K-Patents PR-03 - Manual (Page 32)

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26 PR-03 instruction manual
4.2 External output unit PR-7090
The K-Patents inline refractometer can be provided with a separate current output unit to give e.g. a tem-
perature mA signal.
4.2.1 Description
The External output unit PR-7090 has the same dimensions as the four-relay unit PR-7080 (Figure 4.1).
The enclosure has IP 65 (Nema 4X) classification. To open the enclosure, loosen the screws in the four top
corners of the enclosure and lift off cover. This will give access to the output unit’s circuit card.
The cable fittings are delivered as one of the three alternatives:
US 1/2 NPT-TYPE ST-1 conduit hubs 4 pcs
European BF11/PG11 cable glands 4 pcs
M20x1.5 cable glands 4 pcs
The mA output range of the Output unit is the same as the built-in mA output of the IT-R, i.e. either
4-20 mA or 0-20 mA. The output range is chosen through the IT-R’s software, see Section 5.8.
Two monitoring LEDs on the output unit’s circuit card indicate its status: Green LED L1 is lit when the
output unit is in order. Red LED L2 is lit when correct input data are missing. Red light means that either the
connection to the IT-R is broken (no interconnecting cable, badly plugged cable or dead cable) or that there’s
a problem on either the output unit’s circuit card or the IT-R’s processor card. Under normal operation the
green LED should be lighted and the red LED should be dark.
The External output unit is connected with the IT-R with an interconnecting cable PR-8011 . The last three
numbers in the cable code indicate the cable length in meters, the shortest available cable is PR-8011-001
(1 meter; 3.3 feet) and the longest possible cable is PR-8011-100 (100 meters; 330 feet).
4.2.2 External output unit mounting and connections
Note: Seal all unused fittings with blind washers.
The External output unit PR-7090 is mounted on a wall or similar vertical surface using its four mounting
feet. Take the length of the interconnecting cable(s) PR-8011 and easy access for service into account when
choosing mounting spot for the External output unit.
Open the screws on the External output unit and lift off cover to get access to the circuit card to make the
connections. The output mA signal is connected to the terminals 42+ and 43-.
Connect the numbered leads of the interconnecting cable with the same numbers (8-14) on the serial bus A
on the circuit card. If you have a Relay unit PR-7080, the Relay unit’s interconnecting cable is connected to
the Serial bus B.
Important: If the refractometer system does not include a Relay unit PR-7080, close the circuit with a
120 Ohm closing resistor (Figure 4.10).