Delta AS Series Programming Manual page 256

Ch a pt er 4 Ins tr uc t i on S tr uc t ur e
When VarBit1 in FB0 is ON, HCPoint1 (HC0) is ON.
Network: When StartBit[1] is ON, the address of CVar1 is transmitted to HCPoint1 in FB0.
When VarBit1 in FB0 is ON, HCPoint1 (CVar1) is ON.
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