SERIAL NUMBER: 0601XXXXX and up
PCB Issue B, 010-0242-001
REVISION: MAY 2006 pn 888-0242-001
Table of Contents 1.1 Glossary (1)想你的方向
1.2 General Description (1)
1.3 General Characteristics (1)
1.4 Installation and Adjustments (1)
1.5 Theory of Operation (2)
1.5.1 System Description (2)
1.5.2 Input Circuit (2)
1.5.3 MCU Circuit (2)
1.5.4 Output Circuit (2)
1.5.5 Display and Switch Circuit (3)
1.5.6 Power Supply Circuit (3)
1.6 Maintenance (3)
1.6.1 Trouble Analysis (3)
1.6.2 Trouble Shooting Sequence (3)
1.7 Specifications (4)
1.7.1 Construction (4)
1.7.2 Mechanical (4)
1.7.3 Environmental (4)
1.7.4 Electrical (4)下封层
1.7.5 Timing (4)
1.7.6 Connections (4)
1.8 Parts List 5 State of California
Model 242
DC Isolator Unit
Operations Manual
1.1GLOSSARY
A - Ampere
o C - Celsius
Component - Any electrical or electronic device
DC - Direct Current
Firmware – Program code embedded into a microcontroller unit
Hz - Hertz
IC - Integrated Circuit
Jumper - A means of connecting/disconnecting two or more conductive by soldering/desoldering
a conductive wire or by PCB post jumper
LED - Light Emitting Diode
LOGIC - Negative Logic Convention (Ground True) State
mA - milliAmpere
ms - millicond
MCU - Micro Controller Unit or microcontroller unit
MOV - Metal Oxide Varistor
Opto-coupler – An integrated circuit that provides electrical isolation
PCB - Printed Circuit Board
RMS - Root-Mean-Square
s – cond
Schmidtt Circuit – a circuit that provides hysterisis in the threshold
SW – Switch
uF - microfarad
VAC - Voltage Alternating Current
VDC - Voltage Direct Current
1.2GENERAL DESCRIPTION
The Eberle Design Model 242 is a dual channel DC Isolator unit designed to meet Caltrans specifications TSCES 1989, TSCES addendum of July 1991, and TEES August 2002 Chapter 1. The isolator unit occupies one position of a 170 standard input file. The isolator unit card incorporates a double-sided 44 pin edge connector for the connection of power, input, and output signals. Each channel has individual front panel controls for testing the operational mode, and high intensity front panel LEDs which are ud to indicate the output state. Outputs are optically-isolated solid-state transistors.
1.3GENERAL CHARACTERISTICS
Each channel of the Model 242 provides input hysterisis and digital filtering to qualify the input signal. An input signal must meet the minimum pul requirements specified in ction 1.7.5 in order to produce a valid output. The output pul width for both channels can be t to 100 milliconds minimum by installing jumper SEL3.
Both the input and output circuits have been designed for maximum protection from electrical transients. The inputs have been designed to withstand the discharge of a 10 uF capacitor charged t
o +/- 1000 Vdc directly across the input pins, and a discharge of a 10 uF capacitor charged to +/- 2000 Vdc applied through a source impedance of 5 ohms across the input pins or to Equipment Ground. The outputs are protected by a transient clamp diode.
The Model 242 handle asmbly is made of GE Lexan TM Type 121, which is a super durable polycarbonate resin. The design of this asmbly strengthens and protects the whole PCB asmbly much better than conventional metal face plates.
1.4INSTALLATION AND ADJUSTMENTS
Installation of the unit consists of plugging into the appropriate slot of the Input File and connecting the assigned inputs to the proper cabinet terminals. The edge connector is keyed to prevent incorrect installation. Following power-up, a front panel LED test will illuminate both OUT indicators for two conds.
物质和运动的关系
If desired, the output pul width for both channels can be t to 100 milliconds minimum by installing jumper SEL3.
1.5THEORY OF OPERATION
Reference designators shown are for Channel 1. Reference designators for channel 2 are shown in parenthesis.
1.5.1SYSTEM DESCRIPTION
The nsor circuitry can be broken down into ven major blocks. Each “Input Circuit” block contains the electrical transient devices and the input biasing circuit. Although the Model 242 has two DC inputs, a single digital processing ction is ud to process both inputs.
驴用英语怎么说The microcontroller unit “MCU” Block provides the input voltage threshold and input pul width filtering function on both channel 1 and channel 2 DC input circuits.
The MCU then controls the OUTPUT and DISPLAY blocks appropriately. If jumper SEL3 is installed a valid input pul will generate an output pul of 100 milliconds minimum.
The microcontroller also reads the state of the TEST switches on the front panel. If the TEST switch is in the ON (locked) or MOM (momentary) position it will force the output to the asrted (True) state regardless of the input circuit state. The TEST switches are procesd through the MCU for pul width input and output requirements.
Valid output calls are made via optically isolated solid state transistors. Output calls are indicated on the front panel by means of high intensity LEDs labeled “OUT”.
