SCT-20 Series
32
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3.7 PROFIBUS
• The SCT20-PB works as a PROFIBUS DP V0 source in a PROFIBUS-DP network.
• Load the included .gsd file (Profibus_20.gsd) attached to the instrument in the development system of the PROFIBUS
primary.
• The available modules are:
•
R
= the register can be read only
•
W
= the register can be written only
•
R/W
= the register can be both read and written
GROSS WEIGHT – NET WEIGHT – PEAK
The weight values are expressed as positive integer numbers, include decimal figures but without decimal point.
Read the Status Register to obtain information about sign and possible errors on the weight.
To find out the decimal figures use the division module value;
Example: the net weight is 100000 and the division is 0.001 (three
decimals), the real weight value is 100.000kg.
Setpoints – Hysteresis
The weight values are expressed as positive integer numbers, include decimal figures but without decimal point.
• To set the value to 0; write the hexadecimal value hex 80000000 to the register (the most significant bit is 1 and all the
other bits are 0).
• To set them correctly consider the module Division value; E.g. to set a set-point to 100kg and the verification division
value is 0.001, set the set-point value to 100000 (remove the decimal points from the value that would be 100.000 with
decimals).
• If from PLC, a values is set out of the permitted interval (from 0 (not included) to full scale) the value is ignored and the
bit 13 (Writing error) rises in the Status Register.
Setpoints and Hysteresis are stored to the RAM volatile memory and lost upon instrument power off. To save them
permanently in the EEPROM memory, so that they are maintained upon the instrument power on, it is necessary to
send the command 99 (Save data in EEPROM) of the Command Register.
MODULE
Saving to EEPROM
N. Byte R N. Byte W ACCESS
GROSS WEIGHT)
4
R
NET WEIGHT
4
R
PEAK WEIGHT
4
R
SETPOINT 1
Only after command
99
of the
COMMAND REGISTER
4
4
R/W
SETPOINT 2
4
4
R/W
SETPOINT 3
4
4
R/W
HYSTERESIS 1
4
4
R/W
HYSTERESIS 2
4
4
R/W
HYSTERESIS 3
4
4
R/W
Divisions and Units of measure
2
R
Visualization Coefficient
4
R
INPUTS
2
R
OUTPUTS
NO
2
2
R/W
STATUS REGISTER
2
R
COMMAND REGISTER
NO
2
W
Sample Weight for calibration
Use with command
101
of the
COMMAND REGISTER
4
4
R/W
Table 3-10. PROFIBUS Modules
Note