HART中的Burst-Mode(突发模式)
突发模式是高速的数据传输模式,其模式通常有几个数据源。在数据总线中,突发模式通常变为专为满足一个设备的通道。
辅助材料1:
Burst-Mode is optional for a HART products but is strongly recommended.
HART Burst-Mode supports the publishing of cyclical process data using "Burst" messaging. In this mode, a device is instructed to publish the response to a command continuously without any further Master or Host action.
If a Field Device supports Burst-Mode then all of Commands 103-105 and Commands 107-109 must be implemented. Furthermore, devices implementing Burst-Mode must support at least 3 Burst Messages. Existing, legacy Field Devices updated from HART 5 are allowed to support only one Burst Message.
辅助材料2:(https://www.crifan.com/comparation_among_hart5_hart6_hart7/)
HART7相对于HART5(和HART6)的功能上,主要增加了:
(1)Enhanced Burst Mode
增强的突发传送模式
更适用于高速的无线(wireless)传输,因为其速度是250Kbit/s,而相对有线的(wired)传输速度是1.2kbit/s。
所以,对于有线的,双线回路(two-wired loop)来说,因其必须工作在小于4mA的环境下,更推荐使用HART5的查询(Polling)模式用于诊断信息(diagnositics)。
而对于4-20mA的设备来说,HART5,也已经够用了。