Contemporary Control Systems BASremote User Manual (firmware 3.1.x) - Manual (Page 32)

TD040300-0MF
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6.1.3.5 Modbus Configuration
Modbus configuration (see Figure 19) is only required if Modbus serial devices are
attached to the MB bus. Communication settings between the Master module and the
Expansion modules are preset and cannot be changed.
Modbus Address Address 1 is pre-assigned to the Master module while
Expansion modules are assigned addresses 2, 3 and 4
assuming Expansion units exist. The actual Expansion
address depends upon the order of cabling to the Master.
In addition to address 1, the Master module is also pre-
assigned addresses 8 and 9 for internal functions. It is
best to assume that addresses 1 through 9 are reserved
for BAS Remote equipment so assign addresses from 10
to 247 to attached Modbus devices.
Baudrate All Modbus devices attached to the MB bus must have the
same baud rate. Baud rates range from 2,400 to 115,200.
The default is 19,200.
Protocol All Modbus devices attached to the MB bus must use the
same protocol. The choices are RTU and ASCII. The
default is RTU.
Parity All Modus devices attached to the MB bus must use the
same parity. The choices are NONE, ODD or EVEN. The
default is EVEN.
Command Timeout Set how long the Master will wait for a slave to respond.
The range is 50
–3000 ms with a default of 1,000. If a
device fails to respond, it is placed into an offline queue.
Devices in this queue are checked every offline poll period.
Inter Scan Delay Set the desired delay between each poll cycle from 100-
30,000 ms. The default is 2,000.
Offline Poll Period Set how often the Master will check to see if a slave device
is back online. The range is 2,000-30,000 ms. The default
is 15,000.
Consecutive Read Delay Sets the delay between back-to-back accesses of the
same slave device. The range is 0-100 ms and the default
is 0.
Inter-Character Gap This maximum (1.5 character times) is what Modbus allows
between characters. If a device exceeds the allowable
time, set this to the highest possible value for the device.
The default of 0 is recommended, but settings between 0
and 10 ms are possible.