Isolated Input
Specification of the isolated GPIO input ports
Isolated Input Simplified schematic
The input port implements an isolated current-sense input.
DC characteristics>
| Parameter | Conditions | Min. | Typ. | Max. | Units |
|---|---|---|---|---|---|
| Differential voltage | -30 | +30 | V | ||
| Input current threshold | 1 | mA | |||
| Differential voltage | @1 mA | 1.5 | 1.65 | 1.9 | V |
| Input current | @(VIN+ - VIN-) = 1.65 V | 1 | mA | ||
| @(VIN+ - VIN-) = 2.5 V | 2 | mA | |||
| @(VIN+ - VIN-) = 5 V | 2.3 | mA | |||
| @(VIN+ - VIN-) = 12 V | 3 | mA | |||
| @(VIN+ - VIN-) = 30 V | 5 | mA | |||
| @(VIN+ - VIN-) < 1 V | 10 | µA | |||
| DC isolation voltage | 250 | V | |||
| AC isolation voltage | 170 | VRMS |
Input Current vs. Input Voltage Characteristics
AC characteristics
| Parameter | Min. | Typ. | Max. | Units |
|---|---|---|---|---|
| Pulse width | 10 | µs | ||
| Pulse rate | 0 | 50 | kHz |
Logical map
The state of the port is reported as follows:
| Input current | Logical State |
|---|---|
| IIN > 1 mA | HIGH |
| IIN < 1 mA | LOW |
| Unconnected input port | LOW |
Compatible drivers and receivers
The following drivers are compatible with the isolated current-sense inputs:
| ● | Totem-pole LVTTL, TTL, 5 V CMOS drivers |
| ● | RS-422 Differential line drivers |
| ● | Potential free contact, solid-state relay, or opto-isolators |
| ● | 12 V and 24 V signaling voltages are also accepted |
Note: The +12 V power supply on the I/O connector(s) can be used for powering drivers requiring a power supply.
Note: No external resistors are required. However, to obtain the best noise immunity with 12 V and 24 V signaling, it is recommended to insert a series resistor in the circuit. The recommended resistor values are: 4.7k Ohms for 12 V signaling and 10k Ohms for 24 V signaling.