Baumer G1-G2-G0-GE-GB-GXxxx - Manual (Page 16)

Manual_ProfibusDPV0_BIDE_EN.docx 16/26 Baumer IVO GmbH & Co. KG
22.11.12 Villingen-Schwenningen, Germany
Alarm signal position error
The alarm signal is triggered by two events:
Code consistency error due to a malfunction in the optoelectronic/magnetic system
Preset value outside the admissible value range
The angular position of the shaft is sampled cyclically via the encoded glass panel. Two
consecutive position values are compared to each other. If the value change exceeds a
certain number of steps, the last position value is implausible.
The encoder sets the Ext_diag. bit and bit 0 to the alarm signal status.
In case of a code consistency error, the Ext_diag. bit is automatically reset after 2.5 s. If a
further event occurs during this time, the period is automatically extended by 2.5 s.
In the event of an inadmissible preset value, the Ext_diag bit remains set until the master has
transmitted the correct value.
Code consistency errors and inadmissible preset values are indicated by the display element
in the bus cover.
Warning signal lithium cell voltage (only multiturn encoders)
If the encoder is receiving no operating voltage, the internal lithium cell supplies the necessary
supply voltage for the part of the circuit necessary for counting revolutions and storing them in
the ASIC. When the operating voltage is switched on, the stored value is read out, the position
change within one revolution is picked up by the optoelectronic or magnetic singleturn system.
Position changes in the OFF status are brought about for example by run-on of the shaft or
subsequent manual adjustment.
The lithium cell voltage is internally monitored. If the voltage drops below the prescribed value,
the encoder internally sets the Diag_ext error bit and indicates the event via bit 5 in the warning
signal. However, the revolution counting and saving functions are only guaranteed for a certain
time when powered by the lithium cell.
Once this period is exhausted, the encoder must be decommissioned or permanently powered
by an external voltage supply.
The amount of time for which the encoder can continue to be operated depends on recognition
of the event.
Status signal already exists at encoder power on.
If the time of first occurrence is not known, the encoder must be withdrawn from service
immediately.
Status signal occurs during operation in the Data_Exchange mode.
Once the status signal is active, the encoder will continue to function for several weeks
without problems before it needs to be exchanged.