NetAlert NetMeter User Manual

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NetMeter for

DeviceNet

Patent Pending

7IAH\I /KE@A

P/N 715-0016 V1.2

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Summary of Contents for NetAlert NetMeter

Page 1 NetMeter for DeviceNet Patent Pending 7IAH\I /KE@A P/N 715-0016 V1.2...
Page 2 Essentials Read this first! NetMeter requires 2 ‘AA’ Alkaline batteries for viewing measurements offline. NetMeter must be plugged into a powered network to get most measurements. NetMeter will run off DeviceNet network power, even without batteries installed. Remember to install batteries if you plan to use the Lock and offline viewing features.
Page 3: How To Use This Manual
How to use this manual This is a reference manual for the DeviceNet NetMeter (DN-MTR). For each NetMeter switch position you will find a page explaining the measurements available, and suggested actions and/or remedies if your network is not healthy.
Page 4: Viewing Measurements
- even if the meter is turned off. Resetting Min/Max Measurements The NetMeter is reset (Min/Max and other stored measurements cleared) when the Lock switch is moved to the "Run" position, and when the power switch is turned On while the Lock switch is in the "Run" position.
Page 5 Display 125 250 500 1 Network MAC ID (node #) or NetMeter switch setting number (AutoSearch) 2 Display locked indicator (“lock” switch is on) 3 Measurement displayed is acceptable 4 Measurement displayed is marginal 5 Measurement displayed is unacceptable 6 Battery low - stored measurements may be lost...
Page 6: Bus Errors
Bus Errors NetMeter tracks network data transmission errors in real- time, and lets you know if the error rate is acceptable marginal , or unacceptable . Any error rate greater than zero is undesirable (although your network may still function since CAN automatically retransmits after errors).
Page 7 Bus Errors Thresholds: Error Rate High Fault 15 /s Error Rate High Warn 1 /s What do to when you see Press to identify the device(s) with higher error rates than other nodes. Calculate the ratio of error rate to frame rate of suspect nodes and check for above average ratios.
Page 8 Bus Traffic NetMeter continuously monitors the CAN bit-stream for message traffic. NetMeter reports Bus Traffic as either network bandwidth consumed (including bandwidth consumed by errors/retries) or bus frames per second. Display What it means Current network or node bandwidth utilization.
Page 9 MAX bandwidth much higher than average) Bus Traffic of 0% for a single node means that the node (MACID) has stopped communicating since the NetMeter was plugged in or reset! Bus Traffic deals with these two wires (CANL & CANH)
Page 10: Bus Power
Bus Power NetMeter continuously monitors the DeviceNet bus power quality. Display What it means Current network bus voltage is 17.2V. Minimum bus voltage recorded since NetMeter was plugged in or reset is 17.1V. Maximum bus voltage recorded since NetMeter was plugged in or reset is 17.4V.
Page 11 Bus Power Examples of transients Thresholds: High Voltage Fault 25.0V Low Voltage Warning 14.0V Low Voltage Fault 13.0V High P-P Voltage Fault 10.0V High P-P Voltage Warning 2.0V bus power voltage levels we suggest: Check your power supply for proper installation and correct output voltage under load.
Page 12 Shield Voltage NetMeter measures live, minimum, and maximum DC shield voltage (between shield and V-). Display What it means Current shield voltage is -3.4V. The minimum shield voltage recorded since the NetMeter was plugged in or reset is -3.5V. The maximum shield...
Page 13 Check for shorted or open shield wiring Check that your shield wire is actually grounded correctly (it’s so important you check it twice!) The NetMeter displays “OL” if the shield is not connected (or if the voltage is high). Semiconductor Fab Applications: Disregard...
Page 14 CAN Primer DeviceNet is based on the CAN protocol. A fundamental understanding of CAN will help you take full advantage of the NetMeter’s features and significantly improve your ability to diagnose network problems quickly. CAN messages are transmitted as a difference in voltage between two separate wires, CANH (white) and CANL (blue).
Page 15 Six separate CAN voltage measurements are essential to rapid troubleshooting. The NetMeter accurately measures these voltages at the following switch settings: CANH,R...
Page 16: Common Mode
CMV. Collectively, these intermittent factors are called "noise". Total CMV is critical to network health. NetMeter measures total CMV over time and records the maximum. To measure worst-case total CMV, leave the NetMeter connected to the network for an appropriate period of time (one machine cycle, one shift, one day).
Page 17 CMV High Warning 5.00V Notes About Common Mode Voltage (CMV) NetMeter's CMV measurements are not affected by where on the network you take the measurement. DC CMV problems are typically caused when devices draw more current than expected or when cable resistance is higher than expected (too much cable) or a combination of both.
Page 18 Display What it means Current CANH/L recessive voltage differential is 0.09V. Minimum CANH/L recessive voltage differential since the NetMeter was plugged in or reset is 0.08V. Maximum CANH/L recessive voltage differential since NetMeter was plugged in or reset is 0.09V.
Page 19 NetMeter measures the difference between CANH and CANL for recessive bits on the network, and if the difference is not close to 0 volts, NetMeter indicates a warning or a fault. CANH/L differential recessive voltage...
Page 20 At the beginning of each frame it is possible for several nodes to transmit simultaneously resulting in a dominant differential >3V. NetMeter accurately measures dominant voltage by sampling only when one node is transmitting. A measured dominant differential (single node transmitting) larger than 3V is a clear indication of a network problem.
Page 21 0 (opposite from what you might expect). The bus can only be in the dominant state when a node is actively transmitting. NetMeter measures the difference between CANH and CANL for dominant bits on the network, and if the difference is not within acceptable limits, NetMeter indicates a warning or a fault.
Page 22 CANL wires. However, if the absolute voltage of the signal (measured to the V- wire at any node) is too high or too low, bits may not be received correctly. NetMeter measures each of the key CANH, CANL and Differential voltages, and if the readings are too high or low, NetMeter indicates a warning or fault.
Page 23 The actual network traffic is reported as a percentage of the theoretical maximum, and is called % Bandwidth. NetMeter's measurements include bandwidth lost due to bus errors and retries but most other diagnostic tools only include...
Page 24: Switch Settings
7 hours on fresh batteries.. The Alarm Sound switch (on right) enables and disables the “beep on error/transient” feature. With this feature enabled NetMeter beeps each time a bus error or transient occurs when the selector switch is in the corresponding position.
Page 25: Industry Canada
Certifications LISTED MEASURING AND TESTING EQUIPMENT 1WA4 This device meets or exceeds the requirements of the following standard(s): UL3111-1 Can/CSA C22.2 CAT II 30V This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference and (2) this device must accept any interference received, including interference that may cause undesired...
Page 26 This equipment is neither designed for, nor intended for operation in installations where it is subject to hazardous voltages and/or hazardous currents. Cables The NetMeter is designed for use with the supplied cables or the following Brad Harrison replacement cables: DND-21A-M010...
Page 27: Warranty
SST’s published information on proper installation. The Warranty period for the NetAlert NetMeter for Devicenet is one year from the date of shipment. SST/Woodhead Connectivity will repair or replace, at our...
Page 28: Specifications
All rights reserved. No portion of this document may be reproduced in any form without the prior written permission of Woodhead Canada Limited. NetAlert, NetMeter and SST are trademarks of Woodhead Industries, Inc. All other trade names are trademarks or registered trademarks of their respective companies.