Honeywell STT700 STT700, Руководство пользователя

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Revision 1 STT700 Temperature Transmitter
User’s Manual
Page 29
6. Maintenance
6.1. Overview
Maintenance of this transmitter is limited to ensuring that connections, seals and mounting hardware
are tight and secure. There are no moving parts or adjustments, thus, the only reason to open the
housing (where supplied) is to inspect for corrosion or conductive dust entry which could later affect
reliable operation.
WARNING:
The transmitter module itself should NEVER be opened.
6.2. Preventive Maintenance Practices and Schedules
This SmartLine transmitter does not require any specific maintenance at regularly scheduled intervals.
Please take appropriate steps to avoid ESD damage when handling
6.3. Troubleshooting
6.3.1. Troubleshooting with SFC
Troubleshooting the STT700 DE transmitter loop is greatly simplified by connecting the SFC in the
termination area near the receiving instrument. Also connect a digital volt meter (DVM), at the
termination area for the receiving instrument, to confirm a similar signal is coming from the field and
power is available on the two wires of the 4-20 mA loop. This isolates the problem to either field loop
or receiving instrument/power supply/wiring/safety barriers etc. If the original symptom was an
unstable input, it could be a loose connection on the receiving side. Assuming the above confirms a
field loop problem, the likely causes and actions are given below.
For any step the first action is to hook up the SFC to the transmitter and press "ID", then "STATUS".
SYMPTOM SFC MESSAGE/
DISPLAY
POSSIBLE CAUSE CURE
No input or low
input " INPUT OPEN " (with
downscale fail-safe)
"
I/P OUT OF SPEC "
(indicates that the input is
below LRL)
"
HI RES/LO VOLTS " which
indicates an open circuit
loop
Bad sensor wire
connection.
Incorrect operating voltage. Check out field wiring and
connections.
Ensure that the transmitter is
in its voltage operating area.
Verify that the 250 ohms
resistor is in loop.
High input
" INPUT OPEN " (with
upscale fail-safe)
"
I/P OUT OF SPEC "
(indicates that the input is
above URL or below LRL)
Bad sensor wire
connection.
Check field wiring and
connections for partial short
circuit.
Check that the transmitter is in
its voltage operating area and