COMLI and PP877
Hi, I wonder can COMLI communication protocol be used to communicate data between PM865 HI and PP877. I mean it works but slow. Our ABB support told us that MMS driver for PP877 hasn't yet been published, so this is currently our only solution.
I found in 3BSE035982-511 (Section 5) some info that I would like someone to clarify, please.
1) It says that maximum message size is 512 bits or 32 16-bit registers. What is considered "a message"? Does this 512 bits include 3 added bits (start,parity,termination) or is it 512 bits of pure data? How many messages are transmitted per unit time? What is relationship between "a message" and baud rate? What is "a register"? Are my dint (32 bit) integers split into two registers and sent? Do registers have 3 added bits?
2) I have situation where I need to transfer 912 bool variables and 501 dint variables. Is COMLI capable of doing this in relatively fast manner? So far, PP has very slow response times.
/ih
I found in 3BSE035982-511 (Section 5) some info that I would like someone to clarify, please.
1) It says that maximum message size is 512 bits or 32 16-bit registers. What is considered "a message"? Does this 512 bits include 3 added bits (start,parity,termination) or is it 512 bits of pure data? How many messages are transmitted per unit time? What is relationship between "a message" and baud rate? What is "a register"? Are my dint (32 bit) integers split into two registers and sent? Do registers have 3 added bits?
2) I have situation where I need to transfer 912 bool variables and 501 dint variables. Is COMLI capable of doing this in relatively fast manner? So far, PP has very slow response times.
/ih
Asked 6 years ago
Voted best answer
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In case of COMLI protocol, we can able to transfer 512 bits or 32 16-bit registers in one function block. The above values are pure data. So in your case to transfer 912 bits & 501 dint variables more number of blocks are required which results in slow update rate.
Other possibilty is to Modbus instead of COMLI, which can handle 125 16-bit registers or 2000 bits in one function block. So the number of function blocks will come down and you can get faster update rate.
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