Ritron DATAFLOW RTU Series Guía de usuario descargar pdf (Pagina 24)

Installation/Operation

( A-18 )

21.1.2 If the output pin is to be a current sink, correctly set the hardware configuration. The pin is to be

hardware configured as an output and as a current source. The following table defines the characteristics

of the output pins set as a current sink. Attempting to drive a load less than the minimum will cause

incorrect output and possibly can damage the device.

See Figure A8, below, for an example of how to connect a current loop meter to the DATAFLOW RTU.

ATAFLOW RT

POWER OUT

ANALOG OUT

ANALOG OUT GND

INDICATOR

ATAFLOW RT

POWER OUT

ANALOG OUT

ANALOG OUT GND

EXCITATION

VOLTAGE

USING DATAFLOW RTU

AS THE EXCITATION VOLTAGE

USING AN EXTERNAL SOURCE

AS THE EXCITATION VOLTAGE

INDICATOR

21.2 The analog outputs can be programmed to have both initial and fail-safe conditions. The initial condition

forces the output to a desired state at power ON of the device. The fail-safe condition forces the output to

a desired state if an RF data link problem is detected. Refer to DATAFLOW RTU Software/Programmers

Manual for details on setting these conditions.

21.3 Meter excitation voltage may be provided by the DATAFLOW RTU using the Power Out pin of connector

J101. If the Power Out pin is used as the excitation supply make sure that the maximum current drive of

the pin is not exceeded and that your indicator will operate on a supply voltage of Vsupply-5.5Volts.

21.4 It is not recommended to use the analog output as a warning indicator. If used, it is not available to be

mapped to the corresponding analog input of the other unit; meaning that a DATAFLOW RTU having an

analog output used in this manner can have only one analog signal sent to it. NOTE: Be sure to not

exceed the load drive capability if an analog output is used for a warning indicator.

Figure A8. - Connecting a Current loop indicator to a DATAFLOW RTU analog output

PARAMETER MINIMUM MAXIMUM

OUTPUT RANGE 0 mA 20 mA

LOAD RESISTANCE (Ev-5.5)/.02 Ω

NOTE: Ev is excitation voltage

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 62 63

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Ritron DATAFLOW RTU Series Guía de usuario Pagina 24