As a professional supplier, Feimu Technology has been deeply involved in the industrial control field for many years. We have recently launched the Allen Bradley 1746-NO8V 8-channel analog voltage output module. We understand that in automation control, the output signal is like a baton, if it is not accurately directed, the actuator's operation will be distorted, seriously affecting production accuracy.
|
Product Name |
Allen-Bradley 1746-NO8V |
|
Type |
Analog Output Module |
|
Number of Channels |
8 Single-Ended Outputs |
|
Output Signal |
Voltage (e.g., 0-10V, 1-5V, depending on jumper configuration) |
|
Resolution |
Typically 14-bit or 15-bit |
|
Backplane Current Load |
Extremely Low (Minimal impact on power supply) |
The Allen Bradley 1746-NO8V module has excellent performance. It has a wide output range and can typically achieve a 0-10 volt voltage output. It also supports various single-polarity and bipolar voltage ranges, suitable for different on-site requirements. Its resolution is extremely high, capable of subdividing thousands of different voltage levels, with maximum control accuracy.
The most crucial point is that it has strong load capacity and sufficient output current. Even if the cable connecting the actuator is longer, the signal will not be attenuated or distorted, ensuring the precise transmission of instructions. At the same time, it has extremely fast response speed. Once the CPU issues an instruction, the module can instantly switch the voltage with almost no delay, perfectly adapting to the control requirements of dynamic industrial processes.
The most distinctive feature of 1746-NO8V is its 8-channel independent output design. Tasks that previously required two 4-channel modules can now be accomplished with just one unit. For the already crowded old electrical cabinets, this is undoubtedly a space-saving wonder. Without the need to expand the cabinet, multiple signal outputs can be achieved.
Another highlight is its "output retention" function, which we particularly appreciate in our practical operations - if the PLC system suddenly loses power or the CPU stops running, the module will maintain the last output voltage value or operate according to the preset safety value, preventing all equipment in the site from suddenly stopping or misstarting, effectively preventing production accidents. As a professional supplier, we supply all brand new products. The appearance is neat and the performance is intact. Once received, they can be directly installed and used.
The Allen Bradley 1746-NO8V is very easy to install. It can be directly inserted into any 1746 slot of the SLC 500 system rack (except slot 0). The wiring is standardized and in line with industrial standards. Engineers familiar with this series of systems can complete the installation and debugging quickly. At the same time, we will provide simple wiring guidance to help you get started quickly.
Daily use does not require complex maintenance. Just check the wiring terminals regularly and avoid loosening. In addition, the product is of high price-performance ratio (Price and Cheap). We have eliminated unnecessary premiums, allowing everyone to obtain high-quality analog voltage output modules at the optimal cost and reduce the project investment cost.
The 1746-NO8V provides voltage outputs with specific drive limits. Exceeding these limits causes voltage drop and inaccurate control.
Output range: 0-10V DC, 0-5V DC, 1-5V DC, ±10V DC. Jumper selectable per channel group.
Minimum load resistance: 1 kΩ per channel. Below this value, the module cannot maintain the voltage. The output voltage drops as current demand increases.
Maximum output current: 5mA per channel. This is sufficient to drive most VFD analog inputs, valve positioners, and chart recorders. VFD inputs typically draw 1-2mA. Valve positioners draw 2-4mA.
Output impedance: Less than 0.1Ω. Low output impedance ensures voltage stability even with varying load currents.
Cable length recommendation: Up to 100 meters with 0.5mm² cable. For longer runs, use 1.0mm² cable or reduce the load. With proper cable selection, no signal degradation occurs.
Field failure example: A customer connected an older valve positioner with a 500Ω input impedance to the 1746-NO8V. The voltage dropped from 10V to 8.5V. The valve never reached full position. Cause: The valve positioner input impedance was below the 1 kΩ minimum. Fix: Added a 500Ω resistor in series to increase the load. The voltage returned to 10V. The valve operated correctly.
The 1746-NO8V uses jumpers to set output ranges. Correct jumper placement is critical for proper operation.
Jumper group 1: Channels 0-3. Jumper group 2: Channels 4-7.
Jumper positions:
Position A: 0-10V DC. Most common range. Used for VFD speed reference, actuator position, and general process control.
Position B: 0-5V DC. Used for older instruments or devices with limited input ranges.
Position C: 1-5V DC. Used for process transmitters that require a baseline offset. This range helps detect open wire conditions (0V indicates a fault).
Position D: ±10V DC. Used for bidirectional motor control or reversing valve positioners.
How to check the current setting: Remove the module from the rack. Open the top cover. Verify jumper positions against your requirements. Reinstall the module.
What happens if the jumper is wrong: The output voltage does not match the PLC value. Example: PLC writes 5V but the module outputs 2.5V. This occurs when the jumper is set for 0-5V but the PLC configuration expects 0-10V. Always match the jumper setting to the PLC configuration in RSLogix 500.
The Allen Bradley 1746-NO8V converts PLC digital values to analog voltage. The relationship between digital value and output voltage depends on the output range and data format.
For 0-10V range with 0-32767 format: 0 counts equals 0V. 32767 counts equals 10V. Each count equals 0.000305V.
For 0-10V range with 0-4095 format: 0 counts equals 0V. 4095 counts equals 10V. Each count equals 0.00244V.
Scaling example: A VFD requires 0-10V for 0-100% speed. The PLC must control the VFD at 50% speed. Output needed is 5V. With 0-32767 format, the PLC writes 16384 counts. With 0-4095 format, the PLC writes 2048 counts.
