caradis Posted January 3, 2020 Share Posted January 3, 2020 I think this is the right spot for this, but if not let me know. So, im having some porblems with wiring in some relays. i have some DIY ABC modules wired in to the ends of the loops on my fiddle yard. the whole idea being the routes are automaticly set via JMRI, the points switch automaticly and the blocked lines have ABC activated towards the end of the loop to stop any incoming trains. to do this the ABC modules are switched on and off via Dcc imputs from an ArCoMoRa mardec. the imput from the mardec switches is supposed to switch the relay between ABC and ABC bypass, however i get no switching on the imput from the Mardec. there is a minor dimming of the onboard LED (Relay) with the signal, , but being no electronics expert, im not sure if ive wired this correctly, or not, any help appreciated Link to post Share on other sites More sharing options...
Nigelcliffe Posted January 4, 2020 Share Posted January 4, 2020 To offer any help need (a) a diagram of what you think you've done, and (b ) specification of the devices used - such as the "relay" and how they are powered. I suspect it may be a mis-match of voltages. Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 attached is a picture of the relay unit. the wires in to the screw terminals are the NC common and No terminals with the dcc/ track voltage bottom corner has (from top to bottom) 12vDC gnd, input1-4, 12vDC VCC then 12vDC JDVCC Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 (edited) Hi The pair of pins marked VCC / JD-VCC should only have a push on jumper connection. If that is missing, remove blue wire and link the two pins by soldering a piece of wire across them. VCC is Positive and it looks as though your Blue wire is possibly a Negative? To note Pins along the bottom are GND = Negative. IN-1 through to IN-4 are also Negative. VCC is Positive DC. Below is a picture of mine unused at this stage. Just found a wiring drawing for these here... Link to click Edited January 4, 2020 by Brian Link added Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 (edited) yes, the red is 12v+ and the blue 12v- i should point out that the imput from the mardec is ~4-6vDC,. seems to be fairly constant Edited January 4, 2020 by caradis Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 (edited) You need to remove the blue wire on the two right hand pins marked VCC/JD-VCC and just link these two pins with a piece of soldered on wire or use the push on connector. Next you will need to provide a 12 volt DC power source to the front row pins VCC (Positive) and GND (Negative) . The four pins IN-1 to IN-4 need a negative supply to them that is the same as the GND source. This can be from the same power supply or two separate ones with the two Negatives of the differing supplies linked together. Note I'm not familiar with and unsure of where you're Mardec power is derived from and is it suitable for common negative connections?? Will try and do some research on these Mardec units. Edited January 4, 2020 by Brian Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 https://www.arcomora.com/mardec/ thanks for the responses, this is the site for the mardecs, essentially a cheap accessory decoder. ive just had a try with the 12v negative supply on to one of the IN pins, no joy, the LED lights up when i touch the wire to the contact, but no switching of the relay Link to post Share on other sites More sharing options...
jpendle Posted January 4, 2020 Share Posted January 4, 2020 So the IN pins need to be driven to 0 volts (GND) to switch the relay on and 5V to switch it off. The Mardec will do this quite happily. BUT the GND of the Mardec MUST be connected to the GND on the relay board for this to work. Regards, John P Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 can anyone provide a labled wiring diagram for what should be going where? ive tried the last few suggestions but as of yet ive had no joy Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 (edited) Hi Why not try the relay board on its own first to ensure its actually working? I have had two four way ones where the opto isolator has failed preventing that relay from energising! I would ensure 12 volts DC is applied to just the GND and VCC front row pins. GND being Negative or 0 volts. Then take a short length of wire and connect one end to the GND pin or somewhere else that the negative (0) volts is coming from. Touching the other end of the wire in turn onto pins IN-1 to IN-4 should cause each relay to energise in turn and its appropriate LED to light as each IN pin is sent to negative zero volts. You of course also need the right hand pair of pins linked and no wires on them. See pics below of my 12 volt relay board being feed from 12v DC and a negative on IN-1 then on IN-2 Edited January 4, 2020 by Brian Photos added Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 right, so as suggested, the board is sitting with only gnd connected to 12vDC- and VCC connected to 12vDC+ (jumper is on between JDvcc and vcc) using a wire connected to the same 12vDC- source i touch the IN pins and get the LED coming on. measuring for contact between the NC and common they are in constant contact. would this suggest that somehting has broken? Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 (edited) Hi Can you hear the relay pick and drop with the negative lead being touched on the IN pin? Is there a circuit between Com and N/C contact (Middle and left terminals) when no power is applied. If so, does this short get removed when the relay energises? Middle of the three is Com to the outer pair of the three contact tabs So middle of three to left makes connection when the relay is not energised. Middle to right makes connection when relay is energised. When relay is energised the middle to left is opened. - These are the rear group of terminals looking down on the board with these contact terminals at the rear of the board. Also what happens on the other three relays when they are energised in turn? Other than that I suggest you look carefully at the underside for missing or poor soldering. Edited January 4, 2020 by Brian Contact info updated Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 HI no, no noise what so ever when the relay in energized. there is a circuit between middle and left (com and NC) which is consistent, even on connecting the power to the IN pin. the same happens on the other three relays as well, COM to NC stays in contact and doesnt change when power is applied. the solder contact of the board look fine Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 (edited) Sorry to ask again.... Have you linked the pair of pins on the right marked VCC / JD-VCC? Unless these are linked nothing will work. Next, does each LED light when negative is connected to each IN Pin? At the time each of the IN pins is connected to 0 volts (Negative) the LED for that IN pin and the relay should be heard to click as it energises (picks). Dabbing the wire On then Off of each IN pin should cause each relay in turn to energise and de-energise and an audible click should be heard as the appropriate relay energises / de-energises (picks and drops). Edited January 4, 2020 by Brian Text updated Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 yeah, jumper os on between VCC/ JD-VCC yes, each LED lights when i connect the signal wire, but there is no click, nor doe the circuit between com and NC break. this is the same on all 4 Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 (edited) Reads as though all the Opto isolators or the transistors have failed? Or there is some common connection problem on the PCB somewhere. The main common connection is the two pins VCC / JD-VCC So its worth checking the two pins VCC/JD-VCC where they are soldered to the PCB. As one (or both) of these connections may have become high resistance due to the soldering of wires onto the pins? I assume you're using a good 12 volt DC power source? Edited January 4, 2020 by Brian Text updated Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 having just checked, there is deffinetly a circuit between both pins and the Vcc on the row of 6 pins i cant see anything on either side of the board to suggest a connection problem. Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 I fear you may have blown all the transistors or the Opto Isolators due to connecting a negative to the VCC/JD-VCC pins! These 12 volt 4 way relay boards are not that expensive and can be obtained from China for about £2.70 each - Banggood sell them Banggood link post paid. If you want, I can take a look at the board, but the postage really may out weight the replacement costs. If you want to send it to me P.M. me. Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 hmm, thats unfortunate. ive got an 8 way board coming on monday, so how should i wire that one in? Vcc to 12vDC+ GND to 12vDC- or should they be connected to the 5vDC +/- terminals on the Mardec? or 12vDC+ and mardec - ? thanks for the offer but ill just get another from Ebay, itll probably work out quicker Link to post Share on other sites More sharing options...
