Tag Archives: Mast Automation

Radio Mast Automation – Part 5: Control Modification

Since my last blog on Mast Automation when I thought I’d finished the project, I have made some changes to my weather station which means I no longer have an output to the mast controller, this output used to trigger the mast to lower when the wind speed hits 30 mph.

I decided to update the discontinued version of my Programmable Logic Controller (PLC) with a Rievtech PR-18DC-DA-R from Audon Ltd, this unit is a direct replacement for my old PLC and has 12 Inputs and 6 relay Outputs.

Rievtech PLC

The PLC accepts a number of input types, in my application I’m simply switching a voltage state with the exception of one of the inputs which is configured as an Analogue input, to which I have connected my mast mounted Anemometer as a means to trigger mast lowering during unsafe wind conditions.


Adafruit 1733



  • Height (base to center): 105mm / 4.1″
  • Center out to Cup: 102mm / 4″
  • Arm Length: 70mm / 2.8″
  • Weight: 111.8g

Wire Dimensions:

  • Wire Length: 99cm / 39″
  • Plug Length: 30mm / 1.2″
  • Diameter (thickness): 4.8mm / 0.2″


  • Output: 0.4V to 2V
  • Testing Range: 0.5m/s to 50m/s (111.8 mph)
  • Start wind speed: 0.2 m/s
  • Resolution: 0.1m/s
  • Accuracy: Worst case 1 meter/s
  • Max Wind Speed: 70m/s (156.5 mph)
  • Connector details: Pin 1 – Power (brown wire), Pin 2 – Ground (black wire), Pin 3 – Signal (blue wire), Pin 4 not connected

I tested the output  with help from my better half by driving at steady speed and monitoring the output from the anemometer:

  • 0 mph = 0.40  mV
  • 25 mph = 0.75 – 79 mV
  • 30 mph = 80 mV
  • 31 mph = 81 – 88 mV
Anemometer mounted on 2m/70cm H/V relay switch box

I mounted the anemometer to the top of my mast to get a representative wind speed, the next job was to strip out the old PLC from the control cabinet.

Starting mods, (hand held winch controller on top of cabinet)

I needed to make several changes from the original design in order to free up one of the PLC’s inputs, also out of the 16 Inputs only the first 6 allow analogue inputs, so some moving of inputs was needed along with some minor works to the LED voltages and override/luffing switch.

Completed Cabinet

All went back together quite nicely but an intermittent problem remained after the PLC replacement in that when the mast completed the mast raise cycle, the motor would immediately reverse and the mast would lower.

Hooking up the laptop to to the PLC, I selected ‘live monitoring’, this displayed the input and output condition, this showed that after operating the ‘raise’ toggle switch (centre bias On – Off – On centre off), the ‘lower’ switch input also went and remained high. This output to the PLC caused the motor to immediately  change direction and lower the moment the mast raised sensor was triggered.

To reduce the chance of a repeat problem occurring, I modified the replacement DPDT switch wiring so that both poles need to switch in order for a signal to pass.

switch wiring

Prior to starting the upgrade works I had the programmed PLC on the bench and I thoroughly tested all control permutations by simulation using the software from Audon Ltd to ensure correct operation.

PLC Modified block diagram (Program File for use with xLogicsoft)

As you can see, the logic has grown with the project, I’m sure this could be significantly simplified, however, it works for me.

Mast Control Logic

Pressing the Emergency Stop button will inhibit any operation and reset any timers which are running.

Raising the Mast

Conditions –

  • E Stop not pressed. (Input 1004)
  • Top Securing mast pin IN. (Input 1008)
  • Mast in the lowered position. (Input 1006)

Trigger –          Switch input momentary high. (Input 1003)

Action –

  • Lower switch inhibited.
  • Switch input via wiping relay with a 1 second ON timer to ensure momentary trigger to the next stage.
  • 36 second up timer start to operate Up relay (fail mechanism in case the ‘raised’ sensor fails).
  • Up relay closes to energize motor drive. (Q002)
  • After expiry of Up timer or on activation of the Up sensor, Up relay opens.
  • Mast raised output relay energizes. (Q003)

Lowering the Mast

Conditions –

  • E Stop not pressed. (Input 1004)
  • Top Securing mast pin IN. (Input 1008)
  • Mast in the raised position. (Input 100C)

Trigger –          Switch input momentary high. (Input 1005)

