B&B Electronics 232DTT Manual - Digital Thermometer
232DTT1795 Manual
Chapter 2
3
B&B Electronics -- PO Box 1040 -- Ottawa, IL 61350
PH (815) 433-5100 -- FAX (815) 434-7094
Chapter 2. 232DTT Functions
Digital Thermometer
The 232DTT continuously measures temperature, with a
new measurement completed once per second. When a Read
Temperature command is received, the DTT immediately reports
back the result of the last measurement completed.
Programmable Thermostat
The 232DTT also functions as a thermosta t. Two non-
volatile registers can be programmed. The high threshold register,
TH, is programmed using the !0SH command. The low threshold
register, TL, is programmed using the !0SL command. A complete
command description can be found in Chapter 4. Thermostat
operation is a continuous background function. As long as the unit is
powered, the thermostat outputs will be serviced.
Three open collector outputs provide thermostatic controls.
These outputs are current sinking (low) when on, high impedance
(high) when off.
1. T
HIGH
- Turns on when the temperature equals or exceeds the
user programmed TH register.
2. T
LOW
- Turns on when the temperature is equal to or less than
the user programmed TL register.
3. T
COM
- Turns on when the temperature equals or exceeds the
TH register and turns off when the temperature is equal to or
less than the TL register. This output allows the user to program
any amount of hysteresis.
Remember, these are open collector outputs. They do not
source any current (similar to a contact closure to ground). For
example, to drive a relay with a 12VDC coil with the TCOM output,
connect as follows:
1. Connect +12Vdc to one side of the relay coil.
2. Connect the other side of the coil to the TCOM output.
3. Connect the ground of the 12V supply to the GND terminal
block.