Replacing An Epc Module - Siemens Maxum II Reference Manual

The EPC receives commands from the SYSCON via I
setpoint. The timing of messages from the SYSCON controls timing within the EPC. There is
no time base in the EPC. Module control is established by sending parameters, such as
setpoint pressures and ramp rates to the EPC. The EPC is used in the Maxum II to control the
carriers and/or fuels for the detector modules. The EPC can also be used in field-mounted
installations.
The EPC communicates with other components via the I
pressure back to the SYSCON. Regulated pressure range is 5-100psig.
Channels
Each EPC channel consists of a pressure sensor amplifier and analog filter followed by an A/
D Converter. The converter is read by the local controller that calculates a new control value
used to control the proportional solenoid valve.
Control parameters, such as set-point pressures are sent via the I
and diagnostic data is available via software.
Diagnostics
EPC diagnostics are read-back of setpoint pressure via the software, DC power within
operating limits, monitoring of line and short-term pressure variations with respect to the
setpoint regulation, out of range pressure alarm and a diagnostic failure.
2.9.2

Replacing an EPC Module

Voltage dangerous to life exists. Failure to follow proper procedures may result in equipment
damage, personal injury or death.
Before performing the removal and installation procedures, it is important that primary AC
power to the Maxum II be turned off from the main circuit breaker. Observe all plant safety
requirements before performing any repair or maintenance on the Maxum II.
Note
Do not over-tighten ferrules. Oertightening may damage the ferrules.
The ferrules connected on the gas supply side of the EPC manifold are composed of vespel-
graphite. To prevent damage, these ferrules must NOT be over-tightened. Proper tightness
is typically ½ turn past finger-tight.
Note
Do not disassemble the EPC.
The EPC is made up of a manifold that is mounted to the electronic enclosure wall on standoffs
and the module itself. Due to safety and certification issues, it is necessary to replace both the
EPC and manifold as one assembly.
Maxum II Reference Manual
Manual, 7/2017, 2000596-001
Electronic Compartment Component Descriptions and Maintenance Procedures
WARNING
2.9 Electronic Pressure Control Module
C bus regarding timing and pressure
2
C bus and communicates actual
2
C bus to the EPC. Status
2
83