Siemens Maxum II Manual page 68

General Maintenance and Troubleshooting
4.6 Alarm Codes, Descriptions, and Suggested Actions
# ! Text
2901, ? Deviation [1 - 2] Exceeded
2902 on %4
2903, ? Ramp has no origin [1 - 2]
2904 on %4
68
Description
Temperature controller PIC: The meas‐
ured temperature deviation (TEMP_DE‐
VIATION) has exceeded the correspond‐
ing MAX_DEVIATION value. The PID
control was not successful to control the
heater with the desired precision on
channel #1. A large deviation is normal
on power-up and immediately following
a change in the temperature setpoint.
Temperature controller PIC: A ramp rate
was set without a prior temperature set‐
point on channel #1. A ramp must have
an initial temperature defined by the pre‐
vious setpoint value.
Action
Check for:
Improper controller type 'temptype' se‐
lected in the 'App_tempctl' table.
The PID parameters are not optimal.
Fast variation in the ambient tempera‐
ture, airflow or line voltage.Insufficient
air flow. For an air bath heater with 1/8
inch spargers, 3 cfm is adequate for up
to 100 DegC and then 4 cfm should be
used.
A temperature setpoint too high for the
allowed T-rating.
An Air pressure switch that works inter‐
mittently.
A defective DPM.
A defective PECM.
A defective Solid State relay.
Set the power-up default ramp value to
0.
Maxum edition II Analyzer General Maintenance
Manual, August 2018, A5E42019842001