Rev. 1.7 (March 2014) 4 © DLP Design, Inc.
Setup Commands (Remembered Until Power is Cycled)
`
0x60 Return ASCII Default setting; nothing returned (Accent Grave character just left of the
1 key)
\
0x5C Return Binary Nothing returned
L
0x4C Set °F Default setting; nothing returned
;
0x3B Set °C Nothing returned
Ping Command
‘
0x27 Issue Ping Q (0x51) will be returned if the DLP-IO8 is found on the selected port
(Apostrophe character just right of the ; key)
Note 1 – Data is returned in either the form of ASCII characters (ex: 1.25V, 78.2°F) or binary (raw data)
depending upon the current mode. The power-up default mode is ASCII mode such that data is easily read
using a terminal emulator program.
Note 2 – Requires DS18B20 digital temperature sensor (purchased separately). See Section 7.0 of this
document for connection details.
7.0 TEMPERATURE
Up to eight DS18B20+ digital temperature sensors can be connected to the DLP-IO8. For best performance,
use Cat 5 type computer cable to connect the sensors to the DLP-IO8. Two pairs of wires in the Cat 5 cable are
required for the connection. The first pair is for Power (5V) and Ground, and the second pair is designated as
Data and Ground. In addition, a pull-up resistor is required for the data line of approximately 1.5K Ohms.
Figure 1 shows an example of this connection using I/O Channel 1:
1. GND
2. DATA
3. VCC
Pin 1
DS18B20
DLP-IO8
5V 1 2 3 4
5 6 7 8 GND
1
.
5
K
O
h
m
FIGURE 1
The first time temperature data is requested, a value of 999.99° (0xFF x 2 if in Binary Mode) is returned.
Subsequent reads will return valid temperature data if a temperature sensor is properly configured and
connected to the specified I/O port. If no sensor is connected, a Temperature command will always return
999.99°.
Note 3 – Cat5 cable lengths of greater that 100 feet may require a pullup resistor value of less than 1.5K Ohms
in order to achieve usable rise times at the sensor. The minimum safe resistance for the pullup resistor is 240
Ohms.
