Remote wire feeder using binary phase shift keying to modulate communications of command/control signals to be transmitted over a weld cable
The present invention is directed to a system and method of remotely controlling a welding machine with command signals transmitted to the welding power source across a weld cable connecting the power source to a remote device, such a wire feeder. A transmitter transmits the control commands containing desired welding operational parameters to a receiver disposed in the power source across a weld cable also designed to carry welding power from the power source to the wire feeder.
1. A welding-type system comprising:
a power source configured to deliver welding-type power at a terminal thereof;
a remote device connected to receive power from the power source via a weld cable connected to the terminal;
a transmission assembly connected to the remote device and configured to encode control commands onto a carrier wave using phase shift keying (PSK) and to transmit the encoded control commands across the weld cable;
a receiver connected to the power source and designed to receive and decode the encoded control commands from the weld cable; and
a circuit connected to the weld cable and designed to improve signal quality of the encoded control commands over that produced without the circuit, wherein the circuit increases impedance at a frequency corresponding to the carrier wave at the terminal of the power source and an input of the remote device.
2. The welding-type system of claim 1 further comprising a controller connected to the power source and the receiver and configured to process the control commands and adjust welding-type parameters accordingly.
3. The welding-type system of claim 2 wherein the control commands include at least one of voltage and current settings, output modes, trigger signals, ON-OFF commands, and wire feed settings.
4. The welding-type system of claim 1 wherein the transmission assembly is configured to transmit encoded control commands when the power source is delivering welding-type power and when the power source is not delivering welding-type power.
5. The welding-type system of claim 1 wherein the transmission assembly is further configured to encode control commands via either narrow band binary PSK (BPSK) or quadrature PSK (QPSK).
6. The welding-type system of claim 1 wherein the circuit includes at least one of a noise-reducing capacitor attached at the terminal of the power source, an LC tank circuit attached at the terminal of the power source, and an LC tank circuit attached at the input of the remote device.
7. The welding-type system of claim 6 wherein the noise-reducing capacitor is arranged to perform as a low-pass filter and the LC tank circuits are arranged to increase impedance at a frequency corresponding to the carrier wave at the terminal of the power source and the input of the remote device respectively.
8. The welding-type system of claim 1 wherein the remote device is a wire feeder.
9. The welding-type system of claim 1 further comprising a first coupling transformer connecting the transmission assembly to the weld cable and a second coupling transformer connecting the receiver to the weld cable.
10. A method for manufacturing a remotely controllable welding-type system comprising:
providing a power source capable of selectively supplying a welding power and a standby power over a weld cable;
operably connecting to the weld cable a remote device having operator controls;
configuring the remote device to communicate to the power source via a transmission protocol over the weld cable while the power source is supplying the welding power and while the power source is supplying the standby power;
providing a resonance circuit at one or more terminals of the power source;
tuning the resonance circuit to match a frequency of narrow-band binary phase shift keying (PSK) communication over the weld cable; and
providing improved transmission quality over the weld cable via the resonance circuit by at least one of filtering high frequency noise and increasing impedance at terminations thereof.
11. The method of claim 10 further comprising configuring the remote device to communicate control commands of the operator controls of the remote device to the power source.
12. The method of claim 11 wherein the control commands include at least one of ON-OFF commands, output modes, voltage and current settings, wire feed settings, and trigger signals.
13. The method of claim 10 further comprising configuring the power source to communicate to the remote device via the transmission protocol over the weld cable while the power source is supplying the welding power and while the power source is supplying the standby power.
14. The method of claim 10 further comprising configuring the remote device to communicate to the power source by modulating messages of the transmission protocol onto a transmission frequency via PSK.
15. The method of claim 10 wherein the step of improving transmission quality includes at least one of attaching a low-pass filter across output terminals of the power source, and integrating a second resonant circuit with the weld cable at inputs of the remote device.
16. The method of claim 15 further comprising selecting the resonant circuits to cause increased impedance at terminations of the weld cable for a transmission frequency of the remote device.
17. The method of claim 15 further comprising selecting the low-pass filter to permit transmission of a transmission frequency of the remote device and to attenuate noise at frequencies higher than the transmission frequency.
18. A communication assembly for a welding-type system comprising: a transmitter connected to a remote welding-type device and configured to transmit control commands over a weld cable; a receiver connected to a power source and configured to receive the control commands from the weld cable; a controller configured to adjust weld parameters according to the control commands; and a signal-to-noise ratio (SNR˜ coupling circuit connected to at least one of output terminals of the power source or an input of the receiver; wherein the transmitter of the remote welding-type device and the receiver of the power source each comprise a transceiver for bi-directional communication on the weld cable, wherein the SNR coupling circuit is arranged to set a peak impedance for at least one termination of the weld cable at a frequency on which the transceivers transmit; and wherein the frequency is an average frequency of multiple frequencies on which the transceivers transmit.