Contemporary-control-systems BASremote User Manual (firmware 3.1.x) Manual do Utilizador descarregar pdf (Página 26)

TD040300-0MF

When measuring current, remember the BAS Remote sinks current to ground. A 250 Ω

impedance is effectively applied between points A and B on the input. To measure

current, it must be driven into point A with respect to point B. For two-wire current

transmitters, the more positive point on the transmitter attaches to the +24 V on the BAS

Remote loop supply or it can attached to an external loop supply as long as that loop

supply has a common connection with the BAS Remote. The less positive connection

is made to point A on the input.

Care should be exercised when connecting to a three-wire current transmitter. These

are usually non-isolated devices between the power source and signal output. The BAS

Remote will sink current from its input to ground so the transmitter must source current

from a positive potential to ground. If the three-wire transmitter works in this manner, it

can be accommodated.

Four-wire transmitters usually have isolation between power supply and signal output so

their output stage can usually be treated as a two-wire transmitter.

5.6 Analog Output

Either voltage in the range of 0–10 VDC or current in the range of 0–20 mA can be

outputted by assigning analog outputs. Configure an output using a web page. Select

the appropriate range. For DC voltage, the output voltage is applied to point A with

respect to common. For DC current, the output current is sourced from point A to

common so there is no need for a loop supply. A current output can

source up to 20 mA into a resistive load not exceeding 750 Ω. Verify the

burden that a current output device will present. The BAS Remote cannot

generate enough voltage to drive loads with higher resistance.

Figure 12 — Analog Output Connections

Figure 12 illustrates connections to a three-wire damper actuator. The damper requires

a 0–10 V command signal which can easily be accomplished by the BAS Remote.

However, if a current output is desired it is possible to set the BAS Remote analog

output to 4–20 mA and install an external 500 Ω resistor that will convert the 4–20 mA

signal to 2–10 V.

1 2 ... 21 22 23 24 25 26 27 28 29 30 31 ... 77 78

Sem comentários

Contemporary-control-systems BASremote User Manual (firmware 3.1.x) Manual do Utilizador Página 26