There is no difference! IEC recently renumbered their standards, so 1158 became 61158. The ISA SP50 work has closely paralleled the IEC fieldbus project, and the resulting standards are identical in technical content.
There is no difference! IEC recently renumbered their standards, so 1158 became 61158. The ISA SP50 work has closely paralleled the IEC fieldbus project, and the resulting standards are identical in technical content.