7 Reading meters via pulse interface. Danfoss SonoCollect 112, SonoCollect 111

7 Reading meters via pulse interface

A simple way to digitize consumption is the pulse interface.

The method of digitization consists of outputting a certain number of pulses per unit of consumption. This way gives a pulse a weighting. It is therefore possible to infer the consumption value and thus the meter reading by counting the pulses. The weighting of the pulses is meter-specific and usually noted on the meter. Example: Inscription "1000 Imp/kWh" → 1 pulse = 1 Wh, so with each pulse the energy register can be increased by 1 Wh.

Generally, this pulse interface is referred to as the S0 interface. However, this designation is to be understood only as a synonym. There are essentially 3 different realizations:

 S0 Type A according to EN 62053-31

 S0 Type B according to EN 62053-31

 Potential free contact

Physically, the types differ from each other. The real S0 interfaces according to EN 62054-31 are digital current interfaces. A pulse is represented by a current of more than 10 mA. In the idle state, the current is less than 2 mA. Type A and type B differ only in the maximum permitted voltage. Type A uses a maximum of 27

V, type B a maximum of 15 V. The specified maximum current of results in a minimum internal resistance of

1 kOhm. A minimum voltage is required depending on the implementation.

The potential-free contact is easier to implement on the encoder side (meter). This usually simply uses the transistor output of an optocoupler which is directly controlled. The internal resistance is the same as the optocoupler and no minimum voltages are required.

This device has a pulse interface which is compatible with S0 interfaces according to type A and with potential-free contact. Therefore all common meters with pulse interface can be connected.

7.1

Setup of a meter in the web front end

The setup of a meter with pulse interface is only possible manually.

First, the pulse interface must be activated. This is done in the

(see section 4.4). Three modes can be set here:

Configuration tab via the parameter S0 mode

 Disabled

 Absolute

 Relative

The most commonly used mode is Absolute . Here, the meter value is continuously incremented by its value for each pulse. Thus, the recorded measured value should always correspond to the display of the meter.

In the Relative mode, the value is also incremented, but is reset to 0 at the end of the readout period to increment again. This can be used to record the consumption per period.

After activating and setting the mode of the pulse interface, the meter can be added in the Meter tab.

The meter is first created via the Add button or the context menu. In the dialog, the Interface must be set to S0-n (n = channel number). Further data such as manufacturer code, serial number, medium or user label are optional and can be assigned. The user may refer to Table 25 for the Medium field. This ensures a uniform display across all meters. Use the Ok button to accept the entries and the meter is created in the meter list in the Meter tab.

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Figure 33 Creating a pulse meter (sample data)

A meter value must now be added to the newly created meter. This is done by right-clicking on the newly added pulse meter and selecting the Add value command from the context menu. This command opens a dialogue box for entering the parameters of the meter value.

Figure 34 Creating the meter a pulse meter (sample data)

The parameters Value and Unit should be set to the values in the meter display. The unit may differ, we recommend using basic units such as Wh as opposed to the standard unit often used for energy meters kWh .

The parameter Scale indicates the pulse value. The value entered in Value is incremented by this value during a meter pulse. The calculation of the pulse value results from the indication on the meter, here are a few examples:

 1000 Imp/kWh → 0.001 = 1e-3 with unit kWh or 1 = 1e+0 with unit Wh

 5000 Imp/kWh → 0.0002 = 2e-4 for unit kWh or 0.2 = 2e-1 for unit Wh

 200 Imp/m³ → 0.5 = 5e-1 with unit m³

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The parameters Value and Scale must be set to ensure correct metering, the other parameters are used for an easily readable data display. The user can refer to Table 26 and Table 27 for the fields Description and

Unit. This ensures a uniform display across all meters.

The measured value set up in this way is now updated by incrementing, depending on the number of pulses acquired, with each readout. For S0 meters, only one meter value can be assigned.

7.2

Troubleshooting the pulse interface

The meter does not increment

Check the technical specification of the pulse generator, especially its internal resistance or its current consumption in active/inactive state. The detection threshold is approx. 8-10 mA.

Check the polarity.

If errors could not be rectified, please contact your local Danfoss support.

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