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ALFA 6 Weft Feeder Specifications
Quella che segue è la specifica finale
generata da PRECMA S.r.l. dell'alimentatore di telaio ALFA 6, la cui
elettronica è stata sviluppata interamente da PRECMA S.r.l. per
conto della SAVI S.p.A.
This is the PRECMA S.r.l. specifications for ALFA 6 prototypes, made for SAVI S.p.A.
The feeder electronic is composed of four printed circuit boards including some hibrid circuits and three microcontrollers:
The intelligent control sistem has been developed using the "PRECMA Pick Simulator for Alfa6". Special Feeder Connections SpecificationsOne power switching hibrid circuit (12V; 5V)
SYNC signal specifications
ALFA 6 is a special weft feeder for very long weaving machines.
ALFA 6 must wind up the correct yarn length before the waving
machine pick start.
Two ALFA 6 run on the same weaving machine at the same time, and the weaving machine gets the yarn one pick from one of them and one pick from the other (alternative). It is also possible to use three ALFA 6 at the same time, if a very high precision in winding is required.
When it is running, ALFA 6 winds up the correct yarn length every
"Feeder Cycle", that can correspond to two or three weaving machine
revolutions, depending from the SYNC signal.
The LOAD switch is for a particular function of ALFA 6: if you want the feeder to wind up the yarn every time you turn ON the ON/OFF switch (LOAD function), the LOAD switch must be positioned UP. If you don't want that, the LOAD switch must be positioned DOWN.
You may want to set the LOAD function "ON" on the feeder from which
the weaving machine gets the first pick when it starts, and you may not
want it on the other feeders.
The READY signal indicates to the weaving machine that it is possible to get yarn from the feeder.
Note that READY is OFF (= Low = 0V open collector PNP) when the feeder is winding up the yarn, and is ON (= High = 12V I out Max = 10mA) when the winding ends. As the weaving machine must not activate the rear brake until the end of the feeder winding, it can use the READY signal to prevent it.
On the rear side of ALFA 6 there are:
One Amp-Latch 10 pin connectorThe amp-latch connector is used to connect the IA6 device to ALFA 6 when the operator wants to change or control the settings. IA6 device powers up itself when connected.
The green terminal connector must be connected to the weaving machine, and it is the optically isolated input line for the synchronisation signal (SYNC): see "SYNC signal specifications" section.
The green terminal connector brings also the ERROR signal (pin 2 and
It is possible to adjust the feeder winding parameters using a special device called "IA6", that can be connected to ALFA 6 and shows the settings on the LCD display.
IA6 device must be unplugged from ALFA 6 after parameter setting. ALFA 6 may not work correctly if IA6 is plugged during normal weaving operation.
Settings can be changed using the "UP" and "DOWN" keys on the front panel of IA6. IA6 doesn't works if it is not connected to ALFA 6.
With the "SELECT" key it is possible to choose from various functions:
Brake Power (Read/Write)
Single Run (Command)
Feeder Speed (Read)
Wound Length (Read)
Winding Time (Read/Write)
Error Detect (Read/Write)
This function is used to set the length of the yarn that the feeder will wind up every cycle.
The LCD display shows alternatively "Length To Wind" and the set value. It is possible to change the set value using the UP and DOWN keys. Min. value is 600cm, Max value is 1220cm.
If you try to set a value over the range, a "Comm Error" occurs.
This function is used to set the power of the front yarn brake.
The LCD display shows alternatively "Set Brake Power" and the set
value. It is possible to change the set value using the UP and DOWN
keys. Min. value is "25% Max", Max value is "100% Max", default value
"50% Max". Set lower or higher only if it is really necessary.
This function can be used to try a feeder winding cycle; it is the same as the LOAD function, but you don't need to use the ON/OFF switch and it doesn't use the front yarn brake. If the ON/OFF switch is in the position OFF, this function doesn't work.
The LCD display shows alternatively "Single Run" and "Up Key To
Start"; if you press the UP key and the ON/OFF switch is in the
ON the feeder starts a winding cycle. DOWN key is not used.
This function reads the feeder number of winding cycles per minute (cycles/min.), that may correspond to the waving machine speed (rpm) divided by the number of feeders connected. For example, if you have a 70rpm waving machine with 2 feeders connected 1:1, the feeder speed is 70/2 = 35 cycles/min.
The LCD display shows alternatively "Feeder Speed" and the read
value; UP and DOWN keys are not used. If you try to read that value
immediately after a power on, and before starting weaving, a "Comm
This function reads the length of the yarn that the feeder has wound
up during the last feeder cycle up to that moment. The LCD display
alternatively "Feeder Speed" and "Up Key To Read"; DOWN key is not
If you press the UP key you will see on the display the wound yarn
length in that moment. The wound yarn length value is cleared at the
beginning of each feeder cycle.
This function is used to set the winding cycle time.
The LCD display shows alternatively "Winding Time" and the set value. It is possible to change the set value using the UP and DOWN keys. Possible values are SHORT, MEDIUM and LONG. Winding length precision is max with the LONG value set, but the feeder will need more time to wind up the correct yarn length.
SHORT winding time is useful with high weaving machine speed (70-80 rpm) working with only two ALFA 6 at the same time.Error Detect
This function can be used to signal winding errors to the weaving machine, using the ERROR line (see "ERROR Signal Specifications" section).
It is possible to change the settings (DISABLED, MIN, MEDIUM, MAX) using IA6:
MIN signals errors -1 step +2 step
The SYNC signal must correspond to the diagram (ON = 270° = from 90° to 360°) when working with two ALFA 6. When working with three ALFA 6, SYNC signal will stay OFF for 360° more than in the diagram each winding cycle.
The green terminal connector on the rear side of ALFA 6 must be connected to the weaving machine, and it is the optically isolated input line for the synchronisation signal (SYNC):
Pin 1 (left) = 0V = GNDSYNC = ON = `1' signal correspond to "Circular Front Yarn Brake Open"
SYNC= OFF = `0' signal correspond to "Circular Front Yarn Brake Closed"
The waving machine must supply the SYNC voltage and current as indicated in diagram.Floating yes (optocoupler)
Note that the "Feeder Winding" time may result different (longer or shorter) than in diagram (fig. 5); please refer to the section "Winding Time Limits" for accurately timing the Weaving Machine Cycle.
With shorter "Feeder Winding" time there may be no problems, but with longer "Feeder Winding" time the weaving machine must take care not to activate the yarn rear brake until the end of feeder winding, that can occur even in the first part of the "Pick Time".
The READY signal can be used from the waving machine to know when it is possible to brake the yarn with the rear brake. The weaving machine must not activate the rear brake until the end of feeder winding.
ERROR output contact close when a feeders winding error is detected.
Pin 2 = Contact (relay output contact)Data for ERROR output
Floating yes (relay)
1000 VAA special SAVI 1000VA power supply with external bleeder dissipation must be used for max three ALFA 6 at the same time.