The Model 242 operating voltage is generated by a high efficiency off-line switching power supply. The VDD supply for the microcontroller and display elements results from a post regulated 5 Vdc.
1.5.2INPUT CIRCUIT
Resistors R5, R7, R11, and R12 (R6, R8, R13, and R17) provide the input bias and voltage scaling circuit. The resulting voltage at U8.8 (U8.9) is then procesd by the microcontroller U8. Metal Oxide Varistor RV4 (RV5) provides input electrical transient protection.
1.5.3MCU CIRCUIT
The microcontroller U8 process the input voltages to perform the voltage threshold and pul width filtering functions. All signal processing is performed in the digital domain and controlled by firmware embedded in the microcontroller. This unit does not rely on analog delay, pul, or comparator circuits for processing the input signals.
1.5.4OUTPUT CIRCUIT
The output driver Q2 (Q1) is isolated from both the AC Mains and the internal GND reference of the Model 242 by opto-couplers U6 (U2). CR1 (CR2) provides electrical transient protection for the output driver Q2 (Q1).
1.5.5DISPLAY AND SWITCH CIRCUIT
The LED indicator DS1 (DS2) for the channel output is driven directly from the microcontroller U8. The input TEST switch SW4 (SW5) is read by the microcontroller U8 using strobe U8.19 (U8.18).
1.5.6POWER SUPPLY CIRCUIT
The main power supply is a fully isolated switching design. MOV RV7 provides electrical transient protection. The AC Mains voltage is rectified and charges C3 to a nominal 170 Vdc. Controller U1 drives transformer T1 at approximately 144 KHz to produce an isolated DC voltage at C15, C16, and C17. Inductor L1 and C14 filter the high frequency switching noi. The resulting voltage at VCC is regulated to 19.0 +/- 1 Vdc. The opto-coupler U4 and reference U5 provide the clod loop feedback to the power supply controller U1 for regulation. Regulator VR1 regulates VCC down to 5.0 Vdc for the microcontroller U8.
1.6MAINTENANCE
The Model 242 requires no adjustments or preventive maintenance.
1.6.1TROUBLE ANALYSIS
The following list should be ud to trouble-shoot the Model 242 installation. If the Model 242 unit itlf is suspect, e Section 1.6.2 for a complete internal testing quence.
a.Neither channel responds to DC inputs
a.Power supply fault
The Model 242 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 ret state. In this ca, the unit will appear to be non-functional.
b.Channel does not detect all inputs
a.Input voltage or pul width does not meet the requirements of ction 1.7.4 or 1.7.5.
Verify that the DC input voltage level is less than the DC Inputs True specification.
Verify that the DC input pul width is greater than the Input Pul Width Accept specification.
1.6.2TROUBLE SHOOTING SEQUENCE
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 exercid in probing internal test points.
a.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.
b.Regulated Power Supply
Voltage at test point VDD should be 5 ± 0.2 Vdc.
Possible component faults are: voltage regulator VR1.
生物圈
c.Microcontroller
Waveform at pin 5 of P1 (or U8.18) should be a 2.5 us high to low pul every 1 millicond.
Possible components at fault are: microcontroller U8.
d.Output Circuit
Output signals are procesd by the microcontroller U8 and appear at U8.6 (U8.5) and on the display LEDs but are not appearing at the output pins.
借的英语
Possible components at fault are: opto-coupler U6 (U2), output transistor Q2 (Q1).
1.7SPECIFICATIONS
1.7.1CONSTRUCTION
Printed circuit boards are double sided 2 oz. (56.70 gm.) copper with plated through holes. Circuit boards are coated for environmental protection.
鼎字
1.7.2MECHANICAL
<4.50 inches Width ..........................................................................................................................1.2 inches Depth (excluding handle)........................................................................................6.875 inches 1.7.3ENVIRONMENTAL
Storage -45 to +85 o C Oper
ating -34 to +74 o C Humidity Range (non-condensing).................................................................0 to 95% Relative 1.7.4ELECTRICAL
AC Supply 80 Vac AC Supply .135 Vac AC Supply 2.5 Watts DC Inputs
True (low).....................................................................................................less than 8 Vdc Fal (high)............................................................................................greater than 12 Vdc Optically Isolated Solid State Outputs
True (low, 50 mA).....................................................................................less than 1.5 Vdc Fal (high)............................................................................................greater than 16 Vdc Maximum Leakage Current (high).................................................................less than 1 uA 50 mA Collector 50 Vdc 1.7.5TIMING
Input Pul .less than 5 ms Input
Pul ater than 25 ms 1.7.6CONNECTIONS
Edge Connector mates with connector type Cinch 50-44A-30
PIN FUNCTION
D Input CH 1
E Input CH 1 Common
F CH 1 Output Collector
H CH 1 Output Emitter
J Input CH 2
K Input CH 2 Common
L Equipment
Ground
-
M AC
N AC饿了就胃疼
+
W CH 2 Output Collector
X CH 2 Output Emitter
