19
SAIA
®
S-Bus
This chapter describes how the individual registers, inputs, flags, etc. are approached.
No reference is made here to addresses of the respective inputs and outputs. Addresses are to be taken
from the type-specific device datasheet in question.
General
In order to enable using the SAIA
®
S-Bus, it is necessary to put the SASI initialisation “SASI S-Bus Master” before
the FBoxes used for communication.
Optional also the FBox “S-Bus Station” can be used for each individual fieldbus device. By means of this FBox
communication is optimised and after a fieldbus device failure, communication is recovered again.
Bus connection
The terminals A and B have different designations at the SAIA
®
S-Bus. These are to be allocated as follows:
A = ⁄ D
B = D
Analog values
Analog values are generally treated as WORD REGISTER (32 BIT) in the FB-II fieldbus system.
Temperature measurement data are forwarded as integer with 1 ⁄ 10 °C increments.
21,3 °C ............. corresponds to the value 213.
Active measurement and output values (0 .. 10 V and 0 ... 20 mA) are forwarded at a resolution of 1 ⁄ 100 of a unit.
6,7 V .................. corresponds to the value 670.
11,25 mA ......... corresponds to the value 1125.
Digital input
Digital inputs are treated as individual FLAGS (bits) in the FB-II fieldbus system.
Here it is immaterial whether only one or several inputs are read at the same time.
Digital output
Digital outputs are treated as individual OUTPUT (bits) in the FB-II fieldbus system.
Here it is immaterial whether only one or several outputs are written or read at the same time.
Emergency operation switches
Switches of the emergency operation level are treated as individual FLAGS (bits) in the FB-II fieldbus
system like digital inputs.
Here it is immaterial whether only one or several switches are read at the same time.
Emergency operation potentiometers
Potentiometers of the emergency operation level are treated like active analog inputs.
The potentiometer position corresponds to an output signal of the respective device type (0 .. 10 V)
and is forwarded at a resolution 1 ⁄ 100 of a unit.
U-type ...... 67% ........ corresponds to the value 670 or 6,7V respectively.
I-type ....... 50% ........ corresponds to the value 1000 or 10 mA respectively.
SASI S-Bus initialisation
In order to enable using the SAIA
®
S-Bus, it is necessary to place the SASI initialisation before the first communication
FBox in the FUPLA programme. This can be done by using the FBox “SASI S-Bus Master”.
Settings in the FBox:
Cannel ................................................... The PLC channel’s number used
TS-Delay ................................................ 0 ms
TN-Delay................................................ 0 ms
Timeout ................................................. 100 - 1000 ms (depending on complexity of network)
S-Bus Mode .......................................... Parity ⁄ Data
Gateway ................................................ No
RS Type ................................................. RS485
Transmission speed ............................ Select the same desired transmission speed, which is preset at the fieldbus devices.
S-Bus station (optional)
Optional also the FBox “S-Bus Station” can be used for each individual fieldbus device.
By means of this FBox communication is optimised and after a fieldbus device failure, communication is recovered again.
