Table of Contents
Advertisement
Troubleshooting Four Input Analog Circuit Cards
TROUBLESHOOTING FOUR INPUT ANALOG CIRCUIT CARDS
POSSIBLE CAUSES
1) Jumpers on Analog
Input circuit card
incorrectly set.
2) Analog inputs
connected to wrong
terminals on Analog
Input circuit card.
3) Shunt size is incorrect. Visually inspect shunt to verify that it is the correct
4) Analog input source
to Analog Input circuit
card defective.
5) High impedance or
open input leads
connected to the
Analog Input circuit
card giving the false
reading.
6) Shorted or low
impedance input
leads connected to
the Analog Input
circuit card giving the
false reading.
7) Noise injected onto
the input leads.
8) SCALE FACTOR
attribute incorrectly
set in the analog
channel configuration.
Vertiv™
| NetSure™ LMS Data Processing Unit User Manual (Section 5847) | Rev. ZA
TEST PROCEDURE
Refer to Section 5879 (Installation Instructions) and
verify correct jumper placement for each analog input.
Refer to Section 5879 (Installation Instructions) and
verify correct terminal block connection for each
analog input.
size (full scale millivolts are as desired).
Verify the analog input source for proper reading
going into the circuit card.
Remove input power to the LMS1000. Remove one
input lead at the source. Short it to the other input
lead. Measure the resistance (ohms) between the
input leads at the Analog Input circuit card terminal
block. This value should not be significantly greater
than the sum of any current limit resistors located in
the input leads.
Remove input power to the LMS1000. Remove and
isolate one input lead at the source. Measure the
resistance (ohms) between the input leads at the
analog circuit card terminal block. This value should
be infinite.
If another analog channel appears to operate
correctly, swap the input leads of the analog circuit
card associated with this channel with those
associated with the defective channel. If the problem
now exists on the swapped channel, the problem is
external to the LMS1000.
Log on to the unit. Enter the command CONFIG Ax,
where x is the number of the analog channel giving
the false reading. Verify (and change if necessary) the
scale factor of this channel.
LOOK FOR ...
--
--
--
--
Open current limit fuses
or resistors.
Wrong value current limit
resistors. (49.9 ohm
resistor recommended
when monitoring shunts).
Open input leads.
Poor solder connections.
Poor terminal
connections.
Leads damaged or
pinched.
Poor connection at
terminal block.
Input leads should always
be twisted pairs.
Input leads running with
other leads carrying AC
signals or near electrically
noisy equipment may pick
up noise.
--
523
Advertisement
Table of Contents
