Honeywell Electronic Remote Temperature Controller T775J - Manual (Page 18)

T775J ELECTRONIC REMOTE TEMPERATURE CONTROLLER
63-2248—4 18
CHECKOUT
After the controller is installed and wired, apply power. Using
the programmed control values, verify device operation after
completing Table 3.
³ As illustrated in the example, record the sensed
temperatures for both Sensor A and Sensor B as
displayed on the controller. Sensor A senses the
temperature for loads 1 and 2. Sensor B senses the
temperature that determines the amount of reset.
· Write the operating mode for each stage in the
Checkout Table (heat or cool).
» Write Sensor A temperature for each load on the
Sensed Temp line.
¿ Write Sensor B temperature in the space indicated in
the Checkout Table.
´ Press Select until Setpoint B is displayed.
² Write Setpoint B in the space indicated in the Checkout
Table.
¶ Determine the reset direction (up or down) from the
Device Programming Worksheet in the Installation
section and enter in the space indicated in the
Checkout Table.
º Determine the reset action (above or below) from the
Device Programming Worksheet and enter in the space
indicated in the Checkout Table.
¾ Plot the programmed on and off (open/closed) values at
which the device will energize and deenergize each
output load by referring to the Device Programming
Worksheet.
µ
Calculate the amount of reset that exists using
Formula 1.
a. Subtract setpoint B from Sensor B and enter the
result as Temp Diff.
b. If the result is negative, reset will occur only if the
Reset Action Switch is set for reset below
setpoint. If the result is positive, reset will occur if
the Reset Action switch is set for reset above
setpoint.
c. Determine if a reset condition exists.
d. If no reset condition exists, On/Off Control Values
have not been changed.
e. Go to step 11.
f. If a reset condition exists, calculate the amount of
reset using Formula 2.
g. Divide Reset Ratio B value by Reset Ratio A
value.
h. Multiply the result in step g. by Temp Diff
(step a.).
i. If Reset Direction Switch is set to increase,
disregard any negative signs and add the amount
of reset calculated in step h. to the on/off values.
j. If the Reset Direction Switch is set to decrease,
disregard any negative signs and subtract the
amount of reset calculated in step h. from the on/
off values.
k. Plot the new values on the appropriate Reset
Load in the Checkout Table.
¸ Verify which loads are energized by using the Checkout
Table. As shown in the example, the display will indicate
which stages are energized in the lower right-hand
corner. (NOTE: If no stages are energized, the words
stage energized will not appear.)
NOTE: If the sensed temperature is between the on and
off temperatures, the load may be either
energized or deenergized. Refer to the Control
Algorithm subsection of Description/Operation
section for further explanation.
¹ If an error message flashes, refer to the description of
these messages in Error Messages subsection. If SF
flashes, check the sensor connections. If they are
properly connected and SF continues to flash, check
the sensor location to assure it is located in an ambient
condition that is within the sensor’s ambient capability
(-40
° F to +220 ° F).
Ƹ If an error message other than SF flashes, the device
cannot be field repaired. Replace the device.
For the Electronic Series 90 output (T775J1019 and
T775J1043), proper output levels can be checked by
measuring the open-circuit voltage between terminals 1(W)
and 2(R):
Minimum (Drive Closed) signal ≤ 0.17 Vdc.
Maximum (Drive Open) signal ≥ 1.7 Vdc.