Troubleshooting The Transmitter; Device Not Visible On The Network - Honeywell ST700 User Manual

6.2

Troubleshooting the transmitter

Device not visible on the network

If a device cannot be seen on the fieldbus network, the device may not be powered up or
possibly the supervisory or control program is not able to find (or polling) the node address
of that device. See the following table for possible causes and recommended actions.
Possible cause
Device may have a node
address that is within the
"unpolled range" of addresses.
No power to the device.
Insufficient current to the
device.
More than two or less than two
terminators are wired to
fieldbus link.
Insufficient signal to the
device.
Names of parameters are not
visible.
Revision 2.0 FOUNDATION Fieldbus ST 700 Pressure Transmitter User's Guide
Symptoms
Device not visible on the network
Things to check
Verify the following settings:
•
First Unpolled Node
•
Number of Unpolled Nodes
Measure the DC voltage at the
device's SIGNAL terminals.
Voltage must be within the limits.
Measure the DC current to the
device. The DC current must be
within the limits.
Check to see that only two
terminators are present on a link.
Measure the peak-to-peak signal
amplitude. The output must be
0.75 to 1.0 Vp-p.
Measure the signal on the + and -
SIGNAL terminals and at a
frequency of 31.25k Hz.
Missing or incorrect version of
Device Description file on host
computer.
Recommended action
Set Number of Unpolled
Nodes to "0".
If no voltage or voltage is out
of operating limits, determine
the cause and correct it.
If the current is insufficient,
determine the cause and
correct it.
Correct, if necessary.
If the signal amplitude is
insufficient, determine the
cause and correct it.
Check the path to the Device
Description.
Load correct version of DD.
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