Table of Contents
Advertisement
6.0 Functionality
The main function of the Model 923-EDL card is to collect data from several on-board sensors and external
interfaces and store it in the on-board non-volatile flash memory. The data collected can then be used for further
analysis and evaluation of the environment in which the card is installed. The data stored in flash memory is
saved as analog values and further processing is not required to convert raw sensor data into analog values, as
this task is performed by the on-board microcontroller.
The Model 923 also supports in-field programming via the J5 port, which can be used for future firmware
upgrades.
6.1 Serial Diagnostic Interface
Remotely accessible, real-time diagnostic data and status information is available from the 923-EDL via the port
J5. This information can be used to determine current health and to analyze long-term trending of critical
parameters of the system being monitored (e.g. to estimate the remaining life of a Focal rotary product).
Diagnostic and status information is retrieved from the following:
1. Temperature, humidity, accelerometer, ambient light and rotation sensors (details of these sensors are
provided in section 3.4).
2. A bank of analog to digital converters (ADCs), which monitor board voltage rails.
3. Board information which includes serial number (S/N), data code, assembly number, firmware version,
cause of reset and I2C error count.
4. On-board Flash memory information such as memory usage and current write pointer location.
The serial RS-485 interface (connector J5) of the 923-EDL operates in Modbus RTU mode.
6.1.1 Modbus RTU
The user can communicate with the 923-EDL using the Modbus RTU protocol over the serial RS-485 interface
(J5). The default (as-built) settings are shown in the table below.
Table 6-1: Modbus RTU Frame Format and 923-EDL Defaults
Length
Name
(bits)
At least 3.5 character times of silence
Start
28
(mark condition)
Address
8
Station (node) address
Function
8
Indicates the function code
Data + length will be filled depending
Data
n * 8
on the message type
CRC
16
Cyclic Redundancy Check
At least 3.5 character times of silence
End
28
between frames
Note: The default node address can be changed using the sample GUI.
Focal Technologies Corporation
A Moog Inc. Company
Function
Model 923 Data Logger – User Manual
Default Settings
(923-EDL as-built)
28 bits min.
Node 1
Function Code 3: Read Holding Registers
Function Code 6: Write Single Holding
Register
(other codes are not available)
All Modbus registers are 16-bit values
CRC-16-ANSI (a.k.a. CRC-16-IBM)
28 bits min.
Document No: 923-0603-01, Rev. 2
Page 6-1
Advertisement
Table of Contents
