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In the "Protocol Specification for ANSI Type 2 Optical Port" Standard (ANSI C12.18/MC12.18/IEEE 1701), a point-to-point protocol was developed to transport table data over an optical connection. The ANSI C12.18 / MC12.18/IEEE 1701 protocol include an application language called Protocol Specification for Electric Metering (PSEM) that allows applications to read and write Tables. The "Protocol Specification for Telephone Modem Communication" (ANSI C12.21/MC12.18/IEEE 1702) was then developed to… read more allow devices to use PSEM to transport Tables over telephone modems. This standard extends the concepts of ANSI C12.18/MC12.18/IEEE 1701, ANSI C12.21/MC12.18/IEEE 1702, and ANSI C12.19/MC12.19/ IEEE 1377 standards to allow transport of Table data over any reliable networking communications system. Note that in this use of the word, "reliable" means that for every message sent, the sender receives a response at its option: either a positive acknowledgment or an error message. That is, messages cannot fail silently in a reliable network (see discussion of Reliable Stream Transport Service in IPPA [B1]).2 In addition, this standard describes an optionally exposed point-to-point interface between a C12.22 Device and a C12.22 Communications Module designed to attach to "any" network. The terms "C12.22 XXXX" (e.g., C12.22 Device) were introduced by ANSI C12.22-2008. These terms can be interchangeably replaced with the terms "IEEE 1703 XXXX"; i.e., the IEEE 1703 Device is the same as the ANSI C12.22 Device and the IEEE 1703 Communication Module is the same as the C12.22 thiCommunication Module. However, since this standard was originally developed under the auspice of ANSI C12 SC17 WG1, the document terminology is based on C12.22 terms. Furthermore,s standard defines a methodology to capture, translate, and transmit one-way device messages (blurts). read less

定价： 254元 / 折扣价： 216 元

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This document provides specific requirements for field installed sealing between a pressurized system (stream) containing flammable or combustible process fluids which is connected directly or indirectly to an electrical system where a failure could allow the migration of process fluids directly into the electrical system. The basic requirements for electrical safety are not specifically addressed by this standard. The effects of the loss of containment of the process system in terms of risk to… read more the environment and/or personnel health and safety are also not addressed by this document. read less

定价： 56元 / 折扣价： 48 元