David Coles
Member
Hi there
have recently installed some Flex IO to replace some Solartron IMPS and an old style Emerson Scanner. But I am having issues with some of the temperature readings from the IR8 module installed. There is also an IF4I module installed but the signals from this are perfectly ok.
The old set up was a scanner that monitored the RTD's and generated a 4-20mA output that was then dropped across a resistor to give 0.4 to 2V for the Solartron IMP to monitor. This worked perfectly well with no issues. Because of obsolescence we are gradually removing the IMPS.
However, on a few of the installations where we have an IR8 installed we are getting unstable readings. For much of the time they will read perfectly ok but then start to oscillate before stabilising again. I am unable to identify any plant side triggers for this. Does any one have any ideas on this?
I realise the IR8 channels are not isolated and so am guessing something is possibly providing a path to earth that ends up affecting the circutis but am not sure of this. Have attached an image of the oscillation.
have recently installed some Flex IO to replace some Solartron IMPS and an old style Emerson Scanner. But I am having issues with some of the temperature readings from the IR8 module installed. There is also an IF4I module installed but the signals from this are perfectly ok.
The old set up was a scanner that monitored the RTD's and generated a 4-20mA output that was then dropped across a resistor to give 0.4 to 2V for the Solartron IMP to monitor. This worked perfectly well with no issues. Because of obsolescence we are gradually removing the IMPS.
However, on a few of the installations where we have an IR8 installed we are getting unstable readings. For much of the time they will read perfectly ok but then start to oscillate before stabilising again. I am unable to identify any plant side triggers for this. Does any one have any ideas on this?
I realise the IR8 channels are not isolated and so am guessing something is possibly providing a path to earth that ends up affecting the circutis but am not sure of this. Have attached an image of the oscillation.
