K-Patents PR-03 - Manual (Page 24)

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18 PR-03 instruction manual
4.1.1.1 Relay unit PR-7080
The Relay unit PR-7080 contains 4 relays from left to right: Relay A, relay B, relay C and relay D. There is
a yellow LED above each relay. If the LED is lighted, the corresponding relay is ON and the output contact
is closed. There is also one green and one red indicator led to inform on system status. After startup the red
led is lighted only when the relay unit has problem.
The Relay unit PR-7080 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).
4.1.1.2 Relay unit -WR
The Relay Unit -WR contains 2 relays from left to right: Relay A and Relay B. There is a yellow LED
above each relay. If the LED is lighted, the corresponding relay is ON and the output contact is closed.
4.1.2 Prism wash system description
Deposit build-up on the prism surface disturbs the measurement. Look out for an abnormally high concen-
tration reading
, low slope value or an upward CONC drift.
In most applications the prism will keep clean due to the self-cleaning effect. If coating occurs, check the
following:
− Sufficient flow velocity, see Section 2.2.2, “Check list for pipe mounting (PR-03-A, PR-03-D, PR-03-M)”.
− A temperature difference between process fluid and sensor probe may cause coating. This may happen
with small flows if the thermal insulation is inadequate. In some cases it helps to insulate also the clamp
connector.
In case of a coating problem, the preferred solution is to try to increase the flow velocity, e.g. by installing
a pipe portion with smaller diameter. Installing a wash nozzle can be considered, if increasing the velocity
does not provide a solution (Section 4.1.4).
Three alternative media can be used for prism wash: steam, water, high pressure water. Only external relays
(accessory units) can be configured to control the prism wash cycle, see Section 5.9 “Configuring automatic
prism wash”.
4.1.3 Relay unit mounting and connections
Note: When mounting a separate relay unit, seal all unused fittings with blind washers.
4.1.3.1 Mounting and connecting Relay unit PR-7080
The four-relay Relay unit PR-7080 is mounted on a wall or similar vertical surface using its four mounting
feet. Take the length of the interconnecting cable PR-8011 and easy access for service into account when
choosing mounting spot for the Relay unit.
Open the screws on the Relay unit and lift off cover to get access to the relay card to make the connections.
The relay contacts go to the connector strip (Figure 4.2) on the relay unit card.