KRAL BEM 100 - Specifying the Maximum Flow Rate; Specifying the Minimum Flow Rate; Reading the Measured Values and Status Information; Synchronizing Measured Values

9 Operation
9.2 Reading the measured values and status information
9.1.8 Specifying the maximum flow rate
The maximum flow rate in [l/h] is specified by using the parameter "Maximum_Flow_Rate". If the cur-
rent flow rate exceeds the value specified in the parameter, an error message is output, see
"Alarm 29".
Enter the desired value times 100 in the parameter "Maximum_Flow_Rate".
Example: The entry 35500 corresponds to 355.00 l/h.
9.1.9 Specifying the minimum flow rate
The minimum flow rate in[l/h] is specified by using the parameter "Flow_Zero_Threshold".
This ensures that the flow rate changes to zero after a defined period(1/f
ug
), irrespective of its aver-
aging. If the flow lies below this limit, the average flow rate is set to zero. However, the volume or mass
respectively continues to be taken into consideration for the calculation of the total values.
If zero is entered as the limit, the average flow rate only changes to zero after a certain delay. The dur-
ation of this delay corresponds to the reaction time of the averaging.
Enter the desired value times100 in the parameter "Flow_Zero_Threshold".
Example: The entry5 corresponds to 0.05l/h.
9.2 Reading the measured values and status information
9.2.1 Synchronizing measured values
Synchronization between the measurements in the feed and return lines is advisable for the differential
measurement. A waiting mode is available to this purpose. This is controlled via the parameter
"Hold_Timer". At an activated waiting mode the current measured values, meaning the automatically
updated parameters, are frozen for a specified waiting period.
Activating the waiting mode for one processing unit
Enter the waiting period in [ms] in the parameter "Hold_Timer".
ð The counter immediately begins to count down. The remaining period of the waiting mode is
entered in the parameter "Hold_Timer". The measured values continue to be updated internally dur-
ing the waiting period.
Activating the waiting mode for several processing units
Enter the Modbus address 0 and the waiting period in [ms] in the parameter "Hold_Timer".
ð The parameters "Alarm_Read", "Total_Volume_2", "Avg_Flow_Rate", "Temperature" and
"Flow_Dir_Change" are read.
Deactivating the waiting mode
Enter the waiting period 0 in the parameter "Hold_Timer".
Increasing the waiting period
Before the counter has reached the value zero, enter a new waiting period in [ms] in the para-
meter "Hold_Timer".
Example:
One set of measured values is to be read per second in a flow rate measuring system with one flow-
meter each in the feeder and return line.
1. Enter a waiting period of 500ms and the Modbus address0 in the parameter "Hold_Timer" so
that both processing units can be set simultaneously into the waiting mode.
The waiting period can be selected freely. A waiting period of500ms is sufficient so that the cur-
rent measured values of the two flowmeters can be read and have expired before the next read-
ing.
2. Read the measured values from Processing unit 1.
ð Read the parameters "Alarm_Read", "Total_Volume_2", "Avg_Flow_Rate", "Temperature" and
"Flow_Dir_Change" of Processing unit 1.
3. Read the measured values from Processing unit 2.
ð Read the parameters "Alarm_Read", "Total_Volume_2", "Avg_Flow_Rate", "Temperature" and
"Flow_Dir_Change" of Processing unit 2.
4. Calculate the quantity and difference of the flow rates.
ð The waiting mode ends automatically after500ms.
Operating instructions
OIE 26en-GB Edition 2021-08
19