Micromod MOD: 30ML and Modcell Maintenance for 2001N, 2002N, and 1800R - Manual (Page 11)

MOD30ML and Modcell Maintenance
MODCELL STATUS INDICATORS
SECTION 2
MODCELL STATUS INDICATORS
2 .1 GENERAL
The red and green status LEDs on each MODCELL instrument, Figure 1 or 2, provide
continuous visual indication of the operational condition of the instrument. These LEDs have
five possible conditions as follows:
• Red off; Green off
• Red on; Green off
• Red off; Green on
• Red on; Green on
• Red flashing; Green on
Normal operation of the instrument in the RUN state is indicated by red off and green on.
The other conditions provide useful operational information when observed in conjunction
with events and conditions such as initial application of power, the instrument initialization
sequence, power-up after a shutdown, presence of a valid data base, use of a portable
memory module, and an I/O mismatch condition. The status LED indications are described in
detail in Section 2.2.
2 .2 INTERPRETING STATUS LED INDICATIONS
• Initial power-up
When power is applied to the instrument, the red LED turns on indicating presence of
power to the instrument. If the red LED remains on and the green LED fails to turn on, a
fault condition is present in the instrument. Examples of problems in this case include
identity module not present, select module failure, processor failure, memory failure, etc.
• After initialization sequence
After power up, the instrument and I/0 are initialized and the green LED is turned on.
From this point, several parameters affect the next state which the instrument can enter.
These include the presence of a backup memory module and if present, the setting of its
MODULE LOAD/NORMAL switch, the setting of the RUN/SERVICE switch on the front of
the instrument, the presence of a previous shutdown fault condition logged in the
instrument memory, the presence of a valid database in the instrument memory or in the
backup memory module, and if a database is present, parameters in the database such
as the warmstart / coldstart parameters, run on I/O mismatch, and physical I/0 population
vs. configured I/O module blocks.
• Power-up after shutdown
If the instrument is being powered up after it experienced a shutdown fault (checksum
error, spurious interrupt, watchdog, etc.), it will enter the DEFAULT state, leaving the red
and green LED's on. Previous shutdown fault information is recorded in the instrument
memory, and can be read with the read shutdown information message. The instrument
can not be removed from the DEFAULT state in this case until the shutdown is
acknowledged with the ACK shutdown fault message (see Section 6). When this
message is received, the instrument continues through the startup process and
advances to the appropriate state.
2 -1