baxter ARENA - Temperature Monitoring and Primary Temperature Alarm

Arena Service Manual
Figure 6-1. Temperature Control Block Diagram
6.3 TEMPERATURE MONITORING AND PRIMARY
TEMPERATURE ALARM
This system is managed by the I/O and Hydraulics boards. The
temperature monitoring follows steps similar to temperature
control:
1. The operator enters the desired dialysate temperature
through the Touch Screen, and this information is sent to
Single Board Computer (SBC) via the 4-Comm (Touch
Screen) board.
2. The SBC converts the desired dialysate temperature using
the appropriate calibration constant stored in the SRAM in
the Memory board, and sends it to the I/O Controller board.
The calibration gain has a ±12% adjustment range around
the nominal and the calibration offset has a ±5°C
adjustment range. The gains and offsets for the thermistors
are also stored in the memory board, in the nonvolatile
SRAM for later retrieval and use during the Instrument
initialization.
3. A thermistor at the Primary Conductivity Probe provides
the signal for the I/O Controller via I/O Hydraulics Power
6-6 157-1278-913 Rev A
November 2003