30119-41 Rev. 1.6/02-07
7
A.
The preferred method of checking the
pulse output is to use a McCrometer Model IN16 at-
tached to the pulse output of the TR28-2. The
McCrometer IN16 will count each time the transmitter
sends a pulse.
B.
A voltmeter can also be used to check
the pulse output. Using a voltmeter, on 0 to 5 VDC
scale, measure voltage between the two pulse output
wires when the totalizer count changes. It will display
a pulse voltage every time the totalizer counts. (The
voltage displayed will depend on how quickly your meter
responds.)
If the pulse is present at the instrument, then the prob-
lem is with the instrument. If the pulse is not present,
perform the same tests at the junction box and at the
transmitter itself. If the pulse is present at the junction
box, then the problem is with the communication lines
from the junction box to the instrument. If the pulse is
present at the transmitter, there is something wrong in
the communication lines between the transmitter and
the instrument. If no pulse can be measured, the unit
must be returned to the factory. (See section XI, 1.)
6. COMMUNICATION PROBLEMS
can be so com-
plex it is usually recommended the instrument contrac-
tor or electrical contractor be informed that our trans-
mitters and indicators prove to be good units and the
trouble could be elsewhere. Sometimes it is necessary
to lay another line from the transmitter to instrument
above ground to help prove the lines are at fault prior
to pulling and replacing existing line. Communications
lines should be kept from tangling up in high voltage
lines inside the panel or wiring cabinet. Communication
lines should be shielded cable and not run in same con-
duit as power lines. Sometimes the 115 V A.C. line
used for the instrument can be causing the trouble. It
is suggested the plug from the instrument be tempo-
rarily transferred to another A.C. outlet which is on
another circuit. It has been found a fluorescent light
circuit tied in with the instrument power source, or
faulty parking lot vapor lights can affect the instru-
ments if A.C. wiring is done incorrectly, giving a noisy
A.C. circuit. Make certain the ground is connected to
earth ground.
7. SEPARATION OF SIGNAL AND POWER
wiring
in separate conduits is the traditional precaution; how-
ever, other measures must be taken to minimize the
effects of electromagnetic interference (EMI) and radio
frequency interference (RFI) on the operation of the
instrument. Otherwise, if high level, short duration noise
spikes are permitted to enter the digital equipment, the
noise can be transferred into the systems logic net-
works and can be misinterpreted as signal data, result-
ing in erroneous system operation and other unpredict-
able responses. Potential noise sources:
Relay coils
Solenoids
AC power wires
Current carrying cables
Radio frequency transmissions
