3.2.2 Digital Outputs
The Jackrabbit has four CMOS-level digital outputs, PB6–PB7, PCLK, and IOBEN. Four high-power outputs, HV0–HV3, are also available—HV0–HV2 can each sink up to 1 A (200 mA for the BL1810 and BL1820) at 30 V, and HV3 can source up to 500 mA (100 mA for the BL1810 and BL1820) at 30 V. The BL1820, which does not have RS-485, has one additional CMOS-level digital output, PC0.
HV0–HV2 SINKING OUTPUTS | +K |
|
| Current |
| Flow |
PE[0–2] | |
HV3 SOURCING OUTPUT | |
| +K |
PE3 | Current |
Flow |
Figure 6. Jackrabbit High-Power Digital Outputs
The common power supply for the four high-power outputs is called K, and is available on header J4. Connect K to the power supply that powers the load, which is usually a separate power supply to that used for the Jackrabbit, and must be no more than 30 V because of the power limitations of the resistors used in the sourcing output circuit.
The K connection performs two functions.
1.K supplies power to the sinking/sourcing transistors used in the high-power circuits.
2.A diode-capacitor combination in the circuit “snubs” voltage transients when inductive loads such as relays and solenoids are driven.
