Bus connection without delays
Drastically reducing the amount of wiring required when assembling, retrofitting and networking HEUFT devices, easily integrating spatially separated components, curbing the risk of faults and malfunctions and nevertheless reliably fulfilling time-critical tasks oneself: for this we have developed our own field bus system - the HEUFT ISI an isochronous serial interface.
Long latency times are of no use to anybody during the data transmission from sensors and to actuators particularly along high-speed filling lines. For example a trigger event has to arrive in the system as directly and with as little delay as possible for a specific container tracking. The HEUFT ISI achieves this without the complex parallel wiring of the photocell responsible for this. Because it is isochronous: the corresponding information is already everywhere where it is needed at practically the same time as the trigger event.
The status of the sensor, which records the gaps between two containers on the conveyor, is queried every 500 microseconds. This means: a new value is received 2000 times per second. The triggered product has moved a maximum distance of 0.7 millimetres by then even on fast lines where 72,000 containers are filled every hour at a conveyor speed of 1.4 metres per second. This enables consistent tracking even at high transport speeds and with the smallest gaps between the individual packages.
Simple installation
Other sensors and actuators, such as jam switches, measuring bridges and rejectors, can be integrated quickly and easily with the HEUFT ISI. They no longer have to be directly wired to the corresponding device by means of innumerable single wires. In fact they are simply connected to local bus couplers which are assembled in their close proximity. From there only one single four-wire bus line leads to the central CPU. It has such a high transmission capacity that it can replace 6,000 individual signal lines. This reduces the amount of work required for installation drastically and makes oversized cable ducts, which require intensive cleaning, unnecessary at the conveyor.
Communication between the control level and the sensor / actuator level occurs dynamically via clearly addressed data packets. Consequently input signals and control commands are available everywhere where they are needed in a 0.5 millisecond cycle.
Straightforward retrofitting
Extending the range of the functions of the HEUFT systems later is possible with the HEUFT ISI without any problems and within a very short time. Anyone who wishes to ensure a fault specific rejection, i.e. remove incorrectly filled and not properly closed containers from the production flow separately to different places, no longer has to wire the additional rejector required for this laboriously to the control unit. It is just assembled at the conveyor and a bus line is simply taken over to the rejection system which already exists. The software is then adapted for clear addressing and with that the retrofit is already completed. The isochronous serial interface also ensures here that the time-critical activation of the rejector functions without delay. Therefore only those containers which really have to be sorted are touched in exactly the correct place and removed gently from the filling line.
