SST confirms unique diagnostic capabilities

Waterloo, Ontario, Canada— In a recent comparison of DeviceNet diagnostic tools, SST found that its NetAlert NetMeter for DeviceNet has several essential capabilities not demonstrated by any other DeviceNet diagnostic product. This contradicts an earlier claim by Synergetic that its product matched all of NetMeter's functions.

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Waterloo, Ontario, Canada— In a recent comparison of DeviceNet diagnostic tools, SST found that its NetAlert NetMeter for DeviceNet has several essential capabilities not demonstrated by any other DeviceNet diagnostic product. This contradicts an earlier claim by Synergetic that its product matched all of NetMeter's functions. [See "Synergetic reports first DeviceNet diagnostic tool," News, CE , Jan.'01, p.22; responding to "New tools improve network diagnostics, maintenance," Technology Update, CE , Nov.'00, p.14]

Nick Jones, principal researcher at SST and chief technical officer of ODVA, reports that the NetMeter independently measures dominant and recessive voltages of a network's CANH and CANL wires and determines the system common mode voltage, all of which are key indicators of network health, while Detective merely measures the average dc voltage of the CANH and CANL wires. SST also reports that both products measure the bus power voltage, but with the NetMeter providing significantly better accuracy. SST adds that NetMeter is a passive device that cannot affect the network being tested, which makes it safer for non-experts to use, while Detective is an active device, which means there's a significant chance that an unskilled operator without proper training will adversely affect a network under test. In addition, NetMeter has an internal battery that allows measurements to be frozen and viewed later, while Detective's problem list is cleared each time it's disconnected or the network's power is shut off.

SST points out that the NetAlert product family includes in-the-wire 24/7 early warning diagnostics in addition to the NetMeter physical layer validation tool, while the Detective is a hand-held configurator with some diagnostic capability, but is not part of a cost-effective network maintenance suite with 24/7 early warning features.

For more information, including SST's complete report on DeviceNet diagnostic tools, visit "News," CE, April '01, online at www.controleng.com.