defcon.klaxon
Lifetime Supporting Member
Hi all,
To make a long and annoying story short, a client has two flowmeters in their water plant and the flowmeter that controls the CL2 dosage pumps stopped working. They have a second flowmeter that is local readout only, so they asked me to make the system run on that one instead. Unfortunately the Seametrics FT450 does not have 4-20mA outputs, only pulses.
First off, their system of K-factor and Set P for setting up the pulse output is utterly confusing, I don't see how they relate and their tech support was not exactly helpful. If anyone has experience with these, please let me know.
Second, I'm amazed that the pulse output is maxed at 6.5Hz; not kHz, Hz. Unfortunately the PLC I'm working with is an ICLinks Everest and it does have a spare digital input with high speed counting, but it's meant for *high speed* and the Rate measurement tag is an integer. So my concern is that the resolution is going to be absolute garbage. I'm working with ICLinks tech support but I don't have a good feeling about making this work, from what I've read thus far.
That all being said, is there some sort of device that'll take such a low max freq pulse and create a 4-20mA signal out of it? Unfortunately the client is a tiny, tiny rural system and they have very little money; the notion of replacing the transmitter unit with a 4-20mA capable unit is likely going to make them cringe, even though it's clearly the easiest and most straightforward solution.
Thanks guys!
To make a long and annoying story short, a client has two flowmeters in their water plant and the flowmeter that controls the CL2 dosage pumps stopped working. They have a second flowmeter that is local readout only, so they asked me to make the system run on that one instead. Unfortunately the Seametrics FT450 does not have 4-20mA outputs, only pulses.
First off, their system of K-factor and Set P for setting up the pulse output is utterly confusing, I don't see how they relate and their tech support was not exactly helpful. If anyone has experience with these, please let me know.
Second, I'm amazed that the pulse output is maxed at 6.5Hz; not kHz, Hz. Unfortunately the PLC I'm working with is an ICLinks Everest and it does have a spare digital input with high speed counting, but it's meant for *high speed* and the Rate measurement tag is an integer. So my concern is that the resolution is going to be absolute garbage. I'm working with ICLinks tech support but I don't have a good feeling about making this work, from what I've read thus far.
That all being said, is there some sort of device that'll take such a low max freq pulse and create a 4-20mA signal out of it? Unfortunately the client is a tiny, tiny rural system and they have very little money; the notion of replacing the transmitter unit with a 4-20mA capable unit is likely going to make them cringe, even though it's clearly the easiest and most straightforward solution.
Thanks guys!
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