JVL MAC050 User Manual page 117

4.4 Expansion Modules MAC00-FC2/FC4
The function code classifies the communications objects, and controls the transmission
priorities. Objects with a small function code are transmitted with high priority. For ex-
ample, in the case of a simultaneous bus access an object with the function code "1" is
sent before an object with the function code "3".
Node address:
Every device is configured before network operation with a unique 7-bit long node ad-
dress between 1 and 127. The device address "0" is reserved for broadcast transmis-
sions, in which message, are sent simultaneously to all devices.
PDO, SDO, EMCY, NMT and heartbeat are using the header frame for communication
on the CANopen® bus.
4.4.7 Connecting MAC00-FC2/FC4 to the CAN bus
Before you connect the MAC00-FC2/FC4 to the CAN bus shall the Baud-rate, the
Node-ID and the termination must be selected.
On the serial bus it is possible to have a transmission speed (Baud-rate) of max. 1000
Kbit/s and a min. of 10 Kbit/s. The Baud-rate depends on the cable length, and the wires
cross-section, the table below have some recommendations for networks with less than
64 nodes. Recommended bus cable cross-section are according to CiA®:
Bus Distance
(m)
The bus wires may be routed in parallel, twisted and/or shielded, depending on EMC re-
quirements. The layout of the wiring should be as close as possible to a single line struc-
ture, in order to minimize reflections. The cable stubs for connection of the bus node
shall be as short as possible, especially at high bit rates. The cable shielding in the house
shall have a large contact area. For a drop cable a wire cross-section of 0.25 to 0.34 mm²
would be an appropriate choice in many cases. In section 4.3.46 of this chapter there is
an overview showing various JVL standard cables. All the JVL cables are twisted and
shielded.
For bus lenghts greater than 1 km, a bridge or repeater device is recommended. galvanic
isolation between the bus nodes is optional. The MAC00-FC2 and FC4 modules the gal-
vanic isolation is integrated to obtain best possible immunity against noise and differences
in the voltage potential between the nodes.
JVL Industri Elektronik A/S - User Manual - Integrated Servo Motors MAC050 - 800
Cross-sec-
2
tion (mm
25 0.25-0.34
100 0.34-0.6
250 0.34-0.6
500 0.5-0.6
500 0.5-0.6
1000 0.75-0.8
Terminator
) (ohm)
120
150-300
150-300
150-300
150-300
150-300
Baud-rate
(Kbit/s)
1000
500
250
125
100
50
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