NetBotz Dry Contact connection to Fire Alarm Panel, Generator or AC

DCIM_Support · ‎2020-07-04

This question was originally posted on DCIM Support by pzodawa on 2017-10-28

Hi,

Any advise on connecting NetBotz 570 to external equipment e.g. fire alarm panel, generator or AC dry contacts, specifically on conditions the equipment contacts must fulfill?

DCIM_Support · ‎2020-07-04

This answer was originally posted on DCIM Support by spezialist on 2017-10-28

Dear pzodawa and team,

From my own practical experience: there are no problems or special recommendations. If you mean NetBotz Dry Contact Cable - 15 ft. (NBES0304), the external equipment (e.g. fire alarm panel, generator or AC dry contacts) should simply have low-voltage dry contacts (NC or NO), that are able to switching the load max ~5V/0.5mA.

The time for the presence of dry contacts in the closed or open state must be at least >200mS. Otherwise, NetBotz device simply does not detect changes in the status of dry contacts. This is described in the following documents on the NetBotz device:

NetBotz Rack Monitor 200 - Installation and Quick Configuration Manual - on page 23;
NetBotz Rack Monitor 450/550/570 Installation and Quick Configuration Manual - on page 28;
NetBotz Rack Monitor 250 - Installation and Quick Configuration Guide - on page 30.

The active resistance of the dry contacts (excluding active resistance NetBotz Dry Contact Cable - 15 ft. (NBES0304)) should be no more than <9kOhm, so that the NetBotz device reliably determines the closed state of the dry contacts.

Similarly, the active resistance of dry contacts (excluding active resistance NetBotz Dry Contact Cable - 15 ft. (NBES0304)) must be at least >11kOhm so that the NetBotz device reliably detects the open state of the dry contacts.

This should be taken into account in special cases, when dry contacts are connected to a NetBotz device using an extension cable, for example, a structured cabling system of the building, fireproof cables for fire panels and the like.

In addition, in all cases, it is recommended to attach a ferritic bead to the external sensor cable as close to the NetBotz device as possible, for EMI suppression.

And the last recommendation for the use of extension cables for external sensors and, in particular, for using NetBotz Dry Contact Cable - 15 ft. (NBES0304). You should always try to connect NetBotz Dry Contact Cable - 15 ft. (NBES0304) directly to the sensor port of the NetBotz device, i.e.:

NetBotz (sensor port) <-- NBES0304 cable --> 3rd party extension cable / patch panel, etc. <-- dry contact in external equipment

And you should try to avoid connecting NetBotz Dry Contact Cable - 15 ft. (NBES0304) to the sensor port NetBotz device via an extension cable, i.e. like this:

NetBotz (sensor port) --> 3rd party extension cable / patch panel, etc. <-- NBES0304 cable --> dry contact in external equipment

This is due to the fact that the RJ-45 connectors of external sensors have some radio components responsible for the correct identification of the sensor in the NetBotz device. If this is not understood, then, under certain circumstances, strange problems can really appear, for example, as Sven Ortmann described in his question .

I am glad to answer your questions.

See Answer In Context

DCIM_Support · ‎2020-07-04

This answer was originally posted on DCIM Support by spezialist on 2017-10-28

Dear pzodawa and team,

From my own practical experience: there are no problems or special recommendations. If you mean NetBotz Dry Contact Cable - 15 ft. (NBES0304), the external equipment (e.g. fire alarm panel, generator or AC dry contacts) should simply have low-voltage dry contacts (NC or NO), that are able to switching the load max ~5V/0.5mA.

The time for the presence of dry contacts in the closed or open state must be at least >200mS. Otherwise, NetBotz device simply does not detect changes in the status of dry contacts. This is described in the following documents on the NetBotz device:

NetBotz Rack Monitor 200 - Installation and Quick Configuration Manual - on page 23;
NetBotz Rack Monitor 450/550/570 Installation and Quick Configuration Manual - on page 28;
NetBotz Rack Monitor 250 - Installation and Quick Configuration Guide - on page 30.

