Mitsubishi: what module do I need to output 5V to a tank float switch?

Hi, Can someone help me out? Please excuse my terminology because I'm a complete newcomer to PLCs.
The PLC at work is modular/expandable and rack-mounted. I need to connect a float switch identical to this one to the PLC.
https://uk.rs-online.com/mobile/amp...MI8Y7fypzG7AIVzt_tCh2YhQbAEAQYAiABEgIx3fD_BwE
It is normally open. As the water level rises, the switch is made and becomes closed circuit. There are 2 wires coming from the switch and these need connecting to the PLC, such that the PLC can monitor when the switch goes to the closed position. My understanding is that the switch can work from 5VDC.
My question is: what type of module do I need to output 5V to the switch? Do I need to define "switch closed" as an X (input) parameter to the PLC?

Please let me know if you need clarification and I will do my best to clarify.
Thanks in advance.

The linked document says the switch is appropriate for a maximum voltage of 120 VDC or 240 VAC.

Steve Bailey said:

The linked document says the switch is appropriate for a maximum voltage of 120 VDC or 240 VAC.

Click to expand...

It does. That's a maximum voltage , so I was only going to give 5V to meet that requirement. I hope that makes sense, but my knowledge of electricity/electronics is not great.

A more typical DC voltage for industrial sensors would be 24 VDC. Use a 24 VDC power supply and DC sinking input module for the PLC. Connect the +24 VDC to one wire going to the switch. Connect the -24VDC wire to the common terminal on the input module. Connect the other wire from the switch to one of the numbered terminals on the input module.

Steve Bailey said:

The linked document says the switch is appropriate for a maximum voltage of 120 VDC or 240 VAC.

Click to expand...

Steve Bailey said:

A more typical DC voltage for industrial sensors would be 24 VDC. Use a 24 VDC power supply and DC sinking input module for the PLC. Connect the +24 VDC to one wire going to the switch. Connect the -24VDC wire to the common terminal on the input module. Connect the other wire from the switch to one of the numbered terminals on the input module.

Click to expand...

Thanks for your help. I'm still confused though. Are you referring to 3 wires in your description? You say connect 3 times. I must be misunderstanding you. Apologies for my stupidity.

There will be two wires connected to your 24VDC power supply, labeled + and -. There are two wires coming out of your switch. The wire from the + terminal on the power supply connects to one of the two wires coming from the switch. The other wire from the switch connects to one of the PLC module's input terminals. The wire from the - terminal on the power supply connects to the common terminal on the PLC input module.

Steve Bailey said:

There will be two wires connected to your 24VDC power supply, labeled + and -. There are two wires coming out of your switch. The wire from the + terminal on the power supply connects to one of the two wires coming from the switch. The other wire from the switch connects to one of the PLC module's input terminals. The wire from the - terminal on the power supply connects to the common terminal on the PLC input module.

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Brilliant, now I understand the set-up!
I think the only missing piece of the puzzle is the type of Mitsubishi module I need in the PLC - it's a Q-series. I will check in the PLC cabinet tomorrow morning and see what's in there because there might be a suitable module with 'spare' slots/channels on it already.
Many thanks for your help!

5 volt is not the sort of voltage that is standard in digital inputs, more prone to noise and only used in short runs. The PLC will probably already have spare 24v DC inputs, there will probably be an existing 24V power available as well. If you need another card then the one you need (for 24v) is the QX80 16 input card. You will also need to re-configure the PLC I/O as putting a card in the rack will probably stop the processor with an error.

parky said:

5 volt is not the sort of voltage that is standard in digital inputs, more prone to noise and only used in short runs. The PLC will probably already have spare 24v DC inputs, there will probably be an existing 24V power available as well. If you need another card then the one you need (for 24v) is the QX80 16 input card. You will also need to re-configure the PLC I/O as putting a card in the rack will probably stop the processor with an error.

Click to expand...

Fantastic -thanks for the reply! Unfortunately there's no QX80 module in the PLC.
Also the cable run to the PLC to the float switch is about 50 metres, so 5V might be no good.
This is what we've got. Will any of these provide 24V? If not I might have to get tjhe QX80 you mentioned.

Q06UDEHCPU = Universal Q CPU module, 60k step memory, 9.5ns per instruction, Ethernet enabled
Q61P = 100-240 AC input, 5V DV, 6A output
Q312B = CPU base with 12 I/O slots and 1 power supply slot
Q612B = Extension base with 12 I/O slots and 1 power supply slot
QC06B = Connection cable between base units, 0.6m
Q2MEM-2MBF = Linear Flash Card, 2MB
QX10 = 16 point, 100-120V AC (7mA), 16 points/common
QY18A = 8 point relay 240V AC/24V DC, 2A contact, all points independent
Q68AD-G = A/D input module, 8 channel, 16 bit, Current or Voltage (Req A6CON1 or A6CON4)
Q68DAIN = D/A output module, 8 channels, 0 to 12000 0 to 20mA
Q68TD-G-H01 = Thermocouple input module, 8 channels (Req A6CON4)
Q68RD3-G = RTD input module 8 channels (Req A6CON4)
QD62 = High speed counter module, 2 channels, 200kHz, 5/12/24V DC input, (Req A6CON4)
QG60 = Dummy Unit
Q40CBL-3M = Assembled cable with D Sub plug 40 pin 3 meters
A6CON4 = D Sub plug 40 pin Soldering type ,usable for straight out and diagonal out

At the bottom of the rack is a PULS DIMENSION CS5 24VDC power supply. - could this be used?