Action –

  • Raise switch inhibited.
  •  Switch input via wiping relay with a 1 second ON timer to ensure.momentary trigger to the next stage.
  • 39 second down timer starts to operate Down relay (fail mechanism in case the ‘lowered’ sensor fails).
  • Down relay closes to energize motor drive. (Q001)
  • After expiry of Down timer or on activation of the Down sensor, run on timer operates for 0.15 seconds to take slack off winch cable.
  •  After expiry of run-on timer, Down relay opens.
  • Mast lowered output relay energizes. (Q004)

Wind Speed Triggered Auto Lower

Conditions –

  • E Stop not pressed. (Input 1004)
  • Top Securing mast pin IN. (Input 1008)
  • Mast in the raised position. (Input 100C)

Trigger –           Wind measured via Anemometer at 28 mph for 15 seconds. (Input A1001)

Action –

  • 0.4 – 2v Anemometer to Analogue Threshold Trigger output set go high at 80 mV and off at 76mV, these values equate to ~28 mph and ~24 mph respectively.
  •  ‘On Delay’ timer from analogue threshold trigger set for a sustained output of 15 seconds duration before the next stage is enabled in order to reject gusts.
  •  ‘Off Delay’ timer set to 10 minutes, if no input from the ‘On Delay’,  ‘Off Delay’ resets.
  • Whilst the ‘Off Delay’ timer is running, the WX Amber LED is lit. (Q005)
  • Output from ‘Off Delay’ to wiping relay timer set to 1 second to ensure a momentary output to the next stage.
  • 39 second down timer starts to operate Down relay (fail mechanism in case ‘lowered’ sensor fails).
  • Down relay closes to energize motor drive. (Q001)
  • After expiry of Down timer or on activation of the Down sensor, run on timer operates for 0.15 seconds to take slack off winch cable.
  •  After expiry of run-on timer, Down relay opens.
  • Mast lowered output relay energizes. (Q004)

Battery Charging Process

The winch has 3000lb capacity from Winch-It and is powered by a 12v car battery with a capacity of 45Ah – 360cca.

Normal Operation –    4.5w solar panel connected to the battery via CMP Solar Charge Controller.

Automatic Operation –

Trigger –       After 4 operations of the motors (raise & lower twice) or Weekly – Sunday 01.00

Action –

  • Multi-pole relay energizes after a 2 second delay via Q006, this:
  • Disconnects the solar panel.
  • Applies mains to a 4A output battery charger (charger sized for Ah of battery).
  • Connects the battery charger output to the battery.

Charging ceases when:

  • Battery terminal voltage reaches 14.14v (Over-voltage detection module to Input 100A).
  • 8-hour battery run timer expires.

Manual Operation –

Charging Start – Push button in control cabinet (Input 100B)

Charging Stop – Cursor key on PLC (C3)

Note –

If the battery charging cycle has started and the motor (either up or down) is operated, charging will cease and resume after a delay of 2 seconds after the motor has stopped.

Luffing the Mast

Conditions –

  • E Stop not pressed. (Input 1004)
  • Top Securing mast pin Out. (Input 1008)
  • Bottom Securing mast pin In (Input 1002)
  • Mast in the lowered position. (Input 1006)
  • Luffing switch set to On (Input 1007)

Trigger –           Momentary switch (raise or lower) (Inputs 1003 or 1005)

Action –            Operating the Luffing switch supplies power to the wireless receiver and manual switch which came with the Winch-It kit via a relay , the supply for this is taken from the Luffing/Override indicator LED, (the Luffing switch is a Double Pole Double Throw On – Off – On, the LED is fed from one side of the switch).

A further change to the control is to from latching to momentary switch operation allowing the motor to be ‘inched’ via the wireless handset or panel switches in the control cabinet.

Using the handset allows the mast to be walked down whilst lowering or the reverse when reinstating the mast to the vertical.


Operating the Override switch bypass all limit switches and enables momentary manual control.

Amber LED indicating high wind has triggered lowering the mast and inhibiting it from raising whilst lit.
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Radio Mast Automation – Part 4 – FINISHED (or so I thought)!

It has taken quite a while and a fair bit of work, but the ham radio mast automation project was finally  commissioned and tested today.

The links to the previous parts are here –

The main bulk of the final part was the drawing out of cables from my 40mm duct and replacing the aluminium tube from the rotator with a slightly longer one, this will give me more room for antennas should they be needed at a later date.

So that I dont have to run more antenna cables from the mast to the shack, I have fitted an Ameritron RCS-8V mast head 5 input antenna relay linked back to the shack by a multicore cable.

SAM_5640 (Medium)

Mast winched down to allow the longer pole and relay unit to be fitted, while the mast was down, I added some more ‘P’ clips the tidy the convoluted tube.

