ICP DAS USA I-7521, User Manual

Page: 91 / 148

I-7521/I-7522/I-7522A/I-7523/I-7524/I-7527 User’s Manual,Ver2.5 Aug.2015
91
5.3.17 #**

Description :
This function regards each input module on the network, both digital and analog, to
sample its entire input data immediately and store the data in the internal register of the
module. Later the host computer can read the data individually by using the
read
synchronized data $AA4 command.

Syntax :
#**[chk](CrLf)
#
Delimiter character
* Command character
[chk] 2-character checksum. If the checksum is disabled

no [chk]
(CrLf) End Character

Response : no response

Example : (Assume the AA address value of the I-7521 module is 01)
command: #**(CrLf)
response: no response
command: $014(CrLf)
response: !0117(CrLf)
command: $014(CrLf)
response: !0113(CrLf)
command: $014(CrLf)
response: !0111(CrLf)
What is “synchronized sampling?”
The host computer can only send one command string at a time. If there are two
modules, the host computer must send and receive the commands from module 1
then the commands from module 2 in response,
so there is a time delay between
the two commands
. The “synchronized sampling” command is designed for all input
modules. When the synchronized sampling command #**[CrLf] is received , all
input modules on theRS-485 network will perform the input function at the
same time and store the values into the intend memory of the module.
The host
computer can then send a read synchronized data command $AA4 to read the data
separately.
Orders all modules to perform synchronized
sampling
DI1=DI2=DI3=1
DI1=1, DI2=DI3=0
DI1=DI2=1, DI3=0
For: I-7521/I-7522/I-7522A/I-7523/I-7524/I-7527