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
voltage recorded
since the NetMeter
was plugged in or
reset is -3.2V.
x1
x2
V
250
V
250
MIN
V
250
MAX
5
12
Thresholds:
High Voltage Fault
High Voltage Warning
Low Voltage Warning
Low Voltage Fault
1.0V
0.3V
-4.0V
-5.0V
About DeviceNet Shield Votlage
The DeviceNet specification requires that the shield and
V- be connected together, and both to earth ground at
the power supply. This has the following effects:
A correctly connected shield has no current flow in it
and is at the same voltage (grounded power supply
V-) throughout the system.
Current flow in V- causes a voltage rise in V-
Rising V- voltage causes an apparent negative shift in
the shield voltage when measured relative to V-
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Since the maximum voltage drop in V- is 5V, the
negative shift in shield voltage is between -5V and 0V
Systems connected in accordance with the DeviceNet
installation guidelines (except flat media) have a
"normal" shield voltage between -5V and 0V
