Emerson Process Management 53eA Benutzerhandbuch

Display segments missing 

Replace display board

Alarm relays are chattering

1. Check alarm setpoints.
2. Increase hysteresis time delay settings (see Section 5.7)

Incorrect current output

1. Verify that output load is less than 600 

Ω.

2. For minor errors, trim outputs (see Section 13.0)
3. Replace power supply board

Display too light or too dark

Change contrast (see Section 5.5)

“Level 1, 2 or 3 security: Lock” shown in display

Controller has password protection (see Section 5.13)

“Hold mode activated” showing in display

Controller is in hold (see Section 5.6, steps 10 and 11)

“Simulating output 1 or 2” showing in display

Controller is simulating outputs (see Section 5.4)

“Simulating alarm 1, 2, 3 or 4” showing in display

Controller is simulating alarms (see Section 5.4)

To check the performance of the controller, use a decade box to simulate the current from the oxygen sensor.

A.  Disconnect the anode and cathode leads from terminals 1 and 2 on TB3 and connect a decade box as shown

in Figure 15-1. It is not necessary to disconnect the RTD leads.

B.  Set the decade box to the resistance shown in the table.

C.  Note the sensor current. To view the sensor current from the

main display, press any key to enter the main menu. Move the
cursor to "Diagnostics" and press Enter (F4). The sensor cur-
rent is the second line in the display. Note the units: 

μA is

microamps, nA is nanoamps.

D.  Change the decade box resistance and verify that the correct

current is shown. Calculate current from the equation: 

current (

μA) = 

499ADO

-675 mV

34 k

Ω

20 

μA

499A TrDO

-800 mV

20 k

Ω

40 

μA

Hx438 and Gx448

-675 mV

8.4 M

Ω

80 nA

voltage (mV)

resistance (k

Ω)