Endress+Hauser Proline Promag 55 Operating Manual page 121

Device functions Proline Promag 55 FOUNDATION Fieldbus
Endress+Hauser
6.2.4 Values for the parameters CAS_IN_D, RCAS_IN_D, OUT_D,
and SP_D
Via the Discrete Output function block, different instrument functions in the Transducer Block can
be initiated via manufacturer-specific, fixed set point values from an upstream function block.
Here it must be observed that the desired function is only then executed when a status change from
the value 0 (Discrete state 0) to the corresponding function value (following table) takes place. The
value 0 always serves as the starting point for the corresponding control of instrument functions. A
status change from a value not equal to zero to another value has no effect.
Input allocation of the parameter CAS_IN_D, RCAS_IN_D, OUT_D, SP_D
Status changes
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
→
Discrete state 0
Example for the control of positive zero return via the Discrete Output function block.
The following example is intended to illustrate how positive zero return can be activated and
deactivated during a rinsing process by an upstream function block via the Discrete Output function
block.
1. In the first step, the connection between the Discrete Output function block and the
Transducer Block must be established. Here, the value 16 must be assigned to the
parameter CHANNEL in the Discrete Output function block.
→ Parameter CHANNEL → 16 (= Discrete Output function block)
2. In the CAS operating mode, the Discrete Output function block processes the set point value
prescribed at the input CAS_IN_D by the upstream function block and transfers it to the
Transducer Block.
Activating positive zero return
With a starting value of 0 (Discrete state 0), the positive zero return is activated by a status
change from 0 to 2 at input CAS_IN_D.
Deactivating positive zero return
Positive zero return can only then be deactivated when the input value at CAS_IN_D has first
been set to output value 0 (Discrete state 0). Only then can positive zero return be deactivated
through a status change from 0 to 2 at input CAS_IN_D.
Action
Discrete state 1 Reserved
Discrete state 2 Positive Zero Return ON
Discrete state 3 Positive Zero Return OFF
Discrete state 4 Reserved
Discrete state 5 Reserved
Discrete state 6 Reserved
Discrete state 7 Reset Totalizers 1, 2, 3
Discrete state 8 Reset Totalizer 1
Discrete state 9 Reset Totalizer 2
Discrete state 10 Reset Totalizer 3
6 Discrete Output Function block
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