SAMES KREMLIN
Page 27
Manual : 573.176.112
CALCULATION AND DISPLAY OF THE DISPENSED WEIGHT
The extruded weight is displayed on the screen.
In manual mode, all the successive extrusions are cumulated. No reset to zero is made between each
extrusion.
In automatic mode, the display is refreshed all the 300 ms and is fixed at the end of extrusion. The
display is maintained until the beginning of the next extrusion.
The end of extrusion is defined as when the extrusion inlet has changed from active to inactive.
The passage from a mode to another (manu<>auto) leads to the reset to zero of the display.
The extruded weight is obtained by means of the following formula (within about a sign) :
(Position at the beginning (mm) - Current Position (mm)) * Section (mm2)* Density.
This result is divided by 10000 to obtain the weight in gram. All calculations are made in whole value,
without fluctuating calculation. The result is rounded to the gram.
During the piston moving stage, the value displayed is the value that is applicated.
15- COMMUNICATION
PROTOCOL
The protocol of communication used is a light version of ModBus.
At the beginning, the protocol was for operating in a MODICON (Schneider) programmable automaton
environment. As some of the functions are appropriate to an automaton, only the functions of reading /
writing of words (individual or by blocs) and a function of test are kept. They are :
Functions 3 and 4
: multiple reading of words (virtual address in word).
Function 5
: writing of a byte in Boolean (in RAM only)
Function 6
: writing of a word (in RAM)
Function 8
: under function 0, simple echo of line (test of communication)
Function 16
: writing of N words
All functions not implemented are treated as illegal functions (sending n°1 specific ('ILLEGAL
FUNCTION'))
Protocol available on the web site www.modicon.com
Document of reference :
Modicon ModBus Protocol (in English only)
PI-MBUS-300 Rev. J
DATA EXCHANGE
The partition of zones available by the protocol corresponds to the physical mapping of the
MC9S12DP256 central processing unit.
The ModBus addresses are always under the form of words, but the microcontroler addresses are
always under the form of bytes. Then, there is still a 2 factor between the ModBus addresses and the HC
12 addresses. Theoretically, only the ModBus addresses interest the user.
Physical Inlets/ Outlets
The inlet-outlet zone from 0 to 3FF corresponds to the microcontroler inlets/outlets.
For operating safety reasons, it is only available in reading.
For the understanding of the datas, please refer to the Motorola document.
The zone covers the 0-3FF space that is to say from 0 to 1FF in ModBus.
That access, without interest a priori, can enable a possible dagnosis of the card by distant connection.