ITRON Centron, Technical Reference Manual

Page: 67 / 100

Operation: C12.19 C1SD, C1ST, and C1SL Versions
CENTRON® Meter Technical Reference Guide 57
The following events take place when an automatic demand reset occurs at a season change:
1 The current season energy registers are copied directly to the last season energy
registers.
2
The current season maximum demand registers are copied directly to the last season
maximum demand registers, and t rate is added to the cumulative demand register.
3 After the demand reset, the maximum demand registers are reset to zero, and the t rate
cumulative demand register is copied to the last season cumulative demand register.
If there is no demand reset at season change, all current season registers are directly copied
to last season registers at season change, but no current season registers are zeroed.
Load Profile Specifications
Capacity
The C1SL module provides 144 Kbytes of EEPROM for up to eight channels of interval
load profile data. The amount of installed EEPROM actually used for load profile recording
is programmable from 1 to 144 Kbytes in one Kbyte increments.
Bit Resolution
The mass memory is configured for 16 bit data resolution. Equivalent pulse count resolution
per interval is as follows:
Bits Pulse Counts
16 65,535
15
1
32,767
1
When a Net quantity (i.e., Net Wh) is chosen as a load profile channel, all load profile channels have
15-bit resolution.
There is a difference between MV-90 and the D/T/L Register concerning load profile
data. The D/T/L Register can accommodate a maximum of 65,535 pulses (16 bit) per
interval. (A maximum of 32,767 pulses per interval is allowed when using bidirectional
quantities because the 16th bit is used for "+" or "-"). MV-90 is a 16 bit system,
however the 16th bit is always used for "+" or "-". Since the 16th bit is always signed,
the maximum allowed pulses per interval is always 32,767. If MV-90 receives a number
of pulses per interval larger than 32,767, MV-90 will record a negative number
(received value) for that interval.
Itron recommends programming any D/T/L Register with load profile that is
interrogated by MV-90 or any system that exports load profile information to MV-90 to
use 15 bit resolution or 32,767 pulses per interval.