BIRD THRULINE 4021, Instruction Book

Page: 33 / 62

IEEE-488 GPIB Interface
23
T riggers (Tx)
Function
Selects the condition which will trigger a reading (see Figure 18).
Remarks
Failure to trigger device before requesting a reading will lock the bus.
T1 halts the bus until a reading is available.
T0 and T1 do not set the measurement complete SRQ.
T2, T3, T4, and T5 set a SRQ when the measurement is complete.
Fastest reading rate is 2.4 readings/second; slowest is 1 reading/sec.
SRQ M ask (Mxx)
Function
Selectively masks status bits to prevent unwanted service requests.
Set xx to the sum of the binary values of the desired SRQ trigger bits.
For example, M12 would set the SRQ for both operation complete and
underrange (values 8 and 4). Set xx to “00” to never generate an SRQ.
Remarks
If a status bit is masked (bit set to 0), SRQs won’t be generated for
that condition.
Figure 18
Trigger Conditions
Command Trigger Condition
T0
Continuous on talk
T1
One shot on talk
T2
Continuous on GET
T3
One shot on GET
T4
Continuous on measurement command
(FC,FD, RC, RD, SW, RL, MN, MX)
T5
One shot on measurement command
(FC, FD, RC, RD, SW, RL, MN, MX)
Figure 19
SRQ Mask Bits
Binary Value Bit Number Message
1 0 (LSB)
Error (IDDC, IDDCO, self-test fail)
2 1
Measurement overrange
4 2
Measurement underrange
8 3
Operation complete
4
Not Used
5
Not Used
6
Can’t mask
7 (MSB)
Not Used