How do I wire SLC loops on the iO64 for Class A and Class B?

The iO64 supports one SLC loop for up to 64 addressable devices, which can be wired as Class B (Style 4) or Class A (Style 6 or 7) using the iO-SDC1 loop controller card (Page 22, 241) [1].

Wiring Configurations

• Class B (Style 4): Connect the circuit from the loop card primary (PRI) terminals to the devices in a daisy-chain. T-taps are permitted with a maximum of 63 T-taps allowed (Page 25, 241) [1].

• Class A (Style 6 or 7): Connect the circuit from the loop card primary (PRI) terminals through the devices and return the end of the circuit to the loop card secondary (SEC) terminals (Page 26) [1].

SLC Specifications

• Wire Size: 12 to 18 AWG (0.75 to 2.5 mm²) (Page 243) [1].

• Limits: Maximum 66 ̦ total resistance and 0.5 μF maximum capacitance (Page 25) [1].

• Isolators: Maximum of 64 isolators (bases or modules) per loop (Page 25) [1].

Programming Steps

1. Press the Menu button and select Programming.
2. Select Advanced Program and enter the Level 2 password.
3. Select Loop Class.
4. Choose the loop and select either Class A or Class B.
5. Select Save (Page 129) [1].