The active resistance of the dry contacts (excluding active resistance NetBotz Dry Contact Cable - 15 ft. (NBES0304)) should be no more than <9kOhm, so that the NetBotz device reliably determines the closed state of the dry contacts.

Similarly, the active resistance of dry contacts (excluding active resistance NetBotz Dry Contact Cable - 15 ft. (NBES0304)) must be at least >11kOhm so that the NetBotz device reliably detects the open state of the dry contacts.

This should be taken into account in special cases, when dry contacts are connected to a NetBotz device using an extension cable, for example, a structured cabling system of the building, fireproof cables for fire panels and the like.

In addition, in all cases, it is recommended to attach a ferritic bead to the external sensor cable as close to the NetBotz device as possible, for EMI suppression.

And the last recommendation for the use of extension cables for external sensors and, in particular, for using NetBotz Dry Contact Cable - 15 ft. (NBES0304). You should always try to connect NetBotz Dry Contact Cable - 15 ft. (NBES0304) directly to the sensor port of the NetBotz device, i.e.:

NetBotz (sensor port) <-- NBES0304 cable --> 3rd party extension cable / patch panel, etc. <-- dry contact in external equipment

And you should try to avoid connecting NetBotz Dry Contact Cable - 15 ft. (NBES0304) to the sensor port NetBotz device via an extension cable, i.e. like this:

NetBotz (sensor port) --> 3rd party extension cable / patch panel, etc. <-- NBES0304 cable --> dry contact in external equipment

This is due to the fact that the RJ-45 connectors of external sensors have some radio components responsible for the correct identification of the sensor in the NetBotz device. If this is not understood, then, under certain circumstances, strange problems can really appear, for example, as Sven Ortmann described in his question .

I am glad to answer your questions.

DCIM_Support · ‎2020-07-04

This comment was originally posted on DCIM Support by pzodawa on 2017-10-29

Dear spezialist,

You have pretty much answered my question. Thanks for the prompt response, much appreciated!

DCIM_Support · ‎2020-07-04

This comment was originally posted on DCIM Support by spezialist on 2017-10-30

I am glad to answer your questions 😀.

DCIM_Support · ‎2020-07-04

This answer was originally posted on DCIM Support by scott.sexton on 2017-11-01

Hi pzodawa

As spezialist mentioned the Netbotz dry contact cable will work perfectly. I have this setup and working to provide fire alarm panel notifications such as 'manual mode' or 'stage 2 suppression gas release.'

A MODBUS connection to the 570 would provide you much more information for your generator than dry contact. However, your facilities team may wish to use any MODBUS card to connect to their Building Management System (BMS). I have my generator using dry contact to DCE reporting on low fuel, generator running on load, common alarm and low battery charge. The MODBUS then goes to our maint team who operate and support the generator via the BMS.

DCIM_Support · ‎2020-07-04

This answer was originally posted on DCIM Support by Christopherus Laurentius on 2017-11-02

Just to add on great inputs from spezialist and scott.sexton; for dry contact, I would recommend to use a normally closed (NC) contact instead of normally open.

That way, you'll get notified in the event the cable break.

On some fire panel, as mentioned above, these panel will typically have several dry contact outputs, i.e 1st stage, 2nd stage and panel fault etc. Suggest to monitor these using individual dry contacts, to get clarity on the alarm.

If you need a large amount of dry contact input, it might be easier to use Netbotz with sealevel I/O, where you can install the sealevel terminal block kit inside a dedicated panel.

As for genset, yes, if you need more details like fuel level, output voltage, etc, those are typically via modbus.

DCIM_Support · ‎2020-07-04

This comment was originally posted on DCIM Support by spezialist on 2017-11-02

Since this topic was interesting for the community, I supplemented my answer so that it was detailed and complete.

Always happy to answer questions 😀.

DCIM_Support · ‎2020-07-04

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