at the top of the magnetic coupling, pull about 1 meter of the wire out of the head with one hand. Pull
up the follower about 300mm above themagnetic coupling with the other hand. Move yourhand holding
the follower quickly down so that the follower passes through the top magnetic field to the coupling
center. Following this manipulation, there are be two possibilities. By releasing and pulling the cable,
you can find out if the follower is fixed in the magnetic coupling. If the follower does not hang on the
cable but it is fixed, the follower is placed in the correct working position. If the follower hangs on the
wire after falling under the magnetic coupling, pull the follower up to the magnetic coupling center. Check
the follower position by pulling upward at a force of about 0.15 kg (Ø 20 mm rod) or 0.45 kg (Ø 38 rod).
If you cannot pull the follower, its installation has been made properly.
7.23 Dismounting the follower
When dismountingthe FS head, pull the wire by force to release the follower from the magnetic coupling.
The magnetic coupling holds the follower and the float by a magnetic coupling force (about 0.15 kg for
a Ø 20 mm rod and 0.45 kg of a Ø 38 mm). In the case of a double magnetic coupling, this force is 1.6
times greater. After this inspection, move the follower throughout the guide rod, watching the instrument
in operation. If the instrument or pointers jerk, dismantle and recheck the inside of the guide rod and
the head. If there is no common defect such as impurities in the tube (head) or looped or stranded wires,
contact the manufacturer.
7.24 Mounting the sensing head
Mount the head to theguide rod. Ensure easy access to the scale and to the electrical equipment. Set
the instrument pointers. To set a zero position when the float is at the stop pin, loosen the screw and
set the pointers as necessary. We recommend measuring the actual level. Increase the liquid level in
the tank by about 500 mm and measure the actual liquid level using a measuring rod. Loosen the
pointer screws and set the measured value decreased by about 4 mm on the scale using small and
large pointers. By shiftingthe pointers, you can set themean value, decreasing the actual measurement
error. Tighten the pointer screws and fasten the front cover.
7.25 Error correction
The magnetic coupling counteracts the float in the liquid (friction between the rod and the follower and
friction between the float and the rod), causing level measurement differences whenever the liquid level
rises or drops. Depending on the the type of loat and medium, this difference may be up to +15 mm in
the extreme positions when the movement direction is changed. After about 30 minutes (at the turbulent
level sooner) or when the float starts moving in a certain direction, this error returns to the normal
insensitivity limit (about + 8 mm). This limit is affected by the kind of measured liquid, ambient
atmosphere etc.
Since this inaccuracy repeats regularly, the error may be assessed by comparing the data measured
e. g. using a measuring rod and a specific float sensor. The measured insensivity of the instrument is
directly proportional to the output signal of the level gauge. The error may be compensated using
software or a compensation table.
8. Setting the electrical parts, service and repairs
In general:
Mount and adjust the electrical equipment depending on the type of instrument and rear board
electronics. Use one or more terminal plates. Connect the grounding cable through the crimp eyelet to
the rearplate (see the marking). Make connections according tothe wiringtable fixedtotheinstrument´s
rear cover.
8.1 Setting the L21/3-DIAL-xx.xx.xx sensor (switches only)
When setting the microswitch contacts, proceed as follows:
- Dismount the head from the connecting flange and put it on its side next to the tube neck
