EDI 242E Panduan Pengoperasian - Halaman 7

Jelajahi secara online atau unduh pdf Panduan Pengoperasian untuk Kelistrikan Industri EDI 242E. EDI 242E 13 halaman. Enhanced dc isolator unit

noise. The resulting voltage at VCC is regulated to 19.0 +/- 1 Vdc. The opto-coupler U4 and

reference U5 provide the closed loop feedback to the power supply controller U1 for

regulation. Regulator VR1 regulates VCC down to 5.0 Vdc for the microcontroller U8.

1.7 MAINTENANCE

The Model 242E requires no adjustments or preventive maintenance.

The following list should be used to trouble-shoot the Model 242E installation. If the Model

242E unit itself is suspect, see Section 1.7.2 for a complete internal testing sequence.

Neither channel responds to DC inputs

Power supply fault

The Model 242E requires a 115 Vac nominal supply. The unit will operate at

voltages as low as 80 Vac, however, an AC Mains voltage below this may result

in the unit entering a reset state. In this case, the unit will appear to be non-

functional.

Channel does not detect all inputs

Input voltage or pulse width does not meet the requirements of section 1.8.4 or

1.8.5.

Verify that the DC input voltage level is less than the DC Inputs True

specification. Verify that the DC input pulse width is greater than the Input Pulse

Width Accept specification.

Apply 115 Vac nominal mains power to AC+ pin J1-N referenced to AC- pin J1-M. Connect

a jumper circuit to the DC inputs J1-D [J1-J] and J1-E [J1-K] to simulate the closure of the

input contacts. The following signal measurements are referenced to test point "GND".

NOTE: internal test point "GND" is isolated from AC-. Care should be exercised in probing

internal test points.

Input Bias Power Supply

Voltage at test point V_UNF should be 19 ± 1 Vdc.

Possible component faults are: controller U1, diodes CR10 and CR14,

transformer T1, inductor L1, or opto-coupler U4.

Regulated Power Supply

Voltage at test point VDD should be 5 ± 0.2 Vdc.

Possible component faults are: voltage regulator VR1.

Microcontroller

Waveform at pin 5 of P1 (or U8.18) should be a 2.5 us high to low pulse every 1

millisecond.

Possible components at fault are: microcontroller U8.

Output Circuit

Output signals are processed by the microcontroller U8 and appear at U8.6

[U8.5] and on the display LEDs but are not appearing at the output pins.

Possible components at fault are: opto-coupler U6 [U2], output transistor Q2

[Q1].

Eberle Design Inc.

Model 242E

Operations Manual

Page 4