Hardware manual

Chapter 2 - TeleFlow Standard ACCOL Load
TeleFlow™ 2-3 Standard ACCOL Load
obtained by summing the Extensions computed every second during the interval
and dividing by the number of Extension values summed. The Extension sum is
then cleared and averages are reset for another Calculation interval.
There are several conditions, which force the Calculation interval to be 1 second as
follows.
1. When the Local communications port is in use.
2. When the LCD Display is active (i.e scrolling data for the operator).
3. When PID flow control is active and the flow rate is not within 2% of the
setpoint.
4. When the Network Port is active (Carrier Detect is high)
In addition to the input signal averages for the Calculation interval, another set of
input averages is maintained for each full log period (hour or 15 min) and day;
these averages are stored in the Archive for that log.
Process Inputs: Differential Pressure (DP), Static Pressure (P),
Temperature (T)
The process inputs used for the Gas Flow computations are Differential Pressure
(DP), Static Pressure (P), and Temperature (T). The DP and P come from the
internal, multivariable sensor; the Temperature is measured by an RTD probe.
Each second, these values are acquired from the internal sensor and placed in the
'live data' signals.
Input Averaging
The process inputs DP, P and T 'live data' values are averaged over the configured
Calculation interval; the average is a 'flow-dependent time-weighted' value in
accordance with MPMS requirements. The averages are calculated for the periods
of time when the DP is above the user configured Cutoff level. When there is no
flow for the entire Calculation interval, straight arithmetic averages are calculated
for the Static Pressure and Temperature. At the end of each Calculation interval
the calculated averages are stored in the 'in-use' signals and used to calculate flow
rate and volume.
Separate averages of DP, P, and T are maintained for each log period (hour or 15
min) and the day.