Rule 6.3 The Link

[chompalot]

Now Im confused do I have to rewire my bot with a switch to power down the RX or not?

Si
http://www.chompalot.co.ukwww.chompalot.co.uk

[lex]

Cheers Ed. Suits me- one less thing to fail...

[storm]

Simon : No.

Ed
http://www.teamstorm.comhttp://www.teamstorm.com

[shredderteam]

Ed/Simon/John

4.10 in its past form has been removed in version 1.2 of the rules which is due release May 1st.
It was removed after feedback that suggested it was contradictory to rule
6.4, which has also been re-worded in version 1.2 in order to clarify.
This was part of the process of re-wording to make things more clear that has been requested through feedback from the community.

It was always the intention that RX switches be mandatory, this does not constitute a rule change.

To explain a little better why the RX switch is required.
Loss of power to the RX is an entirely different failure mode to loss of signal (i.e turning off of TX). It can result in some systems in not only losing power to the RX but also the failsafe which is in line with it. This can in turn result in a servo based system in the servo staying in last position, which in worst case means the robot will continue to move/power its weapons.
Where a code-based system is utilised, if this is not set up to return to neutral on loss of power, this can also result in a continuation of movement.

To conclude:

An on/off switch for you RX is a mandatory requirement for all Featherweight, Lightweight, Middleweight, Heavyweight and Superheavyweight robots; in practice this switch when off must place your robot in failsafe status.

I hope that clarifies the situation.

Regards
Samuel Jones
FRA Safety Executive

[chompalot]

Hi Samuel
No probs Ill do a little rewiring, but, is this switch just for a tech check? if so can I put in a link which defeats the relay which switches on the receiver battery power and just use the receiver power switch to demonstrate power down of the receiver. then after the tech check fix the link back in place and secure with say tywraps so the switch isnt so much of a weakness. Or has it got to be always be able to switch off the receiver even in the arena?

[m2xt]

Sam, this requirement for the robot to place your robot in failsafe status when the Rx is off is a departure form the Mentorn rules. This will in effect mean that 4QD DCI boards and some PCM only systems no longer meet the FRA rules.

Where a code-based system is utilised, if this is not set up to return to neutral on loss of power.. The PCM system cannot output a neutral signal (say 1.5mS) because it has lost its power. This means there has to be a further level of failsafe required. Speedos such as Vantecs and Roboteqs are fine because they have their own built in failsafe logic but that is not the case for all. The same consideration has to be applied to weapons channels as well.

If I understand the above correctly, even those bots with BECs require this switch. It may help if you could explain the safety implications behind this new rule and does this switch have to be accessible without the use of tools?

Paul

[big_nipper]

Sam, dont mean to pick an argument but the way I understand it is that you are going to be altering the tech check to test what happens with a loss of rx power. Have you tried leaving a robot in a room full of other robots and txs and then turned the rx power off while the robot is on the bench and see what happens!

I can understand where you are coming from as Ive seen quite a few flat rx batterys and if they power servos then the failsafes that are powered from them will also fail to work. But if you power the Rx from the main robot battery then I would have thought it to be acecptable to omit the Rx switch as if the rx loses power then so would the speed controller. If the Cables between the Speed controller and Rx became disconnected then the Speed controller would shut down anyway (All models Im aware off)

People should be aware that a good Rx & Tx setup can have an outdoor range of over 1 mile and if there is a kid playing with his remote control car nearby and your robot is in failsafe mode then it could start following his cars movements!

Ive just built a feather speed controller that supplies power to the rx from 4 seperate cables. Does this mean I need an rx switch on each of these or do I have to alter the speed controller to have an Rx power switch. At the moment it only has a removeable link and I know quite a few others that are the same. We also have an IBC speed controller and this also has a BEC would this also mean I have to switch this!

If its required then I should have read the rules better and will change the robots but I dont have time to do it before Wales.

Just to refresh my views. If you have a seperate Rx battery then there must be a Rx switch in addition to the link, but only if you have a seperate Rx battery.

[shredderteam]

Ok.
Were aware that there are issues with this rule for some RX set-ups and the safety committee currently have it under review and testing to see if theres a more all encompassing way of wording the rule.

For now though Ill make it as simple as possible.

A robot on loss of power to the RX must failsafe/cease movement on both weapons and drives.

A way for the Tech check personnel to check that the robot does failsafe/cease movement under these conditions must be built into the robot and be easily accessible during tech check.

This is a common failure mode that people need to take in to consideration when building their robots.

Since we at present cant guarantee an arena that will contain all eventualities at ALL events we have no other option but to make sure the build rules cover all the failure modes were aware of.

Hope that helps

Sam
FRA Safety Executive

[mute]

A couple of things:

1. I thought all arenas had a classification and should be able to contain a run away bot if it fails safe or not.

2. If the Rx is powered by a battery eliminator will you need a switch to simulate a BEC failure?

3. Are we going have a device to simulate what will happen if the Rx Crystal falls out as I have seen this happen a number of times?

Also are provisions going to be made to test all combinations of PCM/PPM & Speedo/Interface for this new mode of failure? Id hate to turn up to an event only to be banned by a new rule!