Functional Scope Of Global Functions, PSM, Function - GF54.21-D-3009P
MODEL 906 with CODE ED5 (Parameterizable special module (PSM)) with CODE XM0 (Facelift)
MODEL 906 with CODE ED8 (Preinstallation for parameterizable special module (PSM)) with CODE XM0 (Facelift)
Parameterizable undervoltage detection
The parameterizable undervoltage detection makes it possible to make the functions of the PSM control unit conditional on the on-board power supply voltage.
The thresholds and times can be set under "Global functions - Properties".
This undervoltage detection does not cancel out the function of the hardware undervoltage detection in the PSM control unit, instead it should be seen as a configurable add-on. During evaluation of the on-board electrical system voltage, the system always falls back on the higher of the two voltage values which are applied to the two circuit 30 connections of the PSM control unit.
This ensures that undervoltage detection remains functional even if one of the connections fails.
Three modes are defined for global undervoltage (see picture, page 3):
- "Normal"
- "Undervoltage detected"
- "Undervoltage aborted"
In the "Undervoltage detected" mode, only the "PSM signal:
Undervoltage detected" signal is set to "1" in the signal pool. The functions or outputs parameterized according to the undervoltage are only deactivated in the "Undervoltage aborted" mode. The voltage thresholds as well as times for the switchover between the various modes can be parameterized.
Here, 0 s can, of course, also be specified for the times (e.g. between "Undervoltage detected" and "Undervoltage aborted"). The signals listed in the following table are generated.
| Signal | Remarks |
|---|---|
| 11B9 (Abort due to parameterized undervoltage) | Set if the status changes following "Undervoltage abort". Used as a condition in the case of outputs with parameterizable dependence on the vehicle status. |
| 1274 (Parameterized value for undervoltage UNDERSHOT) | Set if the status changes following "Undervoltage detected". |
The correlations for detection of the global undervoltage and the different effects on the PSM control unit are shown in the following status diagram.
Parameterizable run-on time
The run-on time of the PSM control unit can be set in minutes via menu item "Global functions - Properties". If "0" is set, the run-on is deactivated. The run-on time progresses when the vehicle is locked via the transmitter key. If the vehicle is unlocked, the run-on time is reset to the parameterized value.
After the expiration of the parameterized run-on time the PSM control unit can change to rest mode, if it is not kept awake by other conditions, e.g. individual discrete outputs are active.
During the run-on time, all functions of the PSM control unit can still be operated, provided that they do not require information from CAN-B.
Parameterizable keeping awake function
The PSM contains a function module which can be used to keep the PSM awake. This module can be activated via menu item "Global functions - Properties".
Thus it is possible to prevent a rest mode of the PSM control unit although all the internal conditions required for this are met. This is important in the case of functions that require a continuously active PSM control unit and for which the time limit for the normal run-on of the PSM control unit is not sufficient.
In the event of an incorrect application the PSM control unit cannot change to rest mode, this leads to an increased quiescent current.
To activate the function, the parameter "PSM function" Keepawake of "PSM" control unit must be set to "ACTIVATED".
After this the function can be switched on with an arbitrary bit signal from the signal pool (e.g. programmable logic controller (PLC) output, discrete input).
To do so, the corresponding signal must be assigned to the internal input "Waking of PSM control unit" via the "Signals" menu item.
| Parameterizable special module (PSM) control unit component description | GF54.21-D-5005P |