Horner APG QX751 OCS - Manual (Page 91)

MAN0890-02-EN CH. 16
August 20, 2009 Page 91 of 96 ECN # 979
16.3
CsCAN Network
For complete information on setting up a CsCAN network, refer to CAN Networks manual (MAN0799) by
visiting our website (
http://www.heapg.com ) for the address to obtain documentation and updates.
Network status, node ID, errors, and baud rate in the controller system menu are all in reference to the
CsCAN network. These indications can provide performance feedback on the CsCAN network and can
also be used to aid in troubleshooting. Refer to page 41 for full details on the system menu.
16.3.1 CsCAN Network Troubleshooting Checklist
1. Use the proper Belden wire type or equivalent for the network as specified in MAN0799.
2. The QX751 does not provide 24VDC to the network. An external voltage source must be used for
other devices such as SmartStix I/O.
3. Check voltage at both ends of the network to insure that voltage meets specifications of attached
devices.
4. Proper termination is required. Use 121-ohm (or 120-ohm) resistors at each end of the network. The
resistors should be placed across the CAN_HI and CAN_LO terminals.
5. Measure the resistance between CAN_HI and CAN_LO. If the network is properly wired and
terminated there should be around 60 ohms.
6. Check for duplicate node ID’s.
7. Keep proper wires together. One twisted pair is for V+ and V- and the other twisted pair is used for
CAN_HI and CAN_LO.
8. Make sure the baud rate is the same for all controllers on the network.
9. Assure shields are connected at one end of each segment -- they are not continuous through the
network.
10. Do not exceed the maximum length determined by the baud rate and cable type.
11. Total drop length for each drop should not exceed 6m (20 feet). A drop may include more than one
node. The drop length adds to the overall network length.
12. Network should be wired in "straight line" fashion, not in a "star" pattern.
13. In applications requiring multiple power supplies, make sure the V- of all supplies is connected
together and to earth ground at one place only.
14. In some electrically noisy environments it may be necessary to add repeaters to the network.
Repeaters can be used to add additional nodes and/or distance to the network and protect the signal
against noisy environments. The Horner APG repeater is part # HE200CGM100.