Operating Modes; Weighing Steps; Nawi - Non Automatic Weighing Instrument; Nawi - Non-Automatic Weighing Instrument - Filling - Siemens SIMATIC ET 200SP Operating Instructions Manual

6.4

Operating modes

6.4.1

Weighing steps

Dosing is always executed in weighing steps. These weighing steps involve the same task in
each weighing operating mode and are presented below. The scale status in the interface DB
of the "cyclicIoData" structure indicates the current weighing step of the scale.
Weighing step
0
1
2
3
4
5
6
6.4.2

NAWI - Non automatic weighing instrument

6.4.2.1

NAWI - Non-automatic weighing instrument - Filling

In this weighing operating mode, intervention by the operator is always required in the case of
a legal-for-trade verified scale. The operator initiates logging of the current weight with a
command. The operator can initiate the command from the SIMATIC HMI, for example. The
material to be weighed is dosed into or placed on the scale.
The material to be weighed is placed on a platform weighing machine, for example, and an
entry is made in the log memory of the electronic weighing system by a user command.
In NAWI mode, the electronic weighing system also allows a set point to be set. The set point
is automatically dosed by means of the dosing functionality of the electronic weighing system.
The user logs the dosed weight with a command. Manual logging is not included in the
automatic weighing cycle.
The dosing signals "Coarse flow/Fine flow" can be used to directly control the corresponding
dosing elements. After the set point is reached, the electronic weighing system jumps to
"stopped" state in weighing step 4. The operator confirms the dosed weight using the "Continue
weighing" (1141) command. The operator logs and ends the weighing operation and continues
to weighing step 5 for emptying.
In practice, the dosing process may proceed as follows:
1. PLC sends set point (DR20) and material parameter (DR23) to the electronic weighing
system
2. PLC sends "Start" command (e.g. 1101) to the electronic weighing system
3. The electronic weighing system performs zeroing or tares (based on DR25)
Technology module TM SIWAREX WP351 HF
Operating Instructions, 01/2020, A5E47521010-AA
Function
Scale waits for command
Taring/zeroing (based on dosing start settings from DR25)
Extra coarse/Coarse/Fine phase (based on settings from DR23)
Post-dosing (based on settings from DR22)
Checking (based on settings from DR22)
Emptying (based on settings from DR25)
Checking of actually emptied material Only for DTI Discontinuous totalizing auto‐
matic weighing instrument (Page 57) Modus B
Parameter assignment/addressing
6.4 Operating modes
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