Troubleshooting
CsCAN Network
For complete information on setting up a CsCAN network, refer to CAN Networks manual (MAN0799) by using
Horner's Documentation Search page.
Network status, node ID, errors, and baud rate in the controller System Menu are all in reference to the CsCAN net-
work. These indications can provide performance feedback on the CsCAN network and can also be used to aid in
troubleshooting.
CsCAN Network Troubleshooting Checklist
1. Use the proper Belden wire type or equivalent for the network as specified in the CAN Networks Manual,
MAN0799.
2. The Horner OCS 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 ensure that voltage meets specifications of attached devices.
4. Proper termination is required. Use 121Ω (or 120Ω) 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 60Ω.
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’). 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 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 envir-
onments.
USB Interfaces
n
Plugging and unplugging USB devices while the OCS is powered up can cause the OCS to reset. In general,
branded USB memory sticks will not cause this problem, however, with the advent of USB 3.0 and larger /
faster memory devices this cannot be guaranteed.
n
Larger USB devices such as hard-drives etc. should only be attached and removed when the OCS is
powered down.
n
The resets are caused by short sharp current spikes when devices are added or removed from the OCS,
these spikes can exceed the USB specification but are usually very short and mostly do not cause problems.
Some devices however draw a longer larger current as they power up causing a brief dip in the OCS internal
supplies leading to a reset.
n
Standard SanDisk and Kingston ranges with read times less than 120MB/sec. should not cause resets. The
display will flicker when a device is added or removed.
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