Product Summary
The 1794-VHSC Flex I/O module delivers very high-speed counting for demanding automation tasks. It processes up to two independent input channels at a frequency of 1 MHz. Engineers use this module for precise encoder feedback in motion control and packaging systems.
Theme Selection: Expert Technical Evaluation & Performance Review
Core Counting Capabilities and Input Design
The 1794-VHSC features a robust input architecture for rapid signal acquisition. It offers 2 input channels with 2 groups of 3 inputs per counter. This configuration supports complex encoder modes like quadrature and pulse-train counting.
Input Voltage and Current Specifications
This module operates with a 5V DC input voltage. You can configure it for either 5V DC or 15-24V DC terminations. The input on-state current exceeds 5mA, while the off-state current stays below 0.25 mA. These thresholds ensure reliable noise immunity in industrial environments.
High-Frequency Signal Processing
The modules input frequency reaches up to 1 MHz. This capability allows it to track extremely fast-moving parts or high-resolution encoders. It provides signals to any compatible programmable controller with EtherNet capability.
Output Stage and Power Management
The unit includes 2 isolated groups of 2 outputs each. These outputs support a supply voltage range of 10-31V DC. The electrical rating is 0.5A at 5V DC and 1.0A at 12-24V DC. This design allows the module to drive small actuators directly.
Thermal and Environmental Tolerances
The 1794-VHSC dissipates a maximum of 5.0W at 31.2V DC. Its thermal dissipation is 17.1 BTU/hr at this maximum. It operates reliably in temperatures from 0 to 55 °C. The module also tolerates a 5-95% non-condensing humidity range.
Installation and Isolation Details
You must install the module on a 1794-TB3G or 1794-TB3GS terminal base. It uses a 24V DC external power supply with a 19.2-31.2V DC range. The unit provides 50V isolation between 6 separate areas. Engineers test this isolation at 850V DC for 1 second.
Theme Selection: Step-by-Step User & Installation Guide
Choosing the Correct Terminal Base
Start your installation by selecting the proper base unit. You must use either the 1794-TB3G or the 1794-TB3GS terminal base. This base provides the physical connection for all field wiring.
Connecting the Power Supply
The 1794-VHSC requires an external 24V DC nominal power supply. Ensure this supply stays within the 19.2-31.2V DC range. The module draws 100mA at 24V DC. Always verify the supply voltage with a DMM before connection.
Wiring the Input Channels
Wire your encoders or sensors to the 2 input channels on the terminal base. Each channel uses 2 groups of 3 inputs. Match your wiring termination to either 5V DC or 15-24V DC. Use the correct configuration for your specific encoder type.
Configuring the Output Loads
The module features 2 isolated groups of 2 outputs. Connect your output loads based on the electrical ratings. For 5V DC loads, the max current is 0.5A. For 12-24V DC loads, the max current is 1.0A. Pay close attention to the voltage loss of 0.9V DC at full load.
Setting the Key-Switch Position
The 1794-VHSC uses 1 key-switch position for proper alignment. This mechanical key prevents installing the wrong module type. Rotate the key to the correct position before inserting the module.
Verifying the Flexbus Connection
Once seated, the module draws 75mA at 5V DC from the Flexbus backplane. Check that your backplane power supply can handle this load. The module measures 3.7in x 3.7in x 2.7in when installed on the base.
