Australian Monitor HSP Amplifier Driver

Version 0.9

Controls Australian Monitor HSP Series power amplifiers (HS120P, HS250P, HS2120P, HS2250P, HS4120P, HS4250P) over RS-232 using the manufacturer-documented ALMA Serial Command Protocol.

Features

- Power on / standby with feedback

- Per-output volume in dB or 0-100 percent (slider-friendly), volume up/down

- Per-output mute with feedback and events

- Input-to-output source routing

- Preset save and recall

- Amplifier fault and temperature warning monitoring with events

- Comms-lost detection and events

- Telnet debug console for diagnostics

Wiring (RS-232)

The amplifier's RS-232 port is a 3-pin 3.81mm Euroblock (Phoenix) connector labelled TXD, RXD, GND on the rear panel. The data lines must be CROSSED to the control system:

- Amp TXD to processor RX

- Amp RXD to processor TX

- Amp GND to processor GND

Serial settings are fixed at 115200 baud, 8 data bits, 1 stop bit, no parity, no flow control. The driver applies these automatically - just select the processor serial port in Driver Properties.

RTI XP serial port (RJ45, T568B)

RTI XP processors present each RS-232 port on an RJ45 jack wired to the T568B standard. Cut one end off a standard patch lead and land these three conductors on the amplifier's Phoenix block (note the cross):

- Blue (RJ45 pin 4) = processor GND to amp GND

- White/Blue (RJ45 pin 5) = processor RX to amp TXD

- Green (RJ45 pin 6) = processor TX to amp RXD

So the processor's transmit (Green) lands on the amp's RXD, and the processor's receive (White/Blue) lands on the amp's TXD.

If the cable is T568A

The blue pair is identical in both standards (Blue = GND, White/Blue = RX). Only the transmit wire changes: on T568A the processor TX is ORANGE (pin 6), not Green. Check pin 1 on the RJ45 plug - White/Orange means 568B (use Green for TX), White/Green means 568A (use Orange for TX). If unsure, twist Green and Orange together for the TX connection - it is harmless, because whichever wire is not the transmit line is the unused DCD line and flow control is off.

Important

- Signal ground (Blue) must be connected - RS-232 will not work without it.

- Use a known-good cable. A broken conductor or a crossover patch lead gives zero communication even when everything else is correct.

- Plug the RJ45 into the same physical RS-232 port number selected in Driver Properties.

Setup

1. Add the driver and select the Serial Port wired to the amplifier.

2. Set Channel Count to match your model (HS2250P = 2).

3. Leave Login Required off unless security has been enabled in the amplifier's DSP software.

4. Wire volume/mute/power commands to buttons, or drop the per-output quick-control tags (Output 1 Volume Up, Output 1 Mute, etc.) onto pre-tagged buttons.

Volume Mapping

The amplifier works in dB. For sliders and percent displays, the driver maps dB to 0-100 percent across the configurable range Volume Slider Min (default -60 dB) to Volume Slider Max (default 0 dB). Volume Up/Down move by the configured Volume Step (default 2 dB).

Volume Sliders

To wire a PERCENT volume slider for an output:

- Value: bind to "Output N Volume (percent)" and set the Graph Scale to Minimum 0, Maximum 100.

- Command: "Volume Set (percent)"; set the Output parameter to Output N and set Dynamic Parameter to "Percent (0-100)".

To wire a dB volume slider instead:

- Value: bind to "Output N Volume (dB value)" and set the Graph Scale to Minimum -60, Maximum 0 (or your preferred dB range, e.g. -128 to 12).

- Command: "Volume Set (dB)"; set the Output parameter to Output N and set Dynamic Parameter to "Level dB".

(The "Output N Volume (dB)" string variable is for text display only - a slider needs the numeric "Output N Volume (dB value)".)

IMPORTANT - where the Graph Scale is set: a slider's display range is set on the SLIDER WIDGET itself, in its Value binding's "Graph Scale" box (Minimum / Maximum) - NOT in Driver Properties. The "Volume Slider Min/Max (dB)" settings in Driver Properties only control the driver's dB-to-percent conversion for the percent feedback; they do not change a slider's range. For a percent slider and a dB slider to sit at the same height, set the dB slider's Graph Scale to the same dB range as Volume Slider Min/Max (default -60 to 0). A dB value like -40 left on a 0-100 Graph Scale will peg at the bottom and look broken even though the feedback is correct.

Each output's slider must point BOTH its Value variable AND its Command Output parameter at the same output. If you copy a slider to make another, re-point both - changing only one (or copying without re-selecting the Value variable) makes the slider track or control the wrong channel.

Feedback Variables

- Power On / Standby / Power Status

- Per output: Volume (dB), Volume (percent), Mute, Source, Fault, Name

- Device Name, Serial Number, Comms OK, Any Fault, Temperature Warning

Events

- Entered/Exited Standby

- Comms Lost / Comms Restored

- Fault Detected / Fault Cleared, Temperature Warning

- Per-output Muted / Unmuted

- Preset Recalled

Debug Console

Telnet to the processor on the Debug Console Port (default 12530). Type help for commands. Useful commands: status, probe (fires a protocol probe and logs the replies), raw (send any ALMA command verbatim).

Troubleshooting

- No feedback: check TXD/RXD are crossed (amp TXD to processor RX). The Comms OK variable goes true on the first reply.

- Commands rejected with error: security may be enabled on the amplifier - set Login Required and enter the username/password.

- Use the debug console probe command to verify the protocol end to end.

Tested Configuration

This driver has been hardware-tested against the Australian Monitor HS2250P (2-channel) only. The 1-channel (HS120P / HS250P) and 4-channel (HS4120P / HS4250P) models use the identical ALMA protocol and the same driver code - outputs 1 through 4 are handled the same way - but outputs 3 and 4 have not been verified on hardware. Set Channel Count to match your model.

Slider Troubleshooting

If a volume slider sticks, snaps back, or shows the wrong position: confirm its Value is "Output N Volume (percent)" with Graph Scale 0-100, and its Command is "Volume Set (percent)" with Output N and Dynamic Parameter "Percent (0-100)". If you copied a slider, make sure there is not a second slider widget left overlapping the first, and that both the Value and Command point at the intended output. Re-download to the processor and reload the panel after changes.

Licensing

The driver runs at full functionality for a 120-minute trial each time it loads. After the trial, status feedback keeps working but control commands are blocked until a licence key is entered. To licence: read the processor MAC from the "MAC For Key" system variable, buy a key from https://smarthomeprogramming.com.au, and paste it into the Licence Key field in Driver Properties. Each key is bound to one processor MAC. The "Licence Status" / "Trial Time Remaining" sysvars and the TRIAL_WARNING / TRIAL_EXPIRED events report state.

Support

Smart Home Programming - https://smarthomeprogramming.com.au - david@smarthomeprogramming.com.au