Does anyone know if I can control two single solenoids with one relay on the cRio?
I know there are 8 channels so it seems that i should be able to. i tried it but it seems only one respondss?
thanks
Yes, you can.
Make sure you have a red wire connected to the control/power of the solenoid, and a black wire connected to the common/ground.
Power a Spike from a 20A circuit breaker on the Power Distribution board. Connect the first solenoid’s red wire to M+ on the Spike. Connect the second solenoid’s red wire to M-. Connect both black wires to the GND pin of the Spike (where they will find a path back to the PDB).
To turn both solenoids off, set the spike OFF.
To turn the first solenoid on, set the spike FWD.
To turn the second solenoid on, set the spike REV.
To turn both solenoids on, set the spike ON.
Alan has described the wiring for this rule.
<R42> Each power-regulating device (speed controller or relay module) shall control one and only one electrical load (motor, actuator or compressor).
Exception: Multiple low-load, pneumatic solenoid valves may be connected to a single relay module. This would allow one relay module to drive multiple pneumatic actions. No other electrical load can be connected to a relay module used in this manner.
The specification on the NI 9472 module is 0.75 amps per output or 6 amps total for the module. If you are looking to just feed two solenoids in parallel from one output and the total current is less than 0.75 amps then that meets specifications. Be prepared to document this should an inspector ask.
May I ask why you are doing this? I know it will work and all, but why not use the Solenoid breakout for the cRIO?
I’m sure there is a good reason, but I’m just curious.
I think you misunderstood, I am powering the solenoids via the relay ON the cRio. I am not using any spikes. I am simply wiring the solenoid to the relay on the cRio. I notice that according to the spec sheet you can run up to 8 solenoids off the relay on the cRio. does that make sense?
thanks
No, it doesn’t make sense. The only relay I know of that is allowed to control a solenoid on an FRC robot is a Spike. The NI 9472 Digital Output module with a Solenoid Breakout may also be used instead of a relay.
I am not aware of any relays on the cRIO.
@Alan et al: I believe the OP is mistakenly referring to the NI 9472 module as a “relay”. The part I’m not understanding here is the question. If you have wired one solenoid to the SOLENOID BREAKOUT module, which plugs into the connector on the NI 9472, why are you having difficulties wiring a second?
There are 8 ports on the Breakout, and you simply wire them to your solenoids, and write some code to turn them on and off at the appropriate times?
EDIT: Side note, the OP is listed as having association only with an FTC team. Is this correct or just out of date. This could explain why they’re having difficulty with FRC gear.
I interpret his question to be asking if two solenoids can be connected to a single Solenoid Breakout pin (so they’d act in concert).
I have to go review the 2011 rules to answer with some supporting evidence.
(Blackberry’s don’t easily lend themselves to that kind of search.)
If the cyllinders are activated at the same time, then another option is to use 1 solenoid with 2 Cyllinders via T-connectors after the solenoid. We do this for our cyllinders that activate shift our shifting transmissions.
I have not seen in the rules or in FIRSTs or NIs documentation where the solenoid breakout or NI 9472 is called a relay. That leads me to beleive that <R42> does not apply to the solenoid breakout, even though I agree that the NI 9472 can probably handle it.
It seems like a reasonable question for Q/A.
So get a Droid!
<R60> doesn’t limit the number of devices connected to each Solenoid Breakout output. If you really want to connect multiple pneumatic solenoid valves to a single output, there doesn’t seem to be a rule against it.
<R60> Solenoid Breakout outputs shall be connected to pneumatic valve solenoids or photoelectric sensors, PN 42EF-D1MNAK-A2, only. No other devices shall be connected to these outputs.
But I’d really like to know what John (johncap100) is planning. There are probably better and/or easier ways to do it.
The NI 9472 is printed to look like a relay on the side of the module. The current limitations of the module would allow two low load solenoids to be connected to each output under the rules. That is the load of two solenoids must not exceed 0.75 amps. Since there is eight outputs, that is 6 amps total for the entire module.
This rule also applies.
<R42> Each power-regulating device (speed controller or relay module) shall control one and only one electrical load (motor, actuator or compressor).
Exception: Multiple low-load, pneumatic solenoid valves may be connected to a single relay module. This would allow one relay module to drive multiple pneumatic actions. No other electrical load can be connected to a relay module used in this manner.
No, the NI 9472 is printed to look like a simple SPST switch. So is the photosensor, and that’s not a relay either.
That makes it sound like two solenoids is the limit. Do you just mean to say that the total load of all solenoids must be less than or equal to the 0.75 A capability of the output?
How does <R42> apply? The NI 9472 is neither a speed controller nor a relay module.
this is informative. i had a question though, does any one have a diagram that i can use to wire a spike realy? tonite is the nite that my team stops work on the frame, and starts wiring, and arm building, as well as minibot design. any advice on any of these subjects will be welcome
Links to the IFI documents can be found on the First KOP page or by going directly to the IFI (Innovation First, Inc.) website.
wow lots of good discussion, I did mean the solenoid breakout, i simply used the word relay because that is what is printed on the side of the breakout. I did get it working. As it turned out i had a single space on the ref name, so the second solenoid was not being read.
I do understand now that the spike is called a relay and the breakout is not called a relay. But understand my confusion when right on the breakout it is labeled a relay.
thanks again for all the discussion
Glad you are in business. Good Luck.