Omega CYD200 Series, Руководство пользователя

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Omega Model CYD201/202 User’s Manual
Service 4-1
CHAPTER 4
SERVICE
4.0 GENERAL
This chapter cover General Troubleshooting (Paragraph 4.1), Operating
Software Replacement (Paragraph 4.2), the Model CYD201 Printed Circuit
Board (PCB) (Paragraph 4.3), and Calibration (Paragraph 4.4).
4.1 GENERAL TROUBLESHOOTING
If there is no power, first verify that 24 VAC is present. Next, check the fuse.
Open unit, remove fuse, and test fuse with ohmmeter. Do not rely on visual
inspection of fuse. See Figure 4-1. The fuse rating is 200 mA, Slow-Blow,
5 mm by 20 mm.
Upon power up, the sensor curve displays, where “CU0” = CY7, “CU1” =
CTI, “CU2” = D-Curve, or “CU3” = Precision Option. If sensor connections
are correct, the temperature displays and the decimal point blinks. If there is
a problem, one of two messages display:
“OPEN” = sensor connection is
loose, polarity backward, or not connected; or “SHORT” = wiring is shorted
at some point between unit and sensor.
4.2 Operating Software Replacement
The microprocessor IC (U10) contains the Model CYD201 operating
software. See Item 10 in Figure 4-1. Use the following procedure to replace
the operating software IC.
CAUTION: To avoid damaging the unit, disconnect unit from power supply
before performing this procedure.
1. Disconnect power plug and screw terminal connector from unit rear.
2. Remove four screws attaching rear panel to unit.
3. Note location of PCB(s) in slots. Ensure DIP switch remains attached to
socket.
4. Locate IC U10 on main circuit board. Note orientation of existing
EPROM (circular notch on front of IC).
5. Use IC puller to remove existing IC from socket.
6. Noting orientation of new IC, use IC insertion tool to place new IC into
socket.
7. Slide PCB(s) into appropriate slot and replace rear panel.
8. Reconnect power plug and screw terminal connector to unit rear.