ProSoft Technology MVI56-AFC - Manual (Page 294)

Reference MVI56-AFC ♦ ControlLogix Platform
User Manual Liquid and Gas Flow Computer
Page 294 of 316 ProSoft Technology, Inc.
February 25, 2011
Address Type Description
Ch00006 Bm Site status
bit 0 - AFC released
Latched when both bit 15 (cold start) and bit 12 (Processor offline) first become clear,
remaining so until any subsequent cold start. While this bit remains clear events are
not logged, allowing an initial configuration to be fully completed without filling up the
event log.
bit 1 - Checksum alarm
Set when any bit in the "Checksum Alarms" registers, for site and each meter, is set;
clear when all such bits are clear.
bit 2 - [reserved]
bit 3 - [reserved]
bit 4 - Processor halted, offline, or missing
Set while backplane communication is faulty, which typically occurs when the
Processor is switched to program mode. While set, measurement continues using the
latest process input values obtained from the processor. Upon resumption of
backplane communication, the AFC compensates for the downtime by computing an
accumulator increment in a manner that depends on the meter type. For differential
(orifice) meters, the first measurement scan acquires a scan period equal to the period
of downtime as computed from the system timer, hence periods of processor downtime
shorter than the rollover period of the system timer cause no loss of product. For linear
(pulse) meters, the first measurement scan acquires a pulse increment equal to the
difference between the processor-supplied pulse count of the current scan and that of
the last scan before communication loss, hence periods of processor downtime shorter
than the rollover period of the counter module cause no loss of product.
bit 5 - Measurement configuration changed
Set when any bit in the "Measurement Configuration Changed" registers is set; clear
when all such bits are clear.
bit 6 - Power up
Set upon power-up, and cleared upon setting the wallclock for the first time..
bit 7 - Cold start
Upon power-up, AFC’s non-volatile storage is checked for validity, by verifying a
checksum and confirming that certain known values are present in their proper
locations. If the storage is invalid, then it is initialized with a default configuration, and
this bit is set. The bit remains set, even through subsequent power cycles, until at least
one meter is enabled at which time the bit is cleared.
bit 8 - A copy of the "Hard Passwords" site option, made available here so that an
external application such as AFC Manager can learn all it needs to know in order to
connect to the module by reading the first 20 holding registers from the Modbus table.
bit 9 - [reserved]
bit 10 - [reserved]
bit 11 - [reserved]
bit 12 - [reserved]
bit 13 - [reserved]
bit 14 - [reserved]
bit 15 - [reserved]
Ch00007 By Processor offline code: 0 online, 1 offline
Ch00008 By Zero / primary slave address
This value distinguishes the two slaves. When read from the primary slave this value is
zero; when read from the virtual slave this value is the primary slave address.
Ch00009 Wd Password, write-enable