I-7590 Quick Start v1.00, July 29, 2014 -------------------------------------
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3. Wire Connection
M-Bus:
A two-wire standard telephone cable (JYStY N*2*0.8 mm) is used as the
transmission medium for the M-Bus. The maximum distance between a slave
and the repeater is 350m; this length corresponds to a cable resistance of up
29Ω. This distance applies for the standard configuration having Baud rates
between 300 and 9600 Baud, and a maximum of 250 slaves (I-7590 supports
max 100 slaves). The maximum distance can be increased by limiting the
Baud rate and using fewer slaves. In the standard configuration the total cable
length should not exceed 1000m, in order to meet the requirement of a
maximum cable capacitance of 180nF.
The number of terminals that can be connected to a repeater and the
structure of the segments within an extended M-Bus system are determined by
the type of cable and the Baud rate.
