User's Manual
PCS3_HD_v01.000-03
Confidential / Preliminary
Page 30 of 101
2013-10-21
PCS3 Hardware Interface Description
3.3 Power-Up / Power-Down Scenarios
3.3.5.1
Thermal Shutdown
The board temperature is constantly monitored by an internal NTC resistor located on the PCB.
The values detected by the NTC resistor are measured directly on the board and therefore, are
not fully identical with the ambient temperature.
Each time the board temperature goes out of range or back to normal, PCS3 instantly displays
an alert (if enabled).
•
URCs indicating the level "1" or "-1" allow the user to take appropriate precautions, such as
protecting the module from exposure to extreme conditions. The presentation of the URCs
depends on the settings selected with the AT^SCTM write command:
AT^SCTM=1: Presentation of URCs is always enabled.
AT^SCTM=0 (default): Presentation of URCs is enabled during the 15 second guard period
after start-up of PCS3. After expiry of the 15 second guard period, the presentation will be
disabled, i.e. no URCs with alert levels "1" or ''-1" will be generated.
•
URCs indicating the level "2" or "-2" are instantly followed by an orderly shutdown. The pre-
sentation of these URCs is always enabled, i.e. they will be output even though the factory
setting AT^SCTM=0 was never changed.
The maximum temperature ratings are stated in Section 6.2. Refer to Table 8 for the associated
URCs.
Table 8: Temperature dependent behavior
Sending temperature alert (15sec after PCS3 start-up, otherwise only if URC presentation enabled)
^SCTM_B: 1
Caution: Board close to over temperature limit, i.e., board is 5°C below over
temperature limit.
^SCTM_B: -1
Caution: Board close to under temperature limit, i.e., board is 5°C above under-
temperature limit.
^SCTM_B: 0
Board back to uncritical temperature range, i.e., board is 6°C below its over- or
above its under temperature limit.
Automatic shutdown (URC appears no matter whether or not presentation was enabled)
^SCTM_B: 2 Alert: Board equal or beyond over temperature limit. PCS3 switches off.
^SCTM_B: -2 Alert: Board equal or below under temperature limit. PCS3 switches off.
The AT^SCTM command can also be used to check the present status of the board. Depending
on the selected mode, the read command returns the current board temperature in degrees
Celsius or only a value that indicates whether the board is within the safe or critical temperature
range. See [1] for further instructions.