Burkert Type 8793 - Manual (Page 48)

48
Installation
Type 8792, 8793
english
12.4.3. Connection and start-up via a 4 – 20 mA path sensor (for
Type 8793 remote model only)
When a 4 – 20 mA path sensor is connected, the process controller Type 8793 can be used as a positioner
(position controller) only, as the process actual value input is used as input for the path sensor.
In principle, any path sensor with a 4 – 20 mA output can be connected which has an adequate resolution of the
path signal.
Good control properties are obtained if the resolution of the path sensor allows at least 1000 measuring steps
over the path to be measured.
Example: Path sensor with 150 mm measurement range
Of which used measurement range (= stroke) 100 mm
Required minimum resolution of the sensor:
100 mm
= 0.1 mm
1000 Steps
WARNING!
Risk.of.injury.from.improper.start-up!
• Start-up may be carried out by authorised technicians only and with the appropriate tools!
Risk.of.injury.from.unintentional.activation.of.the.system.and.an.uncontrolled.restart!
• Secure system from unintentional activation.
• Following assembly, ensure a controlled restart.
Connect 4 – 20 mA path sensor to the terminals 1 - 4 of the process controller Type 8793 remote model.
(see chapter “Table 21: Terminal assignments of the process actual value input”, page 60 /
Internal supply of the path sensor by Type 8793:
→ Connection according to input type “4 ... 20 mA - internally supplied”
Separate supply of the path sensor:
→ Connection according to input type “4 ... 20 mA - externally supplied”.
→
Attach remote sensor on the actuator.
The correct procedure is described in the instructions for the path sensor.
→
Connect compressed air to the Type 8793.
→
Connect Type 8793 pneumatically to the actuator
→
Switch on Type 8793 operating voltage.
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To obtain the best possible control precision, adjust the path sensor so that path to be measured corresponds
to the signal range 4 – 20 mA (only if the path sensor includes this function).
→
In the ADD.FUNCTION menu activate the POS.SENSOR function. Then select POS.SENSOR in the main
menu and set ANALOG.
(see chapter “26.2.19. POS.SENSOR – Setting interface remote path sensor”, page 142.
→
Run the X.TUNE function.