SICK Barcode Scanner and DeviceNet

[Mushu 0]

Hi all, I have a Sick barcode scanner connected with a CDM490 and a CMF400-DNS board for DeviceNet. I need to connect it to a 1747-SDN SLC DeviceNet scanner, but when I open RSNetworkx the barcode scanner is not detected in the network. If I disconnect the barcode scanner the network is healthy and everything is working, but when I connect the barcode scanner the network fails. Error 91 appears in the Devicenet scanner. As far I understand when you connect a new item, even if it is not in the network configuration, the network would keep working. But it doesn't. Has anybody came across this before? Thanks, Mushu

[Ken Moore 23]

I would double check the cables, grounding etc...

[Mushu 0]

Hi Ken, I have checked the cables, I have resistors at the ends,... everything looks ok, but it doesn't work. Thanks, Mushu

[BobLfoot 301]

Error 91 indicates a "Buss Off" condition exists in your network. Some things to check and additional information you can provide. 1. How many devices on your network before you add the Sick Scanner Unit? 2. What is your network baud rate and is the Sick Unit set to match it. 3. Is the Sick Unit set to default to node 63 or is it set to occupy an unused node number? Here are some possibilities of what is happening. If you have a small 2 node network and add the Sick as a third node, but it happens to have a duplicte address to one the existing nodes then both duplicate devices will shut down and with the scanner seeing only itself it will go "Buss off". If the Sick Unit is set for some baud other then the rest of the network it is possible it's attempts to communicate will be seen as noise and the Scanenr will go "Buss Off". Check the voltage from P24 to Ground at each node on the network. It is a little known fact that the difference between the P24 mxaimum node and the P24 minimum node cannot exceed 5 volts. This means if the max node reads 26 volts no node can read below 21 volts. Other wise issues will result which might cause a "Buss off"

[Ken Roach 194]

The Error 91 indication on the 1747-SDN is definitely a Bus-Off condition. A mismatch in data rate (125 kb/s versus 500 kb/s, for example) is a common cause of a Bus-Off condition. Examine the pinout of the CMF400 device carefully and be sure there are no short circuits or misterminations. Turn off the DeviceNet supply voltage and measure the resistance between the blue and white wires; you should measure about 60 ohms.

[Mushu 0]

Thank you everybody for your help. Finally I got an answer from Sick. My barcode scanner firmware doesn't support DeviceNet. The reason why it took so long to find it out is because I don't know yet how to know the firmware version yet. Apparently it is written on the box of the devices, but obviously we don't keep the boxes. So I have to give the manufacture date of the scanner, and then sick checked if it was compatible or not. In the next few weeks I will get a newer version, so I will let you know how I'm getting on. Thanks again, Mushu