In this lesson I am going to show you how to rearrange a pressure transmitter
from 0-10 bar to 0-5 bar using the following test equipment. We have a
Druck DPI 610 IS that we are going to use as our calibrated pressure application.
We have the pressure transmitter itself which is a Foxborough IG10P. We have a fluke 789 process
meter that we're going to use to power the transmitter and also read back its milliamps.
We have a HART 475 field communicator that we're going to use to connect to the transmitter
to change its range and settings. All I have done here with the transmitter is remove the back plate,
which is here, which is where we would normally have our process connections, we would have entry
through this 20 millimetre electrical port in with a gland, but here I've just got two cables connected
which i'm going to use to connect to my fluke 789 meter. I need a process connection from the
pressure transmitter to the Druck DPI. The pressure transmitter has a half inch NPT male thread,
were as our test equipment has a Gyrolok quarter inch connection. I have my fitting adapter which
has a half inch male NPT thread which will allow me to attach my quarter inch Gyrolok fitting.
In order to attach the two and make sure that we have a good seal, we're just relying on the NPT threads
to seal against the female NPT threads on this connection.
In order to make sure we've got a good fit, we're going to apply some PTFE tape
to prevent any leaks. Here we have some PTFE tape for application onto an NPT connection port.
I'm just going to give a couple of wraps around the connection part on our transmitter.
That will help us have a leak free connection. Next I can take my adapter
and wind this on up. Then, just using two adjustable Bacho shifters, tighten up this connection
to make sure we've got a good seal. This is just a Gyrolok small bore tube fitting on
some nylon tubing, the actual seal is made by the olive into the base of the fitting.
Screw that onto the transmitter base making sure we have a reasonable tight connection.
I'm also going to check the connection on the truck is tight, and that seems quite tight.
We'll be rearranging this transmitter which is currently range from 0 - 10 bar
to 0-5 bar so I want to make sure I've got stable readings around the 5 bar mark.
This DPI is currently ranged for up to 20 bar so it should do as our job. I'mgoing to power up
the drop DPI, this will take a moment, here we can see we're currently reading 0.001 bar.
We're now going to make sure the vent is closed which is this part here
and i'm just going to start pumping up and make sure we're not losing
pressure, all we're doing is pressurizing from here through into our transmitter.
This looks okay, it looks quite stable already 1.2 bar, I'm going to carry on pumping up,
It will take quite a while with air. For higher pressures you would want a hydraulic pump.
There we go 5 bar but we'll now leave that for a minute or so just to make sure that we're
holding pressure. As you can see the pressure is falling down fairly slowly and we've got
a seal which is going to be good enough for us to carry out our calibration. I'm now happy with the
pressure application on this meter. I'm now going to open the vent and allow the pressure to vent.
The next thing we need to do is power the transmitter, I could use the Druck DPI
to provide the loop power for the instrument, but I'm going to show you in this one how to do it
using the 789. Onto these process connections I've just wired in two pin crimped connections with a
short piece of wire that has fitting connections that will allow us to go into our meter.
The meter needs to be switched into milliamp loop power mode, it's important to note that
on the transmitter i've got the red connection going to the positive and the black connection
go into the negative. I'm now going to connect into my fluke 789 using the appropriate ports.
The appropriate ports are the loop power on this left hand side
goes to positive, and black goes to negative. We can see there that we're providing loop power
and we're reading 3.99 milliamps, which is what we would expect as this transmitter
is currently ranged 0-10 bar and the atmospheric pressure is approximately zero.
So 4 milliamps is what we would expect to read. The next thing we're going to do is connect
our heart communicator to the loop, which will allow us to make modifications to the range of
the instrument. This particular model has pins that allow us to go in and use the communicator. Then
power up the 475. The application will load on the 475, then toggle down and go on to online. Here we
can see we are talking to the I/A pressure and that is online. So we can see that we have currently
reading 0.004 bar which is around atmospheric. Its process value AO, which stands for analogue output,
is reading approximately four milliamps. Which is what we're reading on our fluke 789. Lower range
value is zero bar and the URV or upper range value is 10 bar. We want to change this to 0 - 5 bar.
