Fancom 771
INSTALLER: 4. Mounting and installation
7
The speed of the transport chain/transport auger must be related to the distance of the valves to allow
the valves to be controlled at the right moment. This is achieved by generating one or more pulses per
revolution of the transport system or auger wheel (e.g. a flex auger or spiral). The computer reads these
generated pulses and processes them.
A pulse can be generated in different ways: mostly using a capacitive sensor (RPM feedback
construction). Mount the sensor in such a way that, for example, the bolts on the wheel are counted. For
connection of the pulse counters, refer to the connection diagram concerned in appendix 1.
For accurate dosing out, a minimum of one pulse per minute has to be generated. The maximum number
of pulses per second is 500. There is a digital input per circuit. For connection of the RPM feedback to
the terminals, refer to the connection diagram concerned in appendix 1.
Mount a so-called overflow protection at the end of each circuit. Feed which has not reached a valve will
be caught by the overflow. This is usually caused by a valve not opening (incorrect connection, incorrect
assignment, bad contacts, no air pressure, etc.). It is also possible that the feeder under the valve was
too full to allow a complete portion to be dosed.
An overflow could be a bucket, suspended from a pull switch. This switch makes contact when the
bucket exceeds a pre-set weight. For connection of the overflow detection, refer to the connection
diagrams concerned in appendix 1.
Connect the contact (per circuit) to the overflow input of the 771 computer.
It is also possible to detect surplus feed using a proximity switch (PROX.24F). See connection diagrams
Overflow alarm (appendix 1).
The overflow can also be connected as a so-called Overflow detection. When a programmed quantity of
feed is exceeded the computer will not give an alarm but a Warning. The computer indicates from which
valves the feed came and gives a Silent alarm. The position of the overflow (in pulses) should therefore
be entered (see section 6.2). This type of overflow detection consists of a proximity switch, PROX.1
(PROX.24A) with a programmable sensitivity and a larger hopper, possibly containing another proximity
switch, PROX.2 (without programmable sensitivity).
4.8 Connecting the pulse counters
4.9 Connecting the overflow detection
