Eaton’s Crouse-Hinds Business
Cooper Crouse-Hinds Pte Ltd
No. 2 Serangoon North Ave 5 #06-01
Singapore 554911
tel: + 65 6645 9888
fax: +65 6297 4819
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Parameter
Symbol / Alert
Remedy
Number of
devices on
live list
Low PreAlert
Check for device failed or removed for maintenance.
If latching alarm acknowledge is configured and alert cleared on
acknowledgement this is an indication of intermittent communication. Check:
1.
Trunk cabling, host and trunk JB connections are tight;
2.
For water in trunk or spur cable, junction boxes;
3.
Host operation;
4.
Spur cabling, spur andf device connections are tight;
5.
For water in spur cable or device;
6.
Device operation.
High PreAlert
A device was additionally connected to the bus. This alert may appear for a
handheld communicator (e.g. Emerson 475) if the limit was set to the actual
number of devices. In that case, increase the limit by one to avoid this alert.
Short to
/-ve
(symbol only)
Check:
1. Fieldbus screening is correctly cut back and taped at each end of the fieldbus
device;
2. Fieldbus screen connections are correctly made in Fieldbus Barrier Junction
Box, intermediate junction boxes, in marshalling cabinet, surge protector and
correctly connected to ground;
3. Disconnect portions of cable and check if the short goes away;
4. Verify the fieldbus power supply is isolated from ground;
5. Check for damaged or waterlogged cable, junction box or device.
