User Manual

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Building Technologies M-bus System CE1P5361en
HVAC Products 7 Technical data 08.02.2007
7 Technical data
7.1 M-bus
7.1.1 Specification
M- bus system
Designation Condition Minimum Typically Maximum Unit
WZC-P250 / -R250 0 250 Number of slaves per
segment
n
WZC-P60 0 60
Rate of data transmission T @ C
Segment
 382 nF 300 2,400 9,600 Baud
Bus voltage (system) U @ I
M
= 0…400 mA 12 42 V
Bus voltage (master, idle
condition ‘1‘)
U
M,
R
@ I
M
= 0…400 mA 24 40 42 V
Bus voltage (master,
send ‘0‘)
U
M,s
@ I
M
= 0…400 mA U
MR
–12 U
M,R
–8.2 V
Bus voltage (slave idle
condition ‘1‘)
U
S,R
@ I
S
 1.5 mA  21  42 V
Bus voltage (slave recep-
tion ‘0‘)
U
S,E
@ I
S
 1.5 mA  12 V
WZC-P250 / -R250 0 375 mA
Bus idle current (master)
I
M,V
WZC-P60 0 90 mA
Bus short-circuit current
(master)
I
M,K
WZC-P250 / -R250 470 500 530 mA
WZC-P60 130 155 160 mA
Idle current (slave) I
S,R
@ U
S
= 21…42 V 0.75 1.2 1.5 mA
Transmit current (slave) I
S,S
@ U
S
= 12…42 V 11 20 mA
7.2 RS-485 specification
Specification
Designation Condition Minimum Typically Maximum Unit
With WZC-P250 2 2 2
Number of RS-485 users
(including the central unit)
m
With WZC-P60 2 2 2
Rate of data transmission
T 300 2,400 9,600 Baud
Cable length
l 1,200 m
Bus voltage (Transmit)
U
T
 1.5  2.5  5 V
Bus voltage (Receive)
U
R
 0.2 V
7.3 Copper cable, loop resistance
Diameter [mm] Cross-sectional area [mm
2
] Loop resistance [  /km]
0.4 0.13 283
0.6 0.28 126
0.8 0.50 71
1.13 1.0 36
1.38 1.5 24
1.60 2.0 18
1.78 2.5 14