Emerson ROC827 User Manual
Page 19
ROC827 Instruction Manual
Issued Mar-06
General Information
1-13
AGA 3 calculations conform to the methods described in American Gas
Association Report No. 3, Orifice Metering of Natural Gas and Other
Related Hydrocarbon Fluids. Based on the second and third editions, the
calculation method is 1992 AGA 3.
The AGA 7 calculations conform to methods described in American Gas
Association Report No. 7, Measurement of Gas by Turbine Meters, and
use the AGA 8 method for determining the compressibility factor.
The AGA 8 method calculates the compressibility factor based on the
physical chemistry of the component gasses at specified temperatures and
pressures.
The firmware supports liquid calculation methods ISO 5167 and API 12.
Factors for API 12 correction must be supplied through a Function
Sequence Table (FST) or user program. For more information, refer either
to the
1.4.4 Automatic Self Tests
The operating system firmware supports diagnostic tests on the ROC827
hardware, such as RAM integrity, Real-Time Clock operation, input
power voltage, board temperature, and watchdog timer.
The ROC827 periodically performs the following self-tests:
Voltage tests (battery low and battery high) ensure the ROC827 has
enough power to run while not allowing the battery to be overcharged.
The ROC827 operates with 12 Volts dc (nominal) power. The LEDs
become active when input power with the proper polarity and startup
voltage (9.00 to 11.25 Volts dc) is applied to the BAT+ / BAT–
connectors. Refer to Table 1-1.
The CPU controls the software “watchdog.” This watchdog checks the
software for validity every 2.7 seconds. If necessary, the processor
automatically resets.
The ROC827 monitors Multi-Variable Sensor(s), if applicable, for
accurate and continuous operation.
A memory validity self-test is performed to ensure the integrity of
memory.
1.4.5 Low Power Modes
The ROC827 uses low power operation under predetermined conditions
and supports two low power modes, Standby and Sleep.
Standby
The ROC827 uses this mode during periods of inactivity. When the
operating system cannot find a task to run, the ROC827 enters Standby
mode. This mode keeps all peripherals running and is transparent to