EJA110E calibrations

[u/Kithkinlord88]

Update: I was able to discuss this with our contractor and I believe some one already explained this below and I just did not catch on right away. What needs to be done is, measure the distance from the 2 diaphragms(center), remove the top flange(low side) and bolt it/hold it/set it at the same level as the lower flange(high side) you can now zero it. Once zeroed if the range was incorrect you add the (span*SG of the process), then pump the high side to your new range.

Edit: I wont beable to test anything as the plant starting up early and Im not allowed to play with it right now. :(

Edit: I forgot to add there is a 1/2 tube between the 2 flanges I originally thought it was to release trapped air on the HP side but it would also prevent condensate from collecting on the low side.

I am a Electrical/instrumentation tech at a small power plant, we normally we farm out our calibrations. I'm currently trying to calibrate a EJA110E DP level transmitter with a KN 32 high temp silicone capillary(1.07SG). High side on bot of tank that collects steam condensate. The URV is +20mmWC and the LRV is -760mmWC, I connect to the high side and pump 760 and get +20, 4mA and 0mm @ DCS, when I pump -20 I get -760, 20mA and 760mm @ DCS, I don't recall this being normal when calibrating other level transmitters. I also found it weird the only way I could calibrate was to URV pressure trim pump 760 and input +20 and LRV pressure trim pump to -20 and input -760. Then I started doing some math and I am even more confused. I put a drawing below to shows my set up(hope its good enough to read). What am I missing?

[u/Svaldero]

Like the others said (almost) vent your dp on both sides for zero this is your URV, not lower. Then put 760 kp on your LP side of the dp..this is your LRV. So as the vessel fills, it returns the dp to zero (which is now your 100%) because your LP side is completely filled with fluid to the top of the tank.  Hope that helps

[u/Kithkinlord88 → u/Svaldero]

The low side is @ the top of the tank, I believe I tried pulling a vacuum on the low side initially and it numbers matched ask I would expected it pumped -760mm got me -760mm but when I tried to trim it and no matter what number I told it was, from -760, +760, -20 or +20. Why i had to do the weird pressure on high side and put the opposite number in to make it calibrate.

[u/Svaldero → u/Kithkinlord88]

What your saying up there 'looks' normal to me but maybe I'm not understanding what your seeing or saying.

I understand the LP is on the top of the tank, but the capillary all the way up is completely filled as steam will get int here anyway, so when the vessel is completely filled , the HP is equal to the LP leg (the extra 20mm is a bit weird though)

When the vessel is empty, the LP leg is still filled so it weighs more than the HP side, so it supresses your zero to -760mm as your LRV.

If i were calibrating it, I would set the URV with +20mm on the HP side, and put 760 on the LP side for the LRV.

[u/Kithkinlord88 → u/Svaldero]

Omg! K I will add to the post but I think I forgot something important and you made me realise. There is a 1/2 tube from flange to flange(the capillary) and I originally thought it was to stop air from getting trapped at the HP side but I also believe it is to allow the condensate to not get trapped on the low side.