Issues with SEN0264
Account cancelled 2019-10-02 12:23:12 2884 Views1 Replies G'Day community.
I purchased 3 x SEN0264 for testing in an application for a customer of mine as they looked well spec'd with a standard 4-20mA output to suit industrial electronics.
I've had the first 2 units fail within days of installing and we're getting no help from the Core Electronics in Australia who we bought the sensors from.
The sensors perform as expected for about 48 hours, then the first one failed with < 1mA output. Power cycling and changing ground made no difference. Thought that something might have gone wrong with the install or treatment/care of the sensor, so we checked over the machine for ground issues, difference in ground potentials and so on. Nothing. Removed the sensor and used a Fluke 772 to loop power it, still dead.
We bench tested the second sensor before installing for a couple of 30 minute periods. 30 minutes is the limit on the fluke meters before they turn off if you're not pressing buttons to save battery. Sensor looked OK. Checked over the machine again, and tested the field controller (Shinko temp controller) with the loop calibrators before installing the sensor. All performed as expected. Put the second sensor in and found the case on it was not connected to the shield on the fly lead/cable. So we insulated the SEN0264 from the metal frame of the machine and it read the expected numbers. It worked for 2 days with nothing running, then it malfunctioned.
The malfunction was increase in current from 7.35mA for ambient up to 9.35mA with no change in ambient temp or installation of the sensor. Checked for differences in ground potential etc. - nothing. So we removed the sensor and bench tested. Sensor was fine. Put the sensor back, but this time removed the insulation from the frame of the machine, and it worked fine for about 24 hours.
Now the sensor only produces > 20mA output, even when completely isolated and loop powered by one of the Fluke calibrators.
It's a temperature and humidity controlled food factory - constant 20 degrees and 35% or lower RH 24/7, no condensate and not installed in a wash down area.
Even though there was no measurable ground potential difference, we grounded the machine frame to the power supply frame, grounded the sensor and grounded the shield on the sensor. What was odd is that every time we grounded the shield on the sensor cable, with the sensor grounded by case to machine frame or not, the sensor would malfunction within a minute and sharply step up by 2mA. We went from the sensor malfunctioning if it was grounded to the machine frame, to the sensor malfunctioning if the shield was attached and the frame grounded... but the sensor only working if the case/frame was grounded to the machine and the shield lifted.
It'd be a bit nuts to throw the 3rd sensor in with the previous 2 failures, so we bench tested it without installing. Seems fine - but so did the other 2.
Anyone else have any experience with this sensor? Where did you use it, how was it installed etc.
I purchased 3 x SEN0264 for testing in an application for a customer of mine as they looked well spec'd with a standard 4-20mA output to suit industrial electronics.
I've had the first 2 units fail within days of installing and we're getting no help from the Core Electronics in Australia who we bought the sensors from.
The sensors perform as expected for about 48 hours, then the first one failed with < 1mA output. Power cycling and changing ground made no difference. Thought that something might have gone wrong with the install or treatment/care of the sensor, so we checked over the machine for ground issues, difference in ground potentials and so on. Nothing. Removed the sensor and used a Fluke 772 to loop power it, still dead.
We bench tested the second sensor before installing for a couple of 30 minute periods. 30 minutes is the limit on the fluke meters before they turn off if you're not pressing buttons to save battery. Sensor looked OK. Checked over the machine again, and tested the field controller (Shinko temp controller) with the loop calibrators before installing the sensor. All performed as expected. Put the second sensor in and found the case on it was not connected to the shield on the fly lead/cable. So we insulated the SEN0264 from the metal frame of the machine and it read the expected numbers. It worked for 2 days with nothing running, then it malfunctioned.
The malfunction was increase in current from 7.35mA for ambient up to 9.35mA with no change in ambient temp or installation of the sensor. Checked for differences in ground potential etc. - nothing. So we removed the sensor and bench tested. Sensor was fine. Put the sensor back, but this time removed the insulation from the frame of the machine, and it worked fine for about 24 hours.
Now the sensor only produces > 20mA output, even when completely isolated and loop powered by one of the Fluke calibrators.
It's a temperature and humidity controlled food factory - constant 20 degrees and 35% or lower RH 24/7, no condensate and not installed in a wash down area.
Even though there was no measurable ground potential difference, we grounded the machine frame to the power supply frame, grounded the sensor and grounded the shield on the sensor. What was odd is that every time we grounded the shield on the sensor cable, with the sensor grounded by case to machine frame or not, the sensor would malfunction within a minute and sharply step up by 2mA. We went from the sensor malfunctioning if it was grounded to the machine frame, to the sensor malfunctioning if the shield was attached and the frame grounded... but the sensor only working if the case/frame was grounded to the machine and the shield lifted.
It'd be a bit nuts to throw the 3rd sensor in with the previous 2 failures, so we bench tested it without installing. Seems fine - but so did the other 2.
Anyone else have any experience with this sensor? Where did you use it, how was it installed etc.
