Rockwell Automation 1756-CFM ControlLogix Configurable Flowmeter Module - Manual (Page 41)

41 Rockwell Automation Publication 1756-UM010B-EN-P - December 2011
Configurable Flowmeter Module Features and Operational Modes 41
Operating in Totalizer Mode
In Totalizer mode, the 1756-CFM module counts pulses and scales them to
engineering units. Every effort is made to store the least significant count even
when the least significant unit of the total is larger. The CFM module
calculates three forms of calculated frequency:
 Frequency over a fixed period
 Frequency over a requested number of samples
 Moving average of the frequency
All of the forms mentioned above are available in totalizer mode. In this mode,
the module also offers the following functions:
 Prover Function
 Filler Function
These functions are described later in this chapter.
Nonresettable Totalizer
Configure the CFM module for Nonresettable Totalizer mode to make sure
the total counts value is not reset during normal module operation. The CFM
module stores total count values up to 2
31
-1 (2,147,483,647) counts.
Terminal Usage in Totalizer Mode
In Totalizer mode, F0 and F1 are used as inputs. Z0 and Z1 are used as prover
signals.
Output Operation in Totalizer Mode
In Totalizer mode, outputs:
 can operate normally or be forced ON or OFF.
 can be tied to either flowmeter input. If one channel is configured for
trickle operation, both outputs are tied to that flowmeter input.
IMPORTANT
The total count value can be reset in Nonresettable
Totalizer mode if power is cycled to the module for any
reason (e.g. module is removed from and reinserted to the
chassis).