Brian Posted January 4, 2020 Share Posted January 4, 2020 Hi If the relays are 12 volt rated then they need to have 12 volts DC to feed them! If they were 5 volt rated then the supply VCC supply has to be 5 volts DC! The GND volts (0V / Negative) has to be shared/commoned with the the unit that supplies the output negative (0V/GND) to the relay boards IN pins. When your new relay board arrives and assuming the relays are 12 volt rated, then test it as before, before wiring it to the mardec. Do this by linking across pins marked VCC to JD-VCC (Usually has a push on link fitted anyway). Apply 12v positive to the VCC front row pin and negative/Ov to the GND pin. Also connect the test wire to GND and then dab On/Off onto each IN pin in turn to ensure the whole board works correctly. Ensure this wire can't touch the Vcc connection. Only then once relay board is proved correct connect each output terminal of the Mardec to the appropriate IN- pin on the relay board needed,. But the output negative of the Mardec and the relay board need to be connected together. This is where I'm not 100% sure it is OK to do this on the Mardec? Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 ok, thanks for the advice. the mardec has auxiliary pins for these functions, and claims to be able to do these things, so should be fine. Link to post Share on other sites More sharing options...
Nigelcliffe Posted January 4, 2020 Share Posted January 4, 2020 Given that the Mardec decoder is, essentially, an Arduino processor, it might be simpler to use a 5v version of these relay boards, rather than the 12v versions. The Mardec documentation has a diagram on the last page suggesting how to connect things up. It uses a separate 5v regulator for the relay coils (a cheap device, can be bought pre-assembled, such as a LM317 adjustable voltage unit). If sticking with 12v, I think that's OK using what Brian has indicated. I suggest buying some "dupont" connectors, which will push-fit onto the tags on the relay boards, rather than soldering stuff. If you buy double-ended ones, attached to ribbon cable, tear off enough ribbon for the number required, cut in half, and use the "wire" end into terminal blocks. Most of the connectors will glue into "blocks" with plasticard solvents, and can glue a strip of plasticard along a "block" to make it larger/easier to hold, identify orientation, etc... There's a certain amount of "you're buying a DIY Arduino circuit" in the Mardec stuff, so reading up on how to connect things to Arduinos might be the way forwards. There are a lot of beginner guides to Arduino available. Link to post Share on other sites More sharing options...
jpendle Posted January 4, 2020 Share Posted January 4, 2020 You keep referring to 12VDC- being connected to GND. if this is truly -12VDC then you are connecting 24V to the board NOT 12v. You should connect +12VDC to the VCC pin and 0V to GND. Regards, John P Link to post Share on other sites More sharing options...
caradis Posted January 4, 2020 Author Share Posted January 4, 2020 yeah , do mean the 0v output of the 12vDC outout, im not really electricaly minded, so noting it down like that is easier for me if not correct. Link to post Share on other sites More sharing options...
Brian Posted January 5, 2020 Share Posted January 5, 2020 (edited) The problem is with the terminology, and I'm not going to confuse the situation if possible , but you are probably (along with most other users) using a simple DC power source which provides a Positive and Negative supply This could be a battery or mains to low voltage power supply offering the DC output required. So in your case VCC is Positive and on the relay board GND will be connected to your supply Negative. But many electronic items will reference 0v. GND is not normally connected to a physical Earth. Many wiring drawings will have simple + or - markings for their connections to the supply. There, a battery or power source is fairly obviously connected as marked, Positive to +v and Negative to -v. Electronics as I stated likes to use VCC and and normally 0v as the two reference connections. Again VCC is positive to the 0v However, some circuits require the power to be split into three distinct pieces +v, 0v and -v. A very simple idea of this would be to connect two 9 volt PP3 batteries together is series so the - terminal of one joins to + of the other battery and a centre tap wire comes from that joining +/- connection. This then would give three connections of +9v on one battery terminal, 0V on the centre tap between the two batteries and -9v on the negative terminal of the other battery. This is where the -v comes from. But this is not what you're after and you really don't need to worry too much about this. Edited January 5, 2020 by Brian Spelling corrected 1 Link to post Share on other sites More sharing options...
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