Omega Model CYD201/202 User’s Manual
Service 4-3
4.3 PCB
DESCRIPTION
Below is a brief description of major components on the Model CYD201/2
Printed Circuit Board (PCB). See Figure 4-1.
1. Microprocessor/ROM (U10). This integrated circuit is a combination
microprocessor, program memory, and Precision Option Curve (if
present). Note orientation notch in Figure 4-1.
2. Test Point 1 (TP1) – Corresponds to the Shield pin on the rear panel
connector (J4).
3. Test Point 2 (TP2) – Corresponds to the VREF pin on the rear panel
connector (J4).
4. Connector (J3) – 4-pin jumper connection (for Model CYD200-S only).
5. Connector (J4) – Screw terminal connector.
6. Trimpot (R14) – Calibration trimpot. Accessible from rear panel.
7. DIP Switch (S1) – Accessible from rear panel. Selects temperature
units and curve settings. The fourth switch is not used.
8. Connector (J2) – Power jack used to connect an external 24 Volt power
supply.
9. Connector (J1) – 2-pin jumper connection (for Model CYD200-D only).
10. Fuse (F1) – 200 mA, Slow Blow, 5 mm by 20 mm.
4.4 CALIBRATION
Calibrate the unit from the rear panel. Monitor the voltage between VREF
and Shield on the rear panel screw terminals with a good quality high input
impedance voltmeter. Adjust the CAL trimpot for a reading of 2.500 VDC.
Alternatively, a bare PCB may also be calibrated by monitoring TP1 (Shield)
and TP2 (VREF).
Summary of Contents for CYD200 Series
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