Com'X 200 - Connection of a pulse gas meter

[sesa205726_brid]

Dear All and

I have a question for the community about the details of the connection of a pulse gas meter to a Com'X 200, in particular, the question is related to the maximum lenght of the connection cable between the device (the distance is high, greater than of 100 m).

The alternatives are two:

1. Connect directly the pulse gas meter to the input of Com'X200: in this case is important to understand what is the maximun lenght of the connection cable;

2. Connect the the pulse gas meter to Com'X200 through 4-noks devices using ZigBee communication (ZED-TIDCI-M + gateway ZibBee Modbus): in this case I would like understand how to realize this solution.

Thank you advance for your cooperation.

BR

[sesa181247_brid]

Although each case is different, I found this article which I think explains pulse cable guidelines well...

Pulse Output Cables | Continental Control Systems

I am not familiar with ZigBee devices, but one note I do have is that if you do go with a wireless solution, you should be sure that the pulse counting takes place at the wireless device that is connected to the gas meter.  Otherwise, if its just broadcasting the pulses over wireless, you might lose counts due to dropped packets.

I have worked with Obvius Modhoppers and they work well for this application, although their wireless communications isn't that great.  Schneider offers a SCADA pack for their TRIO radios that should also work.

[sesa205726_brid]

Hi Mark,

thank you for your answer.

1. Cable length:

I would like know the cable length limit in relationship to the Com'X input caracteristics, similary to others devices as Acti9 Smartlink and SIM10M (I know the cable length limit for Acti9 Smarlink, 20 mt, and for SIM10M module, 80 mt, raccomended 40 mt.).

For example, for SIM10M the limit of 40 mt is related to the following consideration:

SIM10M can support up to 80 meters but is to recommend us 40 meters.

The SIM module provides an external voltage of 2.3 V with its own internal 2.2 kOhm resistor which limits the current to 1 mA.

The digital inputs are not normal digital inputs where you apply a certain voltage. These digital inputs does only detect a closed circuit (to ground).

No voltage should be applied at the inputs at any time.

When an input is connected to ground, a small current is generated and measured by the SIM, and a pulse is recorded. The pull-up resistor is 2.47 kohm.

　

2. ZigBee solution:

the module counts the pulse number in local and sends these to the gateway ZigBee-Modbus. I think there are not problem related to temporary drop of the trasmission.

Thank you for your attention

BR

[Anonymous user]

Hello Salvatore

1) Using the Com'X 200 digital input

     You can use either the 12 VDC that the Com'X 200 provides on the same terminal than the DI,

     You can also use another power supply (up to 24 VDC) ==> Thus, depending on your cable section, you,will be able to reach a "certain" distance

I have successfully tested 200m of AWG24 cable for pulse acquisition

Don't forget it may be necessary to use an "ATEX" barrier in order to isolate the gaz meter from an electrical device and avoid explosive risk.

It is the building owner that must decide whether the area around the gaz meter is ATEX or not

(ATXE == ATmospher EXplosive)

2) Sorry, but the Zigbee SIM are no more supported by =S= because the transmission distance was not good enough.

Rgards

[sesa205726_brid]

Hi Jef,

thank you very much.

By