SCP SCIENCE
32
KeyPad
Version 1.0
FIGURE 22: A/D CIRCUIT TEST POINTS AND J9 LOCATION
Legend
1.
2. TP12 (Analog input to CPU)
3. TP13 (Differential voltage)
4. TP7 (5Vdc analog voltage)
5. TP6 (GND analog voltage)
6. TP10 (1Vdc reference voltage)
7. TP11 (RTD supply voltage)
8. TP14 (RTD signal voltage)
9.
J9 header with RTD cable disconnected
(pins 1 to 5)
A/D CONVERSION BEHAVIOR
• If all the previous measurements are correct, make
sure that all the external components or
instruments (snesors,
PROBE
,
Digi
SET, etc) and
interconnection cables are properly connected.
• Reconnect cable J9 to its header and verify if the
system is heating up accordingly and the block
temperature feedback is correct.
CPU SECTION
The CPU section is basically the microcontroler
PIC18F8722, U6 (see fi gure 23 for location)
FIGURE 23: CPU AND REFERENCE VOLTAGES LOCATION
Legend
1. Pin 3 of J1
2. Pin 1 of J1
3. Via to pin 27 of U6
4. Via to pin 26 of U6
5. Via to pin 25 of U6
6. U6, CPU
If anyof the sections 1 to 5 has been verifi ed and
a CPU problem is suspecgted then try the following
sections.
LCD DISPLAY PROBLEM
If the section 1 has been fully investigated and the
system is always returning to the default setup (EN
language, default heating block type etc.), replae the
KeyPad PCB.
Summary of Contents for DigiPREP
Page 61: ...KeyPad Version 1 0 SCP SCIENCE 61 ELECTRICAL SCHEMATIC DigiPREP HT ...
Page 73: ...KeyPad Version 1 0 SCP SCIENCE 73 HEATER VERIFICATION ...
Page 83: ...KeyPad Version 1 0 SCP SCIENCE 83 ...
Page 84: ...SCP SCIENCE 84 KeyPad Version 1 0 ...
Page 85: ...KeyPad Version 1 0 SCP SCIENCE 85 ...
Page 86: ...SCP SCIENCE 86 KeyPad Version 1 0 NOTES ...