Changing a Omnl step wiring issue (1 Viewer)

[Steve and Denise]

I am replacing a rollout type of step for a standard double drop down step due to ground clearance issue,
The rollout one is one touch of the switch and out it goes to maximum then stops, touch the other side of the switch and it retracts fully, this step is fitted with two micro switches a control box and has 8 wires going to it.

My question is can I make the new step operate the same way ie press once to fully extend/retract rather than press and hold, I have looked at fitting an auto retract relay that I assume gets a home signal from the step micro switch when folded, but there is no limit switch for fully extended.

I am thinking I may have to fit a max travel switch to the step and try to use the control box from the original any thoughts.

There are a lot of wiring diagrams on the internet all seem to be switched rather than current sensitive.

 

[Steve and Denise]

Here is a photograph of the step I have removed

 

[SandraL]

Broken Link Removed

Would a schaudt ems03 do the job?

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[Steve and Denise]

Not sure I will have a look to see if is current sensitive ?

 

[tonyidle]

I've never seen an Omnistep with anything more than a step-out switch nor any form of one-touch operation. The Omnistep ignition-on auto-retract function used a capacitor to provide a timed hold for the relay used to retract the step. The simplistic "microswitch" is used to operate an alarm buzzer, handover control to the ignition switch, and to had back control to the manual switch once the step is parked. Under no operational circumstances is it used as a limit switch. Your best bet is to replicate the mechanical operation of your old step by adding the appropriate micro-switches to your new one

 

[andy63]

Would you be able to adapt something like this
Broken Link Removed
Basically a pulsed switched relay..
I rewired my step to switch without the control panel having to be turned on before you could use it and at the same time wired it to close on an engine run signal..
Just the other week I snapped yet another drive shaft as I'm sure I sometimes don't fully open the step before I stand on it..transferring the force to the drive shaft rather than the linkage..
A similar solution of fitting a momentary switch to the step to ensure it deploys fully would be a good idea for me as well..
Andy

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[Steve and Denise]

I've never seen an Omnistep with anything more than a step-out switch nor any form of one-touch operation. The Omnistep ignition-on auto-retract function used a capacitor to provide a timed hold for the relay used to retract the step. The simplistic "microswitch" is used to operate an alarm buzzer, handover control to the ignition switch, and to had back control to the manual switch once the step is parked. Under no operational circumstances is it used as a limit switch. Your best bet is to replicate the mechanical operation of your old step by adding the appropriate micro-switches to your new one

Yes Tony you only touch the switch momentarily and the step extends fully and vice versa, I was thinking a signal was picked up from the buzzer switch on the step mechanism here are a photograph of the one I have removed, as you can see it has two switches I think one to let you know it is in and the other to let you know it’s out, also I think that little black box may control everything.

 

[SandraL]

inoperative electric step

Inoperative electric step Hope someone can help me with this problem,my vehicle is a Hymer starline 655,year 2005,I parked it up end of December 2014.when I tried to enter it in mid-March 2015,the electric double-step would not come out when i operated the switch just inside the door,it was...

www.motorhomefun.co.uk

See post no 4, suggests its current limit .

 

[tonyidle]

That is much more sophisticated than the Omnistep. That 'black box' looks more like it is covering connections rather than anything too clever. I'd expect any relays / electronics to be indoors. That step is how steps should work. I cannot emphasise enough how simplistic the Omnistep is. The only thing that prevents motor burn-out if the switch is held is a thermal fuse (not part of the step).

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[Steve and Denise]

This is the one quite a bit in the box tonyidle

I have it working now but not quite right yet

 

[tonyidle]

I stand corrected . I assume the diagram is of your existing step?

 

[Steve and Denise]

Yes Tony the control box is rated at 3 amps but the step I have fitted takes a fair bit more, so keeps stopping when the load gets a bit much, press again and it completes its travel,
I must admit I am getting out of my depth so it may end up Manuel ie press and hold

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[Steve and Denise]

So it would appear that the Schmidt ems 03 SandraL will do a similar job but has a higher current rating.

I will check the draw on the new step first if it’s within the spec for that relay I think that may be the way to go.

 

[tonyidle]

Yes Tony the control box is rated at 3 amps but the step I have fitted takes a fair bit more, so keeps stopping when the load gets a bit much, press again and it completes its travel,
I must admit I am getting out of my depth so it may end up Manuel ie press and hold ☹

Is it the load or is it a timer? Load sensing stall current is the logical way to do it but in my limited experience control by that method doesn't need to be so sensitive (stall current is invariably more than double the running current). A couple of ohms in series with the motor might solve the problem.

I built a few circuits in the past to do the opposite - stop a motor when load reduced. I used reeds with a series coil wrapped round before electronics removed the need. Mine were used to stop a submersible pump once the Aquaroll was empty .

 

[Steve and Denise]

Is it the load or is it a timer? Load sensing stall current is the logical way to do it but in my limited experience control by that method doesn't need to be so sensitive (stall current is invariably more than double the running current). A couple of ohms in series with the motor might solve the problem.

I built a few circuits in the past to do the opposite - stop a motor when load reduced. I used reeds with a series coil wrapped round before electronics removed the need. Mine were used to stop a submersible pump once the Aquaroll was empty .

When this relay was fitted to the old step it took a long time to fully deploy around 5-6 seconds and the max amps were 2amps,
On the new step at half way through the cycle the current goes above 3amps and stops, so I think it is pointing at current limit more than timer ?

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[tonyidle]

When this relay was fitted to the old step it took a long time to fully deploy around 5-6 seconds and the max amps were 2amps,
On the new step at half way through the cycle the current goes above 3amps and stops, so I think it is pointing at current limit more than timer ?

Agreed. That's an incredibly low limit though. Stall one of those motors and you're heading for 8+ Amps so why is it set so low? It almost suggests a fault.

 

[Steve and Denise]

On the old step there are two gearboxes so very low load on the motor on the spec of the step there is a max rating of 3 amps.
This is it Project 2000 disappearing step

 

[Steve and Denise]

Well the step is now working thanks SandraL I used the Ems-03 works a treat touch hab door switch goes out touch other side of the switch it goes in, touch the dash mounted switch also retracts the step fully only one thing I am notable to do is get the step to retract from the dash end with the engine running, but will retract fine from the hab door switch while running. I may need to seek a bit of knowledge with Carthago wiring.

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[Steve and Denise]

Agreed. That's an incredibly low limit though. Stall one of those motors and you're heading for 8+ Amps so why is it set so low? It almost suggests a fault.

Tony if you check the spec on this step it has a rating of 3 amps

 

[SandraL]

On our Hymer the step doesnt automatically retract on engine start. The buzzer comes on as ignition is turned on and I then manually , yes poor I thought too, press switch on dash to retract step and turn buzzer off.
I suppose its possible to turn engine on just as partner is about to stand on step that disappears.......

 

[tonyidle]

Tony if you check the spec on this step it has a rating of 3 ampsView attachment 434014

I was stating the current draw of a stalled motor. 3A running is likely to be 6 to 8 Amps stalled.

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