This relay is wired as a Dual - Single Pole Double Throw relay.
The main intention is to control a wood router spindle motor through M3/M5 control commands in G-code software.
Both relays are activated by a single ACTIVE LOW signal, connected to either S1 or S2.
The unit requires a CP signal (Charge Pump/50%PWM type signal) with a frequency between 9KHz and 13KHz to enable the relays. Frequencies below or above this rate will disable the relay control.
The board requires an end user supplied 5V power source to energize the relays and also power the electronics.
The connections from left to right (as seen in the photo) are:
(5V) (CP) (S1) (S2) (GND)
The CP/PWM type signal is used to keep relays from triggering by random pulses on the signal (S1 or S2) pins that can happen when a computer system initially boots up or a program takes control of the parallel port. The CP signal must be between 9.0KHz and 13.0 KHz for around 1/2 second before the Signal pins can cause the relays to be engaged.
The relay kit comes with the board shown above as well as all of the 14ga. wiring shown, and also includes an IEC 110VAC 14ga. power cable, an IEC power inlet and a 110VAC power outlet. The setup can be wired as such:
The signal wires can come from a BOB like the (BOB_DB25
) in the accessories section. +5V/GND can come from a user supplied 5V wall wart or USB type power supply.
Before connecting the logic side of the relay kit, use a volt meter to verify that the CNC Computer program (like Mach3/4 or LinuxCNC/MachineKit) is properly setting/clearing the Relay Signal pin by turning the meter to DC volts. Place the black meter lead on the GND (i.e. DB-25) of the BOB and the red meter lead on the signal source (i.e. DB-17 or as set in software), with the software setting the active output for active low
. Then engage and dis-engage the spindle while noting the voltage levels. Active ON voltage level should be below 1.0V, while the inactive state should be above 2.0V. Once the relay control signal is verified, it can be connected to the relay board along with the CP and +5V/GND. Again test the software spindle control with 5V/GND, CP and relay signal connected. When the software controls the relays to be ON, the relays should click closed and two red LEDs should turn on. For more information on software setup read the software instruction manual.
Debugging:If the relay does not turn on when commanded, and the Signal source reads properly as described above, and 5V/GND is properly connected, then the CP signal may not be within the 9.0KHz to 13.0KHz range. A simple debug procedure can test the relay (assuming the signal source is in the active low ON state and the 5V/GND are properly powered). There is a set of 5 holes on the right hand side of the board (see picture above). If the square pad is called Pin 1, then count up to Pin 3, and make a small temporary jumper connection between Pin 1 and Pin 3. This bypasses the requirement for the CP signal. Do not
run the relay board in the bypass/debug condition as it removes the safety feature of having the Charge Pump/PWM signal.
Only make AC power connections to the relay board after
the CNC control of the relays has been verified, and NEVER
make any connections with the AC power cord connected to live AC power!
The system requires the use of high voltage power, which if touched can be harmful or fatal. Assembly and use should only be attempted by a qualified individual. Order this unit only if you can have a qualified person that understands the safety concerns of working with high voltage available to properly set up this hardware. If you do not have a qualified individual that can assemble the unit, do not purchase it.
The main wiring of this kit should be placed inside an enclosure so that none of the free wiring provided (excluding the IEC power cord) can be accessed.
After assembly, but before applying power, make sure that all connections are correct and that there are no stray wires exposed that can be touched or cause a short circuit.
The unit does not provide any safety fuses or circuit breakers for over current protection. If such features are needed, a recommendation would be to use a multi-outlet strip with built-in circuit protection that can handle the rated amperage of the spindle motor used. The maximum rated amperage of the relays used in the kit is 10 amps.