The Conspec Universal Transmitter (CX/CN Series) is a micro-controller based electronic sensor designed for gas monitoring, capable of operating as a standalone unit or integrated into larger fixed-point detection systems. It accepts signals from various industry-standard cells, including Electrochemical, Catalytic Bead, Infrared, Photo-Ionization, and Thermal Conductivity, to determine ambient levels of target gases.

Function Description:

The Universal Transmitter provides local display and alarm indication when operating standalone. Alternatively, it can output a 4-20 mA current signal when used as a remote sensor. For integration into a larger system, it can incorporate the 900773 MODBUS protocol 2W 485 communications trunk adapter board.

The device features visual alarm indicators: a green LED blinks once every two seconds for normal conditions. If the first alarm level is exceeded, a red LED blinks once every two seconds. For the second alarm level, the red LED blinks twice every two seconds. An optional 900773 Modbus - Alarm Relay Board can be added, which contains three SPDT relays that activate based on programmable alarm set points. This board also allows for the connection of self-contained or remote audible and visual alarms and enables the activation of control devices during an alarm condition.

User interaction and status indication are managed via a 2-line, 8-character alphanumeric Liquid Crystal Display (LCD) and keypad entry. The standard keypad is a self-contained infrared encoder. The transmitter is temperature compensated across its entire operating range through software, and it supports a simple, adjustment-free one-person calibration feature.

Important Technical Specifications:

Control Voltage: 12-24 Volt DC, approximately 100mA typical load.
Analog Output: 4-20 mA current source standard.
Operating Temperature: -20 to +50 degrees Celsius.
Humidity: 10-95%, non-condensing.
Accuracy: +/- 2% Full Scale.
Repeatability: +/- 2% Full Scale.
Stability: +/- 2% over 24-hour test, full temperature range.
Enclosures: Available in NEMA 4X rated enclosure and NEMA 7X rated Explosion Proof enclosure for Classified Areas.
Wiring: Powered via a 3-conductor 18-22AWG shielded cable. Conspec recommends using an isolated power supply (Clean Power) and placing electrical wiring in conduit.
Modbus Communication (with 900745 board): Standard 2-wire, RS-485, ModBus communication system using 18-22 AWG shielded twisted-pair connection.
- Status LEDs on 900745 board:
  - D1 (Green): Power, ON steady after proper power initialization.
  - D2 (Red): Communication Fault, flashes during power initialization and for communication errors.
  - D3 (Yellow): Data Receive Indicator (RX), illuminates when data is present on RS-485 bus.
  - D4 (Yellow): Data Transmit Indicator (TX), illuminates when a response is sent from the Slave to the Master.
Optional Modbus / Relay Card (900773-24V or 900773-12V): Provides three relay outputs (1st Alarm, 2nd Alarm, Sensor Fail) and RS-485 ModBus communication.
- Relay Ratings: (3) SPDT Rated .5A @ 120VAC, 60W.
- Status LEDs on 900773 board: Power, Fault, RX, and TX for troubleshooting.
Communication Settings (configurable via Command Code 130):
- Trunk Address: 1-247 (Default = 1).
- Parity: 0 - None, 1 - Even (Default = 1), 2 - Odd.
- Baud: 0 - 1200, 1 - 4800 (Default = 1), 2 - 9600, 3 - 19200.
- Contrast: Controls LCD display contrast (0-60, Default = 4).

Usage Features:

