The following steps for complete checkout and testing
of a W7620 are described fully below. The procedures
are as follows:
1.
Check W7620 installation and wiring, including
power to the W7620.
2 .
Start-up W7620 (connect S7610 POT or
ZM7601/ZM7603 software) and assign a network
node address and application (even when using
device in a nonnetworked application). Refer to
W7620 Application Manual, Form 63-4220.
3. Test analog and digital input points
4. Test analog and digital output points.
5. Verify parameter point values.
1 .
Verify that the connections between the W7620
and peripheral equipment are secure.
2 .
Verify that grounding is correct in accordance with
GROUNDING in this
guide as follows:
a.
Verify that each W7620 case is grounded
when the W7620s are powered from
individual transformers.
b.
Verify that all W7620 cases are grounded
when the W7620s are powered from a
c - o n transformer.
c.
Verify that if the application calls for grounded
transformer secondaries, that the grounded
side is connected to earth-ground on the
W7620 (TR earth-ground).
d .
Verify that neither of the CNAP network wires
is grounded or connected to the 24 Vac wires.
e.
Verify that the polarization of the CNAP
network wires is correct, positive to positive
and negative to negative in alI cases.
3 .
Verify the CNAP network termination and biasing
resistors are installed in accordance with 47640
Network Interface Unit specification sheet
(63-4290).
4 .
Turn on power and verify that each W7620 has at
least 20 Vac at Terminals TR and TR
earth-ground.
Testing physical points requires either the actual sensor
be at a known value or digital state, or that a simulated
known value or digital state be applied to the input point
terminals. In the case of physical output points, the output
condition of the controlled equipment must be known,
or the output terminals of the W7620 can be measured
with an indicating device or meter. The Hardware
Configuration Data table shows all of the possible physical
points with terminal designation and use. The General
Guide for Input/Output Point Testing table can be used
to determine what can be used to provide inputs and
what to use to measure outputs.
Input Point lest Procedures
1.
Read point value through the S7610 POT or the
ZM7601/ZM7603 software to verify approximate
analog value or digital state. If the data is
acceptable, proceed to the next point.
2 .
For analog points that display FA (sensor failure)
next to the engineering unit:
a.
Provide a known measurable value to the input.
b.
Compare the input point value displayed on
the POT or ZM7601/ZM7603 software with
the known value.
c.
If the difference between the two values
exceeds the acceptable range, isolate the
problem by taking a measurement at the
input source, the conductors (e.g., cable,
wire), and the W7620.
Example:
The following is the procedure for input
Point 1 (SPACE TEMP).
1 .
Measure the input space temperature in degrees
Fahrenheit with another source, such as a
thermometer, near the actual sensor.
2 .
Verify that the S7610 POT or the
ZM76Ol/ZM7603 software value reads the
expected temperature.
3 .
If the accuracy of the measurement is in question,
measure resistance supplied by the sensor at the
Space Sensor itself to fmd sensed value Terminal
