Yokogawa EJX110A Hydrostatic Installation Guide

Selecting a Transmitter & Calculating Your Range

Transmitters are rated in mmWG (Millimetres Water Gauge), indicating the pressure exerted by 1mm of water on the transmitter. For example, a 1m water tank requires a transmitter with a range of 0-1000mmWG. To calculate the correct range for other liquids, multiply the tank height (H dimension) by the liquid’s specific gravity (SG). For instance, for a 1m diesel tank, multiply the height (1000mm) by the SG (0.7) to get a range of 0-700mmWG.

Use a low range transmitter (EJX110A-JFS4G-924EB/SU22) for 0-500mmWG.
Use a medium range transmitter (EJX110A-JMS4G-924EB/SU22) for over 500mmWG.

Installation

Connect the transmitter to a tapping point near the bottom of the tank, as it only measures the liquid volume above it. You can connect directly to the tapping point or via pipework but ensure the pipework slopes downward without loops. Note that the ‘H1’ dimension (distance from the tapping point to the transmitter) must not exceed the ‘H’ dimension (tank height).

Finding Controls

Zero-Adjustment Screw: Located under a small metal plate on the transmitter’s right side. Use a screwdriver to loosen the cover.

Range-Setting Switch: Found beneath the display; unscrew the clear front cover to access.

Vent Plug: Located on the transmitter body. Loosen the nut at the tip to vent the liquid.

Commissioning Un-Configured Transmitters

If your transmitter isn’t pre-configured, follow these steps:

1. Power up your transmitter.
2. Open the vent screw on your transmitter.
3. Fill the tank to the minimum level (so that liquid is flowing from the vent screw) and tightened the screw to prevent further bleeding.
4. Unscrew the cap over the display to access the buttons and release the cap over the zero screw.
5. Press the range setting button. The screen should say ‘L Set’.
6. Adjust the zero-adjustment screw until the display reads ‘0%’. This sets the minimum range of your transmitter.
7. Press the range setting button The display should now read ‘H Set’.
8. Fill the tank to the top.
9. Adjust the zero-adjustment screw until the display reads ‘100%’. This sets the maximum range of your transmitter.
10. Press the range setting button one last time to return to normal operation – your transmitter is now configured to the range of your tank.
11. Re-attach the display and zero adjustment screw cover.

Commissioning Configured Transmitters

If your transmitter is pre-configured, perform a zero adjustment:

1. Power up the transmitter.
2. Open the vent screw on your transmitter.
3. Fill the tank to the minimum level (so that liquid is flowing from the vent screw) and tighten the plug to prevent further bleeding.
4. Unscrew the cap over the zero-adjustment
5. Adjust the zero-adjustment screw until the display reads 0%.
6. Re-attach the cover.