Guralp Systems CMG-SAM - Manual (Page 9)

Operator’s Guide CMG SAM & CMG CRM
2.3 FRONT PANEL LED’s
Access
Disc Status RAM Status
Aux
Com Port Status
Com Port Status
The data input stream LED’s show that the data is arriving to the port. During
the period of valid data the LED is continuously lit.
Aux
This ‘bi-colour’ LED will turn on green when the system receives the ‘ACK’
character from the block just transmitted (indicating that the data was received
correctly by the PC or SAM); or turn red if the system receives a ‘NACK’ (Not
ACKnowledged) from the last transmitted block.
This LED is turned off when the DM starts transmission of the next block of
data. Thus the time that this lamp is on green gives an indication of the amount
of free time available on the link.
RAM Status
A four element binary “bargraph” display is used to indicate the status of the
silicon file buffer. Green LED’s indicate the smallest binary bits (weight 1, 2,
&3) and red is used for the most significant bits (weight 8). For example, 2
green LED’s indicate
3 /
16
full and 1 red LED indicates ½ full.
Disc Status
Another four element binary “bargraph” display to show the relative content of
the SCSI disc, similar to the RAM Status LED’s above. Data are transferred
from the silicon file buffer when it is 15/16th full (all LEDs lit) and data transfer
stops when it is 1/16th full (1st green LED).
Access
This lights red when the SCSI disc is being accessed, ie downloading data from
the silicon buffer.
Issue D March 2001 7