Description
The National Instruments PCI-6516 Digital I/O Device, with part number 779082-01, is designed with a watchdog timer that can be configured up to approximately seven minutes, specifically (232 − 1) × 100 nanoseconds. This feature ensures that outputs are set to a user-defined safe state in the event of a failure, system crash, or communication loss, and this state is maintained until the watchdog is disabled, the device is reset, or the PC is restarted. The watchdog lapse signal continues to assert until the watchdog is disabled, providing a reliable safety mechanism.
The device’s output lines consist of photocouplers and Darlington arrays, which require a power supply ranging from 5 V to 30 V (VCC to COM/GND) for proper operation. To recognize a logic high input, a DC voltage of 11 V or greater must be applied, while a logic low is registered with a DC voltage of 4 V or less. It is important to note that DC voltages between 4 V and 11 V fall within an invalid range and will result in an unreliable value.
| Specification | Detail |
|---|---|
| Product Name | National Instruments PCI-6516 Digital I/O Device |
| Part Number | 779082-01 |
| Watchdog Timer | Configurable up to (2^32 − 1) × 100 ns (~7 minutes) |
| Watchdog Functionality | Sets outputs to a safe state upon failure, system crash, or communication loss |
| Safe State | User-defined, maintained until watchdog is disabled, device reset, or PC restart |
| Watchdog Lapse Signal | Continues to assert until the watchdog is disabled |
| Output Lines | Photocouplers and Darlington arrays |
| Power Supply for Outputs | 5 V to 30 V (VCC to COM/GND) |
| Input Voltage for Logic High | ≥ 11 V (DC) |
| Input Voltage for Logic Low | ≤ 4 V (DC) |
| Invalid Input Voltage Range | 4 V to 11 V (DC) |
Question 1: How does the National Instruments PCI-6516 Digital I/O Device maintain a user-defined safe state during system failures, and what voltage range is required for its output lines to function properly?
Answer 1: The watchdog timer in the National Instruments PCI-6516 Digital I/O Device ensures that outputs are set to a user-defined safe state if a system error, crash, or communication loss occurs, maintaining this state until the watchdog is disabled, the device is reset, or the PC is restarted, and the watchdog lapse signal continues to assert as a reliable safety mechanism until the watchdog is disabled.
Question 2: What safety mechanism does the National Instruments PCI-6516 Digital I/O Device employ to maintain a user-defined safe state in the event of a system malfunction, and how is this state upheld until the system is restored?
Answer 2: The National Instruments PCI-6516 Digital I/O Device employs a watchdog timer as a safety mechanism to maintain a user-defined safe state in the event of a system malfunction, crash, or communication loss, and this state is upheld until the watchdog is disabled, the device is reset, or the PC is restarted, with the watchdog lapse signal asserting continuously until the watchdog is disabled to provide a reliable safety measure.
Question 3: What is the role of the watchdog timer in the National Instruments PCI-6516 Digital I/O Device, and how does it behave in the event of a system error or communication failure?
Answer 3: The National Instruments PCI-6516 Digital I/O Device maintains a user-defined safe state during system failures by utilizing a configurable watchdog timer that ensures outputs remain in this safe state in the event of a failure, system crash, or communication loss, until the watchdog is disabled, the device is reset, or the PC is restarted; for its output lines to function properly, a power supply ranging from 5 V to 30 V is required.
Question 4: What is the purpose of the watchdog timer in the National Instruments PCI-6516 Digital I/O Device and how is it configured to ensure safety in the event of a system failure?
Answer 4: The National Instruments PCI-6516 Digital I/O Device employs a watchdog timer that can be configured for up to approximately seven minutes (2^32 – 1 cycles of 100 nanoseconds each) to ensure that outputs are set to a user-defined safe state in the event of a system malfunction, such as a failure, system crash, or communication loss.
Question 5: What safety feature does the National Instruments PCI-6516 Digital I/O Device employ to maintain a user-defined safe state in the event of a system malfunction, and how long can the watchdog timer be configured?
Answer 5: The watchdog timer in the National Instruments PCI-6516 Digital I/O Device is designed to set outputs to a user-defined safe state in the event of a failure, system crash, or communication loss, and it can be configured up to approximately seven minutes (2^32 − 1) × 100 nanoseconds to maintain this safe state until the watchdog is disabled, the device is reset, or the PC is restarted, thereby providing a reliable safety mechanism.
