Benezan Electronics
Hard- and software development
Installation ManualBreakout Board
Nicolas Benezan, Stauffenbergstr. 26, 72108 Rottenburg
Phone: +49 (0)7457/946365 0 benezan-electronics.de
Page
Breakout8-Installation_Englisch
(Vereinigte Staaten).docxdocx 22.09.2020
Relay outputs
The relay outputs 1 and 2 can be used to switch 230V consumers such as spindle motor, coolant pump or chip
extractor. The current consumption must not exceed 8A per relay, otherwise the load must be switched with an
external contactor.
Instead of 230V~, 24V consumers can also be switched, such as contactors or pneumatic valves. However,
24V and 230V must not be used together, as in this case the required insulation distances cannot be maintained.
The voltage source is connected to pins 1 and 2 of X4, the loads to pins 3+4 and 5+6.
If potential-free contacts are required instead, e.g. for the digital inputs of a frequency converter, relay 1 can
be used as a make contact between pin 1 and 3, relay 2 between pin 2 and 6. Here, too, it should be noted that
mixed operation with 230V is not permitted because of the insulation distance.
Relay 1 (left) can be switched either via LPT pin 1 or the PWM function. Relay 2 (right) is controlled by pin
14. The switching status of both relays is indicated by one yellow LED each. The relays switch on at high signal
on the LPT port. Attention, if the watchdog is deactivated, the relays may switch on uncontrolled at undefined
levels.
Reference switch inputs
Up to 4 switches or inductive sensors can be connected. If the 4th axis is not used or does not require a reference
switch, a tool length sensor can be connected here, for example.
Mechanical switches or inductive proximity switches of the PNP type can be used. If proximity switches are
to be used, JP3 must be set to 24V (top) and the board must be powered with 24V. The sensors should be
connected as follows: brown (+24V) to terminal 1, 3, 5 or 7, blue to the ground connection of the power supply,
black (signal) to terminal 2, 4, 6 or 8.
The inputs are inverting, i.e. the corresponding LPT pin is high when the switch input is open (low) and low
when the switch input is closed (high). Normally closed or normally open contacts can be used if the polarity is
selected accordingly in the PC software.
The switch inputs have a Schmitt trigger function and are interference suppressed with a low-pass filter, so
that there is usually no need to fear interference even with unshielded cables. The inputs are overvoltage tolerant
up to +80V.
Please note that the switch inputs are not suitable for fast signals (>1kHz) with 5V level, for example TTL
encoder signals. However, it is possible to use an inductive or Hall sensor for spindle index (speed measurement
or for thread cutting) if the sensor is operated with 12 or 24V.
Emergency stop
The breakout board has several independent functions that are used to stop the machine in case of problems:
1. An emergency stop button (mushroom/panic button) must be connected to terminals X2.5 and X2.6. If
the contact is opened, relays 1 and 2 are forcibly switched off. A push-button emergency stop is
indicated by the right LED (red, LED1). Additionally an emergency stop is reported to the PC (LPT pin
11)
2. If the status output of one or more output stages reports an error or if this line is interrupted, an
emergency stop signal is sent to the PC. The output stage error is indicated by the second LED from the
right (red, LED2).
3. In case of an emergency stop (no matter if mushroom button or status error) the relay for the holding
brake is switched off, so that the mechanical brake is blocked (if present).
4. In case of missing supply voltage, an emergency stop signal is sent to the PC, so that the software does
not continue uncontrolled.
5. If the watchdog is active (see below), relay outputs and step signals are only enabled if a valid
watchdog signal is detected.
Watchdog (charge pump)
While the PC is switched off, during booting or whenever the control software (Mach3 etc.) is not started, the
LPT signals are undefined. In unfavorable cases, such as when a dongle driver periodically polls the port, even
recurring clock signals can be generated, which can trigger dangerous machine movements. To prevent this, the
breakout board has a so-called watchdog circuit.