SAM_5642 (Medium)

The ‘kick’ in the tube allows the mast to sit in the top bracket recess without snagging any cables.

SAM_5647 (Medium)

The cables from the mast were put inside an protective sleeving up to the point where they enter the duct, the cables from the mast are:

  • 1 x RG213 for X200 Co-linear
  • 1 x RG213 for 2m/70cm Beams
  • 1 x RG213 to Antenna Relay
  • 1 x 8 core multicore from Antenna Relay (two cores were used for the beam relay which is separately housed on the mast)
  • 1 x 7 core rotator cable

From the external control, a 12 core multicore cable is also drawn in the duct.

SAM_5652 (Medium)

The 12 core is wired into the shack mast control unit, the unit is currently showing that the mast is in the raised position, a cable from this unit goes to the weather station Hobby Board relay interface.

SAM_5653 (Medium)

The supply for the Hobby Board interface is derived from the 24v supply which is used for the mast sensors (within the interface is a voltage reduction circuit so it operates at 13v).

The Weather Display Hobby Board program has bee set to output a ‘mast lower’ signal if any of these conditions are met:

  • Wind speed exceeds 27kts (31mph)
  • 30 strikes per minute of lighting are detected

The lightning count was originally 8 strikes per minute and as the detector was picking up lightning approximately 30 miles away it triggered the mast to lower, which it did.  As their is no distance calibration, I have increased the strikes per minute as I’m assuming the strike rate will increase as the storm gets closer.

If you have any questions or comments, please feel free to get in touch.

January 17 Update

Without my weather PC running Lightning Data could not be used, in Jan 17 I turned off the PC so now the weather related mast condition is from a standalone wind speed device.

Please see Part 5 HERE.

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Radio Mast Automation: Control – Part 3

Third installment of the thrilling journey to install automation control to raise and lower my 12m radio mast, Part 2 is HERE.

As it was such a lovely few days weather I thought I’d spend some time working on mast automation, the proximity sensors (link to sensor blog) have been installed previously, so it was time to wire them up.

I bought some 10mm convoluted tube and ‘Tee’ fittings from Hilltop Products, 3/8″ P clips came courtesy of  eBay, the existing mast control wiring arrangement was completely removed and replaced with new tube and clips, an 8 core cable (Alarm cable 7/0.2mm) was drawn in, each of the four mast sensors had a unique signal cable, the other four cores were doubled up for 24v power to the sensors.

The ‘Tee’ pieces were ideal to close on the Superseal connector rubber boots and gives a great finish.


I fitted an Emergency Stop button to the side of the mast and added a longer length of cable to the solar panel via a Superseal connector, existing control relays in the battery box were also removed and enclosure holes sealed.

20160604_180638 (Medium)

It was at the point of cleaning up the battery box that I measured the current draw taken by the high current relay when energized, I had factored about 1A, however it turned out to be 2.5A, this meant that my controllers wiring loom switching wires were underrated.

I had neatly lace wired with waxed cord my loom, and it took me ages to undo that good work and replace the switching wires with 0.75mm2 singles, one this was done, it was out with the waxed cord for round two.

The reason so much effort was taken with cable identification and looming was that all the kit had to be striped from the wooden backboard in order for the board to fit back in the enclosure, once in, the kit gets remounted, it’s not a big space to work so I knew I had to make it robust against wires coming out.

20160605_160545 (Medium)

Once installed and powered up, I tested the speed of operation of the emergency stop button, fortunately its as near as instant as I could perceive, so I pressed and released the mast raise switch, and stood back with my hand on the E-Stop in case it overshot the limits and the run timer was set too long, as it was it work perfectly, as did the lowering operation, the picture was taken after I pressed the Battery Charge override button, this disconnects the battery from the solar panel charger as the 4A charge is ON, battery voltage is displayed on the Mast Controller box and when this reaches 14.14v, the PLC will turn the charging relay off, reconnecting the battery to the solar charger once more.

Every four lifts of the mast or every Sunday at 01:00 whichever is sooner will cause the charging sequence to begin, in case the battery is unable to reach the set-point voltage, the PLC will disconnect the charger after 10 hours of use.

The white pipe at the bottom of the enclosure is for a single 12 core to the remote control unit in the shack, this is the next job to wire.