To do that, we're going to go to device setup, going to go to calibrate.
We're going to go to PV rearrange. I'm going to edit the low range value and upper range value.
I'm going to go down to the upper range value and we're going to change this to 0 to 5 bar,
press enter. So you can see here the upper range value has a little star next to it, as you can see
there's a little star next to URV that means the changes have been made in the HART, but
not in the instrument, to do that we press the send button. It gives us a warning to say that this is
going to affect our outputs and press ok and we can now return the loop to auto control and the
URV is now reading 5 bar. We can now disconnect the HART and complete our calibration checks.
We just go back through the menu structure
and we want to exit the HART application. We can now power down the heart as we no longer
have to do any work with that. I'm just going to put it into standby mode, the heart powers down
and I can remove the connections from the HART. This is a five point calibration check sheet.
This is just one, this is a mock-up sheet I've made. We would normally have information such as
the transmitter tag the serial number but for this i'm just showing you how we check that the range
is what we hope for. We're currently applying zero bar so the applied pressure is zero bar expected
milliamp reading would be four milliamps which is the bottom end of this range. We're actually
reading three point nine nine one so there is a small error, a very acceptable error that, but
we will go on to see how much of that error that actually is after. So we go three point nine
nine one milliamps. Unfortunately the red pen is quite hard to read on here. So I'm going to use
a marker and just go over that. I'm going to do it to two decimal, places so 3.99
milliamps. So the error in milliamps is - 0.01 milliamps. Okay we're now going to
close the vent on the drop dpi and we're going to attempt to go to 1.25 bar applied. So start pumping
and to get the last fine adjustment we're actually going to use this fine adjust here. So
a good little tip is to go as close as you can just below, so you want to try and keep
the direction going up you don't want to go over the set point you don't want to go to, and then come
back down because that can affect hysteresis. We're just going to pump there nice and slow.
1.25 bar nearly got it straight away there. So just going to tweak that up,
there we go 1.25 bar 0.3 but we'll just give that a little bit of time to settle out i don't
know if you did notice but there is some filter on the transmitter which is making the reading
a little bit slow to react but there we go that's stabilized,
and that's a pretty good error. We'll just see if we can get that that little bit closer
down to exactly 1.25 bar which we've got and 0.99 is what we're reading again so two decimal places
so 7.99 and again that's minus 0.01. Okay we're going to go to 50 % of the range which is 2.5 bar.
Getting there now, it's pretty close just back that off that time a little bit.
too far.
Okay so there we go we've got 2.500 bar and we're reading 11.98.
so our error is now -0.02. okay we're going to 3.75 bar,
overshot that slightly but just going to back off on this
fine adjust. Let that settle out, see where we're at 3.75 bar we're reading 15.99 rounded up.
Which is back down to 0.01 and then we're going to go to 5 bar, 100 of the range.
Okay 5 bar. I've got 19.98 , is - 0.02.
Okay I can now vent that pressure off. Okay we'll just turn our equipment off
and then we can just work out the exact error as a percentage and that's our calibration check
completed, including the rearrange. So we'll just remove our probes to kill the 24 volts, turn our
meter off. Let's turn this off we would then remove the connections remove the electrical connections
and then that transmitter is ready to be used in the field and it's calibrated.
Okay this is our sheet so we've worked out the error in milliamps but in order to work out the
error as a percentage of the range we just need a calculator. We need to take the error which is
0.01, we then divide that by the full range of milliamps which is 4 to 20 so that's
16 milliamps. We then times that by 100 and that gives us a very small error percentage so
0.06 %. Okay so the only one that's slightly different is this one
which is 0.02 so we've got 0.02 divided by 16 and then we times that by 100
and that's our error which is 0.125, so if we go to two decimal places
that's 0.13 percent so we can just fill these in as well. 0.06
0.06 and 0.13. Okay I hope you've enjoyed the video you've now got a better idea of
how to do a calibration check and rearrange of an instrument using the test equipment i've shown you.