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Thanks for the quick response waross. I had considered a voltage drop affecting the stepper motor current directly, but not the driver itself - which makes more sense, as the 24 V supply would have to drop to less than 5 V before the driver runs out of headroom, but the driver itself may drop...

Hi All, We have a machine that includes a stepper-driven linear actuator that moves a large vertical load. Most of the time the system works as intended, but every once in a while the stepper will slip when the brakes are released, causing the load to drop uncontrolled. A ball screw is used...

Thanks for the reply Brian. Regarding your comment on ethernet cable, part of my recollection was that multiconductor cables have a different requirement than individual conductors. I also found in NFPA 79, section 12.6.3: "Conductors shall not be smaller than 18 AWG for control circuits within...

Hi All, I am reviewing functional safety requirements according to US and international standards. One question I have not been able to answer is whether there is a minimum allowed wire gauge for both single conductor and multiconductor cable scenarios. I vaguely recall being told years ago...

Hi Everyone, We are having trouble getting three-phase sold-state relays. These are used to power a resistive heater load - in some instances a single heater is across two of the phases, and in others three heaters are distributed across the phases. I was able to find a single-phase SSR that...

Power the 2nd lamp through an normally-closed contact of a relay, power the relay coil from a current switch sensing the 1st lamp. When the 1st lamp is running the current switch is closed, powering the relay and opening the NC contact. When the 1st lamp burns out the current switch opens...

Thanks for the quick response IR. Looks like that Keithley solution is close, but it looks like it does not offer any industrial comms protocols such as Ethernet/IP, Profinet, Modbus/TCP, etc. This needs to interface directly with an Allen-Bradley PLC.

Hello, I am looking for an analog input card or device that measures resistance, and interfaces with an Allen-Bradley PLC, preferably using Ethernet/IP. The measurement repetition rate should be less than 500ms or so, ideally less than 100ms. Resistance range is about 50-500Ω. We need 48...

I had this exact issue recently when the cable length was increased. Turned out to be the extra cable capacitance, which was causing the signal to not reach the required voltage thresholds (and probably messed with timing too). The reason putting a single LED in front of the other two chains...

Hello, We have just got wind that a sensor we use may require individual annual calibration certificates from DAkkS, the German accreditation agency, for use in that country. I have so far been unable to uncover whether this is required in all industrial use cases or only in certain industries...

Now those are some interesting ideas! Unfortunately VEBill's suggestion will not work. I am particularly intrigued by Waross's idea of the small resistor in series though, I think that may be worth pursuing. Also thank you for the clarification on fuse usage, that is very helpful and is indeed...

Thanks everyone. I understand a thermal fuse is an option, but a very difficult one to package in this application. We are searching for alternatives that can be remotely located. Waross, we have sufficient means of active protection, but this is for when that active protection fails. We do not...

Hello, We have a heater whose resistance increases substantially as it heats up, meaning its current draw decreases. If left on too long at full power (~8-12 s) it can get too hot and cause issues. Normally the heater is used in a PID loop to prevent this, but that cannot be counted on without...

Fair enough; I doubt OP was planning on one though! I'm not too familiar with these - I would suspect considerable care must be taken to avoid demagnetizing the PMs.

If the permanent magnets are strong enough to pull the metal from out of the ground, who or what is strong enough to pull the metal back off the magnets once it attaches? Consider that the latter requires vastly more force than the former!

Power is easy enough, but the one I always struggle with is current per phase... I think there's a √3 involved?

Thank you for the followups! I'm not sure I realized this... makes sense though! waross's definitions are helpful in this regard. I do have a test devised, and a BOM picked out to do so, but I am increasingly convinced this is probably not necessary. I think part of my paranoia is early on we...

I think I answered my question regarding the need for 120V on the AC line for a test, versus using a low voltage: while the current will be pulsed and harmonically rich, the voltage will be a pretty consistent 50/60 Hz sinusoidal wave with very little harmonics, so the electric field should not...

Thank you for the responses! To address each of your concerns: FreddyNurk and itsmoked: All cable outer insulations are rated 300V, as well as the connector. For the small area where the outer insulation is stripped back there will be a physical gap of about 2 inches. waross: Good point...

Hello, For a product we make we are looking into a single connector that provides RS-485 communications, 24VDC control power, and 120VAC heater power. The connector would be a Harting or Epic style connector (if you search "epic connector" the top images are representative). I am concerned with...