Current RC3 channel value from command line (MAVproxy)

Can I read/write value, for example, for throttle, from command line ? I can set RC3_* parameters, but there are only max/min settings or so. May be exists way to change current throttle value from MAVproxy without RC transmitter ?

@Dmytro Yes, you can use MAVProxy to set the channel value directly like this:
rc 3 1300

Thank You!