American Magnetics 135 & 136 Liquid Helium Level Instruments (CE-Marked) - Manual (Page 48)

36 Rev. 3
Remote Interface Reference
Serial Poll Status Byte
4.2.5 Serial Poll Status Byte
The IEEE-488 serial poll status byte (spoll byte) can be used to obtain
information about the state of the instrument. Bit 7 of the status byte is
reserved for SRQ. The remaining bits are used to provide custom
information as shown in the table below.
Note
The fill mode indication is only accurate if the fill toggle switch on
the front panel is in the AUTO position. There is no remote
indication or control available for the OPEN or CLOSED manual
override selections.
Bit ON OFF
1 (LSB) HI relay on HI relay off
2 A relay on A relay off
3 B relay on B relay off
4 LO relay on LO relay off
5 Fill mode on
(controller output energized)
Fill mode off
(controller output de-
energized)
6 Data ready for this unit No data available
7 Service Request (SRQ) No SRQ
8 Not used Not used
0RGHO 
0RGHO 
0RGHO