Getting five wire stepper idle valve working with Emerald K3
Discussion
Does anyone have any experience of making this happen? I am using the latest K3 ECU andd have all the right options checked, have tested continuity down the loom to the idle motor but no sign of life from the idle motor at all. in the live adjustments screen I can go from idle position 1 to 100 on manual control and there is no movement or vibration from the motor at all. Have bench tested the motor and it works smoothly over its full travel (shorting out one pin at a time). As usual, Emerald haven't responded to any of my emails on the subject so I thought I might get some help here!
Many thanks
Adam
Many thanks
Adam
Just to add a little more detail to post above: The Emerald K3 has four terminals that control the stepper motor, and in the software as you're setting it up it specifies a "five wire unipolar stepper motor". Am I right in thinking that it should ground these four terminals in one order to open the motor, and the reverse order to close the motor?
The toyota stepper motor that I'm using has six wires going to it, two live and four grounds that are to be operated in sequence. On the circuit diagrams for it, it shows each positive goes to the middle of a coil, there are two coils which are shown as being at right angles to each other. The four grounds go to either end of the two coils. I don't think this is a unipolar arrangement, as the emerald ecu mentions, but the method of operation is exactly the same: ground the four coils in the right order, one at a time, and the motor opens and closes depending on the sequence.
So as long as the coils are wired to the emerald in the correct order it should work!
The trouble is, there is no definite data about which order the emerald grounds these terminals, or if it grounds them at all in fact! It calls the four terminals 1,2,3 and 4 in the manual, and I've got it wired so that grounding them sequentially will open the motor, grounding them 4,3,2,1 will close the motor. The motor is doing absolutely nothing at the moment, no clicking or humming or any sign of anything.
The toyota stepper motor that I'm using has six wires going to it, two live and four grounds that are to be operated in sequence. On the circuit diagrams for it, it shows each positive goes to the middle of a coil, there are two coils which are shown as being at right angles to each other. The four grounds go to either end of the two coils. I don't think this is a unipolar arrangement, as the emerald ecu mentions, but the method of operation is exactly the same: ground the four coils in the right order, one at a time, and the motor opens and closes depending on the sequence.
So as long as the coils are wired to the emerald in the correct order it should work!
The trouble is, there is no definite data about which order the emerald grounds these terminals, or if it grounds them at all in fact! It calls the four terminals 1,2,3 and 4 in the manual, and I've got it wired so that grounding them sequentially will open the motor, grounding them 4,3,2,1 will close the motor. The motor is doing absolutely nothing at the moment, no clicking or humming or any sign of anything.
I've tried putting a multimeter on one of the 4 ouput terminals from the ECU. No sign of it going to ground as I press the buttons on the laptop that should move the ECU. I don't know how long each output would pulse for and whether I'd expect to see a shift on a digital multimeter though. Is it likely that the ECU grounds the pins for a second each time, or a tenth of a second, or what?
I don't have any idea what that driver is trying to do. Hopefully the installation instructions will tell you what the output is intended to do i.e. whether it is trying to pull up or pull down. Since it has to be sustained for long enough for the motor to physically move it should hold the output for at least a few tens of milliseconds but maybe not enough to see on a slow digital multimeter. I'd try using the meter to see whether each terminal is providing earth, power or floating in the 'rest' condition and then use a test lamp to see whether any of them change when you try to move the stepper. I've no experience getting this working but just on general principle I'd expect to see each output go 'active' in turn to nudge the stepper along i.e. at least one of the outputs should be active at any given time.
Edited by GreenV8S on Saturday 9th February 15:02
After doing some more digging on the web, my Toyota stepper motor IS a unipolar stepper, just as the ECU is expecting. The only difference between five wire and six wire is that the two power leads (one for each pair of coils) are commoned inside the stepper motor assembly on a five wire, as opposed to having two seperate input terminals on a six wire. I've also read that this set-up is pretty much universally used for idle motors so it should tie-in with what the emerald is set up to control.
Good idea about using a test light rather than my digital multimeter, can I use a 12V LED for this or is that going to be too slow to react compared to a filament bulb?
My other option is swithcing to a two-wire PWM-type idle motor, but if it says it can run a stepper in the manual I want to exhaust every possibility before paying out for a new idle motor and spending time making it fit.
The lack of support from Emerald is really frustrating; I have read good things about them in the past, but I have sent four to-the-point emails asking questions which SHOULD be answered in the manuals, and had no response. If I ring up, I can only speak to the secretary there, who tells me to send an email . . . !
Good idea about using a test light rather than my digital multimeter, can I use a 12V LED for this or is that going to be too slow to react compared to a filament bulb?
My other option is swithcing to a two-wire PWM-type idle motor, but if it says it can run a stepper in the manual I want to exhaust every possibility before paying out for a new idle motor and spending time making it fit.
The lack of support from Emerald is really frustrating; I have read good things about them in the past, but I have sent four to-the-point emails asking questions which SHOULD be answered in the manuals, and had no response. If I ring up, I can only speak to the secretary there, who tells me to send an email . . . !
An LED is excellent for spotting fast changing signals, it responds much faster than an incandescent bulb. This is particularly useful if the signal has a very low duty cycle and you are trying to spot very short pulses which might not be visible at all with a bulb. The main disadvantage is that they are polarity sensitive so you have to connect them up right rather than just bung them on and see what happens.
Edited by GreenV8S on Saturday 9th February 17:01
I spent a bit of time on this this morning. I double checked my wiring and I have continuity between the four terminals of the ECU and the correct four terminals in the idle valve multiplug. At rest, the four control terminals have no continuity to live or to earth. I connected my LED between one of the idle valve terminals and the battery +ve, pressed the keyboard buttons to order the motor to move, and there was not even a hint of a flicker from the LED. I also reversed my test lamp wiring to see if the control wires were going to +ve rather than to ground, still nothing. They don't seem to be doing anything!
Fester - thanks for the tip, I will try and get hold of Dave in the week.
Fester - thanks for the tip, I will try and get hold of Dave in the week.
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