Allen-Bradley HI-1756-2DF ControlLogix Pulse Frequency Input Module
$123.00
$320.00
Description
Allen-Bradley HI-1756-2DF ControlLogix Pulse Frequency Input Module
Configured for high-speed pulse measurement in a ControlLogix chassis, the Allen-Bradley HI-1756-2DF processes two independent frequency inputs for controller data acquisition.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | HI-1756-2DF |
| Brand | Allen-Bradley |
| Manufacturer | Rockwell Automation |
| Series | ControlLogix |
| Module Type | 2-channel pulse frequency input module |
| Number of Inputs | 2 independent channels |
| Input Frequency Range | 1 Hz to 250 kHz per channel |
| Input Signal Types | Magnetic pick-offs, open collectors, TTL, 24 VDC pulse signals |
| Input Voltage Range | 0.2 V to 30 V peak-to-peak, channel and signal type dependent |
| Chassis Location | Any slot in a ControlLogix 1756 chassis |
| Backplane Current, 5 VDC | Approximately 250 mA |
| Backplane Current, 24 VDC | Approximately 3 mA |
| Power Dissipation | 3.5 W maximum |
| Isolation Voltage | 500 VAC continuous, channel-to-backplane |
| Terminal Block | 1756-TBCH or 1756-TBS6H, 36-pin |
| Power Consumption | 3.5 W maximum power dissipation; backplane current as specified above |
| Frequency Measurement | High-speed pulse frequency processing |
| Data Processing | Frequency and pulse signal processing independent of the main controller scan time |
ControlLogix High-Speed Pulse Processing
The 1756-2DF provides two electrically independent input channels for high-frequency pulse acquisition. Each channel accepts pulse signals from magnetic pick-offs, open-collector outputs, TTL sources, or 24 VDC pulse devices.
The specified measurement range extends from 1 Hz to 250 kHz per channel. Therefore, the module can process frequency signals associated with flow measurement, turbine meters, tachometers, and velocity feedback applications.
The module communicates processed measurement data through the ControlLogix 1756 chassis backplane. Its dedicated pulse processing reduces dependence on the main controller scan interval for high-speed input acquisition.
The module uses approximately 250 mA from the 5 VDC backplane supply and approximately 3 mA from the 24 VDC backplane supply. Maximum power dissipation is specified as 3.5 W.
Frequently Asked Questions (FAQ)
Q: How many pulse input channels are provided by the 1756-2DF?
A: The module provides two independent pulse frequency input channels.
Q: What frequency range can each input process?
A: Each channel supports an input frequency range from 1 Hz to 250 kHz.
Q: Which terminal blocks are specified for the module?
A: The supplied data specifies the 1756-TBCH and 1756-TBS6H 36-pin removable terminal blocks.
Field Installation Guidelines
- Install the module in an available slot within the specified ControlLogix 1756 chassis.
- Verify the selected field device output type before connecting it to either pulse input channel.
- Confirm the signal voltage remains within the specified 0.2 V to 30 V peak-to-peak range for the applicable input type.
- Route pulse signal wiring separately from high-current motor, contactor, and variable-frequency drive conductors.
- Use shielded signal cable where electromagnetic interference could affect pulse waveform integrity.
- Terminate cable shields according to the plant grounding architecture and avoid creating unintended ground loops.
- Maintain correct polarity and terminal identification for each independent input channel.
- Verify the installed terminal block type before field wiring, using either the 1756-TBCH or 1756-TBS6H specified for this module.
- Check the ControlLogix chassis power budget against the approximately 250 mA 5 VDC and 3 mA 24 VDC backplane requirements.
- Inspect pulse waveform quality during commissioning when operating near the upper frequency range.
- Keep pulse wiring physically separated from noisy switching circuits to reduce false transitions and frequency measurement errors.
Features
Minimum Order Quantity (MOQ)
We welcome bulk orders and have a minimum order quantity of just one unit.
Certificates and Documentation
Upon request, we can provide all necessary documentation, including Certificates of Origin/Conformance and other required export documents.
Delivery Time
For items in stock, we aim to deliver within 1-3 days after payment confirmation. Items with specified lead times will be delivered according to the quoted schedule.
Payment Methods
We accept 100% T/T (Telegraphic Transfer) payment before shipping. For items with lead times, a 30% deposit is required upfront, with the remaining 70% due before shipment. For RMB transfers, please contact us if you have an agent in China.
Warranty
We offer a standard one-year warranty on all new and original items. If you require an extended warranty, please contact us for additional cost details.
Refund and Return Policy
Your satisfaction is important to us. If you need to return an item, it must be done within 30 days of the order date. The product must be unused, unopened, and in its original packaging with all accessories included. Refunds are processed within 5-7 business days after we receive the returned item. Please note that shipping and related charges are non-refundable.
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