Thanks

The QX10 would be ok if you don't mind 110v (the switch is rated for that and if it has a spare input.
I think the 24v supply would be ok as it probably is used to power the A/D & D/A modules, it looks like you have a spare slot with the dummy in it so a QX80 card would be ok. Do you have a copy of the program and what IDE was used to program it. There are a number of scenario's
1. Is the PLC password protected (and have you got the password)
2. What IDE was used to write the program (I would suspect it would be either GXDeveloper or GXWorks. if it was GXDEV then even if you do not have the source code & not password protected then it is possible to upload it.
3. If done in GXWorks (Or in the older GXIEC) then it is likely that without the source code you will really struggle, GXIEC & GXWorks uses all sorts of tricks to make the program structured, and unless the symbolic code is downloaded and kept up to date with the running code then it could not be re-constructed correctly.
Even code done in GXWorks or IEC can be uploaded into GX Developer but there will be so many jumps in the program and many memory addresses in the high end range it would be difficult to find how the program works.

I looked at the tech sheet for this switch. Unless I read it wrong, the switch is a two-wire switch. On the connectorized version, the connections are on pins 1 & 2 of 4-pin M12 connector. Therefore, you would connect your PLC input to pin 2 and connect your supply to pin 1. From the description, the switch is a dry contact, hence the wide voltage range. As Parky said, if you have a spare input on the QX10 and don't mind using 110V, that card would work fine. If 24vdc is acceptable, there are many cards you can get to fulfill that need (QX40..., QX41..., QX80..., QX81... It all depends whether you will be switching +24 or 0VDC and how many extra points you wish to have. If you absolutely want 5VDC, the you will need to look at QX70, QX70H, QX90H, QX71 or QX72. Again, it depends if you will be switching +5V or 0VDC.

parky said:

The QX10 would be ok if you don't mind 110v (the switch is rated for that and if it has a spare input.
I think the 24v supply would be ok as it probably is used to power the A/D & D/A modules, it looks like you have a spare slot with the dummy in it so a QX80 card would be ok. Do you have a copy of the program and what IDE was used to program it. There are a number of scenario's
1. Is the PLC password protected (and have you got the password)
2. What IDE was used to write the program (I would suspect it would be either GXDeveloper or GXWorks. if it was GXDEV then even if you do not have the source code & not password protected then it is possible to upload it.
3. If done in GXWorks (Or in the older GXIEC) then it is likely that without the source code you will really struggle, GXIEC & GXWorks uses all sorts of tricks to make the program structured, and unless the symbolic code is downloaded and kept up to date with the running code then it could not be re-constructed correctly.
Even code done in GXWorks or IEC can be uploaded into GX Developer but there will be so many jumps in the program and many memory addresses in the high end range it would be difficult to find how the program works.

Click to expand...

Many thanks again. Very helpful.
The PLC is written with GXDeveloper (ladder logic).
There's no password protection.
Yes, I think the 24V power supply is used for powering the other modules in the PLC.

Just one other thought, If 110v is not acceptable but you do have a spare input on that card (you could check this by checking if all inputs are wired and if any have outgoing connections) and of course a cross reference of the inputs used.
You could use an interface relay so 24volt out to the switch bring this back to an interface relay with 24v coil, then wire the 110 through a contact on the relay.

drforsythe said:

I looked at the tech sheet for this switch. Unless I read it wrong, the switch is a two-wire switch. On the connectorized version, the connections are on pins 1 & 2 of 4-pin M12 connector. Therefore, you would connect your PLC input to pin 2 and connect your supply to pin 1. From the description, the switch is a dry contact, hence the wide voltage range. As Parky said, if you have a spare input on the QX10 and don't mind using 110V, that card would work fine. If 24vdc is acceptable, there are many cards you can get to fulfill that need (QX40..., QX41..., QX80..., QX81... It all depends whether you will be switching +24 or 0VDC and how many extra points you wish to have. If you absolutely want 5VDC, the you will need to look at QX70, QX70H, QX90H, QX71 or QX72. Again, it depends if you will be switching +5V or 0VDC.

Click to expand...

Thanks for the help.
Yes, there are plenty of spare inputs on the QX10 modules.
So I'm trying to visualise the wiring...A wire would go from the QX10 module to pin 1 of the switch (to provide 110v). And from pin 2 of the switch there would be a wire that goes back to the QX10 module (data input)? I hope my terminology is not confusing.

You might find that there is no need to get the supply from the QX module they rarely have a supply only the common. so take the 110v from the supply fuses (probably has a number of them for different control and probably on the outgoing terminals of the panel). then you only need the signal back to the relevant input. If you have the drawings I suggest you identify the card and see what the wire number is for the 110v supply.