aware of this need/requirement from some customers so they are actually looking at implementing the functionality you are talking about.
Future releases of MAPS should include this but I have not gotten a timeframe yet.
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Good to know.
I think I understand how it works with the current MAPS setup - the gateway is the only "BACnet device" and everything data wise from the Samsung side goes to "one BACnet device" (the gateway) and how the IDU/ODU are addressed changes the fixed point instance but uses the gateway Device Instance for all of the points (assuming not using the Custom setting for the BACnet Instances).
For example, if the gateway is set with a BACnet device instance of 100, the first FCU with an address of 1 would have a fixed object instance of Analog Input 101 for Room Temperature, and FCU with an address of 2 would have a fixed object instance of Analog Input 201 for Room Temperature (if I'm understanding the manual correctly). I would then have the BACnet BMS frontend then look for 100:AI-101 and 100:AI-201 to read the Room Temperature values for those units (assuming I kept the BACnet Instances set to Fixed). Is that correct?
If that's the case, I would still be able to use this with the current MAPS configuration.
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Yes exactly, that's how I understand it as well. That's why you can have the same object instance number on the same device given that those two objects don't share the same type.
So you can have an analog input on 101 and a binary input on 101 for example but not two analog inputs on 101.
Even if you set it to custom as long as you follow the same principle it would work the same way.
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One other question: do Mode Control Units count against the Indoor Unit Count for the gateway license?
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It's not impossible that it does count towards the unit but if you have the article number on the Mode control unit I can see if I can find a definitive answer.
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What's been selected are the following models of MCUs:
- MCU-S6NEK2N
- MCU-S4NEK2N
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This turns out to be a bit tricky for us to say.
The Intesis is connected to the ODU and the ODU is connected to the IDUs and possibly MCUs. Whatever information we get from the ODU is what the Intesis will use. So it comes down to how the MCUs are interpreted as in the ODU. If they are interpreted as IDUs then they will count towards the limit most likely.
It's not impossible that this comes down to a setting in the ODU as well so I think a Samsung technician/installer would have a better understanding of how the MCUs are "handled" within the ODU.
If you decide to contact Samsung and you get a good comment on this topic we would be very interested in knowing the outcome if you feel like posting it here after.
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