Installation: Mount in a suitable location free of drips and drafts, ensuring the detection head points downward. Securely mount using industry-approved methods, adhering to Federal, State, Local Building, and Electrical Codes, including NEC Guide Lines.
Keypad Encoder (911118 Infrared Keypad Encoder - not included): Used for configuration. Command Codes are entered followed by the 'E' (ENTER) key. 'C' (CLEAR) clears entries. Keys '1' and '2' increment/decrement values.
Command Codes:
- 25 (Unlock Monitor): Requires User Password (factory preset to "1"). Unlocks the monitor for 15 minutes, allowing setting modifications.
- 100 (Programmable Parameters): Viewable when locked, modifiable when unlocked. Includes Gas Type, Decimals, Range (for 20mA output), and Span (calibration gas concentration). Note: Factory programmed values, user modification not typically needed.
- 111 (Gas Sensor Calibration): Activates the calibration routine when unlocked.
- 120 (Alarm Parameters): Viewable when locked, modifiable when unlocked. Includes AL1-L/H, AL2-L/H (Alarm Levels), On Delay, Off Delay 1/2 (for alarm relay reset), Alarm Type (8-bit binary word for output relay alarm modes), and Sensor Fail Level.
- 130 (Communication Parameters): Viewable when locked, modifiable when unlocked. Configures ModBus slave address, parity, baud rate, and LCD contrast. A power cycle is required for new settings to take effect.
- 150 (Signal Current Calibration): Calibrates the 4-20mA Analog Output Signal when unlocked. Requires a multi-meter in series with the SIG wire. Adjusts Raw Analog Zero Count (for 4mA) and Raw Count (for 20mA). Typical Raw Count for 4mA is ~190, and for 20mA is ~950.
- 170 (Change User Password): Changes the User Password when unlocked. Requires entering the new password twice.
- 200 (Informational Screens): Displays code version, input voltage, ambient temperature, slope, and live signal values for performance checks and troubleshooting.
- 201 (Informational Screens): Displays gas monitor type and sensor.
Gas Level Indicators:
- Sensor Failure: Detected if the sensor cell's output is diminished or electrical connections fail, driving the signal voltage outside normal limits.
- Temperature Error: Occurs if ambient temperature falls outside the -20 to +50 degree C range.
LED Status Indication:
- Normal Mode: One short green flash, 2-second interval.
- Alarm Level 1: One short red flash, 2-second interval.
- Alarm Level 2: Two short red flashes, 2-second interval.
- Sensor Fail: Alternating red-green, 1-second interval.
- Calibration Span: Constant red.
- Calibration Zero: Constant green.
Output Signal Current:
- Normal Mode: 4.0 to 20.0 mA, linearly proportional from zero to full scale range.
- Sensor Fail: 2.0 mA.
- Temperature Error: 4.0 to 20.0 mA, linearly proportional from zero to full scale range.
- Start Up: 4.0 mA.
- Calibration Mode: Holds last translated output signal level until calibration completion.

Maintenance Features:

Regular Maintenance: Requires evaluation every thirty (30) days for accuracy by applying a known concentration of target gas exceeding programmed alarm levels. The displayed gas value should match the test gas concentration. Any connected warning or control devices should remain connected during this test.
Calibration: Requires calibration every ninety (90) days to ensure accuracy and correct sensor drift.
- Calibration Procedure (Command Code 111):
  1. Unlock monitor (Command Code 25, password "1").
  2. Initiate calibration (Command Code 111).
  3. Apply zero gas to sensor head (green LED on continuously). Wait for raw value to stabilize, then press ENTER. Remove zero gas.
  4. Apply span gas to sensor head (red LED on continuously). Wait for raw value to stabilize, then press ENTER.
  5. "Calibration Done" displays if successful, then monitor returns to normal. "Calibra. Error" displays if rejected (e.g., sensor not fully reacted, sensor passed expected life).
Sensor Replacement: Sensor elements are consumable parts with an expected life. Replacement is required if the sensor can no longer produce a signal within acceptable calibration limits.
- NEMA 4X CN Series: Disconnect power. Open sensor housing part B by pulling downward and twisting until released from part A. Unplug old cell from cell holder card. Plug in new cell and replace housing part B. Calibration is required after sensor replacement.
- Hazardous/Classified Area CX Series: WARNING: Remove power or declassify area before opening sensor housing. Loosen Allen screw and unthread sensor housing part B from part A. Unplug old cell, plug in new cell, rethread housing part B, and retighten Allen screw.
Replacement Parts: Damaged or inoperative parts should be replaced immediately. Consumable parts (filters, pump motors, sensors) should be replaced if reliability is questionable or within their expected life. Conspec provides calibration gases, accessories, and kits.
Repair: Defective or questionable monitors should be returned to Conspec Controls for evaluation and repair. A Return Authorization Number (RA#) is required, obtained by calling (800) 487-8450 Mon-Fri 8am-5pm est. Conspec also offers on-site repair and start-up service.
Modifications: Conspec recommends against modifying the equipment without consulting Conspec Technical Services, as this could result in unsafe operation and void the warranty.
Contaminant/Small Particulates Effects: Dust, coal fines, and rust can block gas flow into the sensor chamber. Preventive measures, such as PTFE Hydrophobic disc filters, should be taken to avoid clogging the sintered metal filter.

Conspec Controls CX Series - Page 17

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