Programming steps in RSLogix 500: Configure the module in the I/O tree. Select the output range. Select the data format. Use the SCP (Scale with Parameters) instruction to convert engineering values to the output range. Example: Input is 0-100 (percent). Output is 0-32767 (counts). This matches the 0-10V range.
Common programming mistake: Writing a negative value to a unipolar output range. The module ignores negative values and outputs 0V. Always clamp the value to the valid range in the PLC program.
The output hold function is the most important safety feature of the 1746-NO8V. It determines what the outputs do when the PLC stops.
Three user-selectable modes:
Mode 1 – Hold last state: Outputs remain at the last voltage value before the PLC stopped. Use this for processes that cannot tolerate sudden changes. Example: Heater power must not drop suddenly. Holding prevents thermal shock to the heating element.
Mode 2 – Safe state: Outputs go to a pre-set value configured in the module. Use this for processes that have a known safe value. Example: A valve at 0% is safer than a valve at 100%. Set the safe state to 0V.
Mode 3 – Reset to zero: Outputs go to 0V. Use this when zero signal is the safest state. Example: A conveyor system where 0V means stop.
How to configure: Set the module’s dip switches to select the mode. This is done before installation. The switch is located inside the module housing.
Field failure example: A customer had a tank level control application. The PLC dropped offline but the module held the output voltage at 3V. A valve remained partially open. Cause: The customer had not set a safe state. Fix: Configure the safe state to 0V. This closes the valve when the PLC drops. The tank will not overfill.
When to use each mode:
Use Hold Last State for thermal processes where sudden loss of heat causes product damage.
Use Safe State for processes where a known value is safer than any other value.
Use Reset to Zero for safety-critical applications where all outputs must be off when the PLC stops.
The 1746-NO8V has LEDs on the front panel to indicate operational status.
Power LED (green): On when backplane power is present. Off indicates no power to the module or module failure.
Channel 0 LED (green): On when the channel is actively outputting. Flashing indicates configuration error. Off indicates the channel is not used or not configured.
Channel 4 LED (green): Same as Channel 0 but for the second group of channels.
Fault indicator (red): On when the module detects an internal error. This could be a calibration error, a hardware failure, or a configuration mismatch.
Diagnostics checklist:
If the Power LED is off: Check that the module is inserted correctly. Check that the rack has power. Check that the power supply is delivering 5V DC to the backplane.
If the Channel LED is flashing: Check the jumper setting matches the PLC configuration. Check that the data format matches in RSLogix 500. Check that the channel is enabled in the configuration.
If the Fault LED is on: Remove the module. Re-insert it. If the fault remains, remove the module from the rack. Inspect the backplane connector for bent pins. If the connector is clean and the fault still appears, the module may need replacement.
What Feimu does before shipping: Every 1746-NO8V is tested for all LED functions, all output ranges, and the hold function. The module runs through a 24-hour stabilization test before packaging. This identifies early failures before the module reaches you.
The 1746-NO8V requires minimal maintenance. However, these checks prevent issues from becoming failures.
Quarterly checks:
Terminal screw tightness: Check every 3 months. Use a small screwdriver. Give each screw a quarter turn. If the screw moves, it was loose. Tighten gently. Do not overtighten.
Ventilation: Check that the ventilation slots on the module are clear. Dust accumulation blocks airflow. This causes temperature rise inside the module. Use compressed air to clean the slots if needed. Perform this check annually.
Output verification: Check at least once per year. Force the PLC to output 0V, 5V, and 10V. Measure at the terminal block with a multimeter. Compare the readings. The error should be below 0.1V. If the error exceeds 0.2V, the module may need recalibration.
When to replace the module:
- Output voltage does not match the PLC command by more than 0.5V after cleaning and checking jumpers.
- Output voltage fluctuates while the PLC writes a stable value.
- Module is not recognized by the PLC after multiple re-insertions.
- Physical damage to the terminal block or backplane connector.
For older SLC 500 systems, keep one spare 1746-NO8V on hand. The module is still available but older systems often fail unexpectedly. Downtime cost is higher than the module cost.
Q: Can this module be directly compatible with the SLC 500 system?
A: The Allen Bradley 1746-NO8V is specifically designed for the Allen Bradley SLC 500 system. It can be directly inserted into any of the 1746 slots in the rack (except slot 0), without the need for modifying the rack. The installation is simple and quick, and it has extremely strong compatibility.
Q: Can the output voltage range meet the requirements of different actuators? Is the resolution high enough?
A: It supports various voltage ranges such as 0-10V, 0-5V, 1-5V and ±10V. With a 16-bit high resolution, it can divide the voltage into thousands of levels, and can precisely adapt to the control requirements of different actuators.
Q: Is the supply of Allen Bradley 1746-NO8V stable?
A: The product is always in stock. Regular orders can be shipped on the same day of placing the order. For urgent orders, logistics will be prioritized to ensure timely delivery without delaying on-site production.
Q: Can the "Output Stabilization" function effectively prevent production accidents? Will it immediately lose its effectiveness after a power outage?
A: Yes, when the power is cut off or the CPU stops running, the module will maintain the last output voltage or the preset safety value, preventing the equipment from suddenly shutting down or being mistakenly started. This reduces production accidents at the source and ensures on-site safety.
Address
No. 26, Yuhu Street, Encheng Subdistrict, Enping City, Jiangmen City, Guangdong Province, China
Tel
