Micromill power/relays identification

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robertjenkins
Posts: 10
Joined: Fri 16 Apr , 2021 13:28 pm
Hardware/Software: Denford Micromill 2000

Micromill power/relays identification

Post by robertjenkins » Mon 26 Apr , 2021 12:08 pm

I have a problem with my Micromill 2000 estop. The pin (a25 on the 96 way connector) remains permanently low. When I turn on the machine with the key, the front red light comes on, there is the sound of a relay clunking, and I get power to the Baldor board. But I am having troubleshooting because I cannot identify which relay is which, and my machine doesn't seem to closely resemble any pictures I have seen

Here is a picture of the back. There are two small relays and then the bigger white thing looks like a relay
https://drive.google.com/file/d/1qiI-ue ... sp=sharing

(On the right is what I assume is the spindle control board but I can't find documentation that identifies the inputs and outputs on this version)

There are two switches at the front which are not physically connected to anything. They seem to control a relay that I can hear but not see:

https://drive.google.com/file/d/1C5zAWE ... sp=sharing

Is there a big relay underneath?

Thanks

MadeForThat
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Re: Micromill power/relays identification

Post by MadeForThat » Mon 26 Apr , 2021 17:32 pm

I have not heard of a larger relay below the machine, but I can say if I were trying to identify the issue, I would start by fixing your estop button. the 2 switches that are not physically connected, are the estop button's. they should be attached to the estop button like so:
71YA0pZkelL._AC_SL1500_.jpg
71YA0pZkelL._AC_SL1500_.jpg (122.49 KiB) Viewed 1434 times
not the same switches or estop button, but you can see how the switch is mounted to the bottom of the button.

Estop buttons are normally closed, so if the wire is damaged, the stop will activate (failsafe) seeing as your switches are flopping around, its possible that one is damaged and breaking that loop.

robertjenkins
Posts: 10
Joined: Fri 16 Apr , 2021 13:28 pm
Hardware/Software: Denford Micromill 2000

Re: Micromill power/relays identification

Post by robertjenkins » Mon 03 May , 2021 11:19 am

OK thanks. I have put the switches back on the ESTOP switch since as far as I can see neither is faulty.

It would be helpful to know which relay is which. In the photo, I assume the big white relay is the main relay. But there are also two small blue 24V relays to the left of that relay. I assume one of them is the spindle guard relay? But which, and what is the other one?
Last edited by robertjenkins on Mon 03 May , 2021 15:10 pm, edited 2 times in total.

robertjenkins
Posts: 10
Joined: Fri 16 Apr , 2021 13:28 pm
Hardware/Software: Denford Micromill 2000

Re: Micromill power/relays identification

Post by robertjenkins » Mon 03 May , 2021 13:00 pm

I've realised that what I previoulsy thought was a relay is in fact the Guardmaster solenoid. I can't see the Guardmaster wiring on any of the schematics, but nothing seems to be adrift.

Anyway, I still have a problem with the ESTOP. TB1 seems to be where the ESTOP signal enters the circuit board. A red wire on pin 6, with a capacitor to ground on pin 2. According to the schematic, when the ESR is made, the pins 2 and 6 are connected, thus pulling pin 6 to ground. I don't know where the ESR is, but it seems to be working because when I turn the key, the circuit is made (and so pin 2 goes low). I assume, then, that when the ESR is off, pin 6 is supposed to be high (but it never is). I would imagine that there is supposed be a pull-up resistor somewhere to do this. Am I right? If so, where is this resistor (on the circuit board?)

MadeForThat
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Re: Micromill power/relays identification

Post by MadeForThat » Mon 03 May , 2021 21:20 pm

Hey Robert, Can you take a picture of your schematic that you are working with? In Microsoft paint if you could circle the points of interest, it will help me understand what you are saying.

robertjenkins
Posts: 10
Joined: Fri 16 Apr , 2021 13:28 pm
Hardware/Software: Denford Micromill 2000

Re: Micromill power/relays identification

Post by robertjenkins » Fri 07 May , 2021 16:57 pm

I am looking at these relays
IMG_0349.JPG
IMG_0349.JPG (75.79 KiB) Viewed 1302 times
and comparing them with the circuit diagrams in the "Micromill 2000 Denstep" PDF file which is in a sticky post at the top of this forum. (I'm not sure there's any point in reposting those documents here.) There are points of similarity but also a lot of differences.

My overall aim is to replace the Denford control circuitry (which is fried) with new generic drivers, while retaining the power circuitry and safety features. This means that I want to find both the right ESTOP input and also the 24DC supply that I can use for the new drivers.

In the PDF, there is a 24 AC input on TB11, and I have that. It comes from the transformer via the big white relay. I'm not sure what this is AC supply is for or why it goes to the control board. But in any case I need the 24 DC input. On the PDF this is shown as being available on TB10 but on my machine there is no DC input there. There is a PSU on the chassis with a 24 DC output, here
IMG_0350.JPG
IMG_0350.JPG (58.5 KiB) Viewed 1302 times
but the wires coming from it are rather thin and don't seem to lead to any of the board connectors, which makes me wonder whether this unit is actually being used to drive three steppers. Basically I am confused because I cannot find a document that shows the wiring for the machine I have actually got.

robertjenkins
Posts: 10
Joined: Fri 16 Apr , 2021 13:28 pm
Hardware/Software: Denford Micromill 2000

Re: Micromill power/relays identification

Post by robertjenkins » Fri 07 May , 2021 17:19 pm

There is also the schematic PDF "schematic micromill" which shows plugs and connectors which I don't have (eg PL1, PL2) but in any case shows the 24 AC going to a bridge rectifier but no reference to the Siemens PSU which I posted the picture of.

Martin
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Re: Micromill power/relays identification

Post by Martin » Mon 10 May , 2021 13:58 pm

The Emergency Stop Relay is the relay directly to the left of the Sprint 400 spindle drive.

robertjenkins
Posts: 10
Joined: Fri 16 Apr , 2021 13:28 pm
Hardware/Software: Denford Micromill 2000

Re: Micromill power/relays identification

Post by robertjenkins » Mon 10 May , 2021 15:37 pm

thanks

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