Serial Response Speed
The sensor recalculates the distance measurement every 12 ms. This is not a moving average. A new average is calculated for the
previous 12 ms of data.
With the SSI output, the data can be read every 1.4 ms (possibly the same reading for 8 or 9 readings, followed by a change). For the
most accurate
prediction
of the target
location,
take a sample at the 1.4 ms read-rate of the SSI and determine when the change
happens. In the worst case, the data is for the average target
location
and over the previous 12 ms, plus a 1.4 ms delay. For example,
the 12 ms average was changed just
after
the previous read had started.
RS422 Protocol
RS422 serial interface commands have this structure: <STX><Command><[Data]><EOT>. The sensor responds to the commands in three
different
ways:
• <NAK>—The command was not recognized or the data is outside the limit values.
• <ACK>—The command was recognized and executed. The command requires no response data.
• <Data>—The command was recognized. The requested data was sent.
Definitions
STX
Start transmission (hex 02 or CTRL B)
EOT
End of text (hex 04 or CTRL D)
NAK
No acknowledgement (hex 15 or CTRL U)
ACK
Acknowledge (hex 06 or CTRL F)
Command
3-digit command (ASCII text)
[Data]
Whole numbers (ASCII text)
Note: In ASCII text (C [Data]), spaces and uppercase/lowercase
letters
are ignored.
RS422 Cable
The RS422 interface is a reliable, serial interface in full duplex mode with transfer rates up to 10 MBaud. The maximum cable length is
1,000 m (4,000
ft).
The shielded cable is connected to the sensor connector and the ground terminal of the control cabinet.
RS422 User Commands and Their Meanings
Command
Data to LT7
Data from LT7
Meaning
GAP
All parameters in text format: LT7 $Revision x.xx$
Get All Parameters (all sensor parameters are displayed): sensor
software
revision (number)
Pilot Laser Status
Pilot laser status (ON/OFF/xx seconds ON)
Serial
settings
Serial
settings
Discrete Output Q1
settings
Discrete Output Q2
settings
•
Discrete output
condition:
◦
ON: output high
◦
OFF: output low
•
Output mode
•
Limit 1
setting
•
Limit 2
setting
•
Hysteresis
•
Invert status ON/OFF
Analog Output QA
settings
Analog output
condition
(diffuse
sensors only):
•
Value 0 to 4095
•
Limit 1
setting
•
Limit 2
setting
•
Invert status ON/OFF
Output status
Output unit of measure: mm or one- hundredth of one inch (10 MIL)
Offset
status
Offset
setting
(mm or one-hundredth of one inch)
Password
setting
Password: enabled or disabled
Error status
Error status
L-GAGE
®
LT7 Long-Range Time-of-Flight Laser Sensor
P/N 120244 Rev. C
www.bannerengineering.com - Tel: +1-763-544-3164
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