CEL-MAR ADA-7021, Руководство пользователя

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2.4.CURRENT LOOP RECEIVER
The ADA-7021 converter has passive RX receiver having low energy short circuit protection on TX+ and TX- lines.
By the correct connection of the receiver with power source I2, Current Loop receiver 0-20mA can operate as active.
The RX red LED on front panel of the converter is a signalization of NO current flow through optocoupler. This LED is ON when it is:
- not connect transmitter to receiver,
- wrong connection of transmitter to receiver,
- broken connection of transmitter to receiver.
The diagram is shown on figure below.
Fig 2. Diagram of the transmitter & receiver ADA-7021Current Loop
2.5.ISOLATION
ADA-7021 has the 3-way galvanic isolation, on the level 1kV= or 3kV=, depend on version, described in section VERSIONS .
Fig 3. Isolation structure
3.INSTALLATION
This chapter will show how, to connect ADA-7021 to Current Loop bus, FO and power supply and how to use it.
In the purpose of minimization of disruptions from environment is being recommended to:
● apply multipair type shielded cables, which shield can be connected to the earthing on one end of the cable,
● arrange signal cables in the distance not shorter than 25 cm from powering cables,
● apply cable of adequate cross-section due to voltage drops for converter powering,
● use Interference suppression filters for power supply converters that are installed within a single object.
●
not supply converter from power circuit device that generates large impulse interference such as transmitters, contactors,
3.1.ASSEMBLING
ADA-7021 enclosure is adapted to assembly on TS-35 (DIN35) rail. To install converter, should the upper part of casing hang hooks
on the rail, than push the lower part until to hearing characteristic "Click" sound.
3.2.CONNECTION TO CURRENT LOOP DEVICE
Current Loop line is connected to TX+, TX-, I1+, I1-, RX+, RX-, I2+, I2- terminals of converter as below.
5
ADA-7021
I2 -
I= 0 / 20mA
I
I2 +
RX-
Passive Receiver I2 – Current source
RX+
TX-
I= 0 / 20mA
TX+
Passive Transmitter
I1 -
I= 0 / 20mA
I
I1 +
I1 – Current source
Power Supply
10 - 30VDC
FO
Current
Loop
3-WAY ISOLATION