YOKOGAWA EJX110A

USER GUIDE – YOKOGAWA EJX110A

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Yokogawa EJX110A Differential Pressure Transmitter

Differential pressure transmitters are easily the most common transmitter used in industry, a range of process variables such as static gauge pressure, level and flow can easily be inferred from differential pressure.

There’s quite a lot of misconceptions as to the correct way to isolate and de-isolate these devices – get it wrong you could cause irreparable damage to the instrument and cause costly downtime.
First of all it’s essential to understand these devices measure a difference in pressure between the high (H) and low (L) connections. This difference in pressure is usually much lower than the difference between any one of these connections and atmosphere. For example, if 1000KPa is present on the High connection and 950KPa on the Low connection you have a differential pressure of 50KPa. This differential pressure is most likely within the measuring range of the instrument. However, not isolated correctly I risk exposing the instrument to exceeding high differential and potentially damaging pressures of any one of the connections to atmosphere (1000KPa or 950KPa).

ISOLATION PROCEDURE for a YOKOGAWA EJX110A

Isolation of the Yokogawa EXJ110A DP Cell,

Step 1 – Secure all trips and let an operator know to put the controller in manual – we are about to take a process variable transmitter out of service.
Step 2 – Close the High and Low process line valves. The instrument is now isolated from the process impulse pressure lines
Step 3 – Open the equalising valve. Pressures are now equal on both sides of the measuring diaphragms resulting in nil differential pressure.
Step 4 – Open the bleed valves on the transmitter. No pressure remains in the instrument.

De-Isolation is not a reverse procedure, closing the equalising valve and opening the process line valves with even the slightest difference in time can cause unequal pressurisation of the measurement diaphragms. Instead we use this procedure.

Step 1 – Close the Bleed Valves
Step 2 – Confirm the equalisation valve is open.
Step 3 – Open the High process line valve. Equal High process line pressure is now present across the High and Low measuring diaphragms resulting in a nil differential pressure.
Step 4 – Close the Equalising Valve.
Step 5 – Open the Low process line valve. The instrument is now measuring differential pressure across the High and Low process impulse line connections. Instrument can be placed back in service.

360 VIEW YOKOGAWA EJX 110A

360 view of the Yokogawa EJX110a

WORKPLACE MENTOR – YOKOGAWA EJX 110A

Garry Hargreaves – Leading Hand Instrumentation
(Mob) 0417605546

Glen McMurtrie – Back To Back (BTB)
(Mob) 0417605546

WEB SITE – YOKOGAWA EJX110A

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SERVICE LOG – YOKOGAWA EJX110A

Location:
Separator Floor
Device: Flow Meter YOKO-EJX110A

Service Log

12_December_2015 – Commissioned – David Harrison
Yokogawa EJX110A commissioned without incident. All benchmark within specifications and calibrations settings. DH
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15_May_2016 – Calibration test – Michael James
Checked span and Zero points – routine testing process – All OK – MJ
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20_June_2017 – Calibration test – Garry Hargreaves
Checked span and Zero points – routine testing process – All OK – GH
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15_Dec_2018 - Maintenance check revealed water leaking from High Pressure impulse line. Reported and logged a service job. WEGH_1236