| Number of points on modules |
16 or 32, depending on module |
4 |
| Isolation and fusing |
16-point input modules: Each point is optically isolated from other points on the module.
32-point input and output modules: The module is divided into four groups of eight points. Groups are isolated from each other, but points within a group are not isolated from each other. Groups must be externally fused |
Input modules: Each point is optically isolated from other points on the module.
Most output modules: Points are not isolated from each other. Points share a common fuse. For isolated modules, see the SNAP Digital Ouput Modules Data Sheet (form #1144). |
| Status LEDs |
None; use the handheld OptoTerminal-G20 for module diagnostics and commissioning, or for 32-point modules, connect to an optional breakout rack. |
One for each point, located on top of module |
| Polling time from I/O processor to module1 |
2–30 ms typical2 |
0.5–2 ms typical2 |
| Module turn-on/off time1 |
16-point input modules: 15–20 ms
32-point input modules: 6 ms
Output modules: 100 microseconds |
Varies by module. Examples:
- SNAP-IDC5-FAST: 25 microseconds
- SNAP-IDC5: 5 ms turn-on, 15 ms turn-off |
| Input latching |
Yes |
Yes |
| Counting on digital input modules |
Counting occurs on the module.3
Counting is available with SNAP-PAC-R14, SNAP-PAC-EB15, and SNAP-PAC-SB1 processors.
Counting speeds:
- On 32-point modules, 0–50 Hz @ 50% duty cycle
- On 16-point modules, 0–25 Hz @ 50% duty cycle
(Speed depends on module; see specifications for each part number.) |
High-speed counting occurs on the I/O processor (brain or on-the-rack controller) and can be configured for any point. (High-speed counting is available on SNAP-PAC-R14, SNAP-PAC-EB15, and SNAP-PAC-SB1 processors.) Counting speed varies based on the processor and the speed of the module. |
| Watchdog timer |
I/O processor firmware 8.1 and higher, yes.
Firmware 8.0 and lower, no. |
Yes |
| Pulse generation |
Yes |
Yes |
| On-pulse, off-pulse, and period measurement |
No |
Yes |
| Frequency |
No |
Yes |
| Totalizer |
No |
Yes |
| Digital events |
I/O processor firmware 8.1 and higher, yes.
Firmware 8.0 and lower, no. |
Yes |
1 Actual turn-on and turn-off times equal the polling time plus the module time.
2 Polling time varies based on the SNAP I/O processor (brain or on-the-rack controller), processor configuration, and Ethernet host communication activity.
3 The high-density digital module uses a 16-bit counter, but the processor used with the module accumulates counts to 32 bits by periodically getting and clearing the module’s counts and adding to current values. Update time varies based on number of modules and Ethernet communication demands.
4 Including SNAP-PAC-R1-B.
5 Obsolete part |