Power to the motor is from  a 45Ah 360A battery, the original 063 type from Halfords was beginning to signs of aging, so I bought the one below from eBay for £24:50 in January 17:

The battery is maintained by a solar panel and after 4 lifts, a 4A charger kicks in, solar panel charging currrent is 502mA:

Current drawn by the motor raising the mast is a little over 23A, the duration is approximatly 47 seconds for the mast to reach full height.

The Load and time taken to lower the mast is a lot lower at 8.86A.

Please see Part 4 HERE.

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Radio Mast Automation Proximity Sensors

This Blog post went into detail on the sensors used for the mast position, I have found reasonably priced ferrous metal inductive proximity switched, these are non contact devices with a detection range of 5mm which is perfect for my application of securing pin detection, feeding into the masts PLC logic controller.

2016-04-09 17.11.08 (Medium)

Sensor mounted below bottom mast securing pin hole, the sensor was fixed the mast by drilling and tapping a 6BA hole, the HSS drill size of 2.3mm for a 6BA tap cost 99p for 10 from Hong Kong, the machine screws which come with the sensor appear to be  imperial and were discarded.

2016-04-09 17.11.16 (Medium)

Test position for alignment and operation checking.

2016-04-10 11.10.42 (Medium)

Lower pin sensor finished with a three pin male Superseal waterproof connection, the female will break out of the 10mm convoluted conduit via a hinged tee piece.

2016-04-10 09.48.15 (Medium)

Top mast securing pin sensor being fitted, this pin stops the mast from tilting down (Luffing), the output from this sensor, like the bottom pin detector will influence the functions available in the PLC controller, for example, if the mast is elevated and the top pin is removed, the mast will not lower as this is an unsafe condition.


The next stage is the mounting of the controller cabinet and wiring which can be found HERE.

Update 20 July 17 – Top proximity failed and had to be replaced, no sign of water ingress and the potting and cable entry look in good order, so not sure what the cause of the failure.

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Radio Mast Automation – Part 1 – PLC or Relay Control

Note – This is the starting point in my mast automation project, several things ‘evolved’ during the overall project, therfore as you read through this and get to the end of the Parts, you can see the changes, tweaks and additions which have improved the project.


My mast has an winch to raise and lower the inner section of the mast.

This project is to fully automate the process and add a level of intelligence into the mix, my requirements list is:-

  • Automatically stop the motor at the top or bottom
  • Run-On when mast lowered to release tension from cable
  • If bottom mast inner securing pin is in – Stop mast from raising or lowering
  • Disallow inputs whilst the motor is either lifting or lowering
  • Safety timer on the motor operation should a limit switch fail
  • Means to stop holding an input button increasing the motor run time
  • Don’t lower the mast if the luffing pin is removed
  • Override to allow either a pulsed automatic operation or manual hold for up & down ignoring limit switches
  • Emergency stop
  • All timing sequences reset on restoring emergency stop or override to prevent motor operation
  • Interface with WX Station to automatically lower
  • Visual display of status – what is doing what
  • Automatic battery charging after a number of counted operations or weekly – whichever comes first
  • Battery charging does not interfere with solar panel charging

I was going to use relays, and made a start on the construction, but the more I thought about interlocking and timers the more unrealistic this option became.

SAM_5618 (Small)

The relay unit currently in use which works fine is shown below, two of the relays are for the raise and lower switches, the other two are for overrides.

SAM_5472 (Small)

My plan is to use a Programmable Logic Controller (PLC) which needed to have 12 inputs and 4 relay outputs.

I found a company on the internet called Audon.co.uk, the model chosen was ELC-18DCD-R-U at £69 ex VAT and I also bought a RS232 programming lead for just under £20 ex VAT, the PLC has a voltage range from 12 to 24v DC is very compact and will do everything I need and more.

A major plus was the programming software is free and very easy to use.


Link to PLC Software Link

Link to PLC Manual

The drawing shows the sensor positions, currently the mast only has up and down limit switches fitted, the upper and lower securing pin detection will be fitted when the parts arrive from the other side of the world.

Mast Contro2l

The way of working will be:

Normal Up & Down

Momentary pressing of the down button on the remote hand held winch unit, will fully lower the mast, pressing the up button will do the reverse.

Luffing the Mast

Luffing (Tilting down) of the mast for maintenance will involve setting the PLC input switch to Luff, this will only lower the mast if the mast is lowered, the lower securing pin is in and the upper securing pin is out.

The logic plan shown below has been imported from the software program into Visio and I’ve added some idents to make it easier for me to fault find at a later date.

Descriptors for the idents is below.

The next stage of the project is to mount the PLC in an enclosure and fit the securing pin sensors, please see Part 2 HERE.

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