Fluke 45 user manual 3.Trigger Type

Operating the Meter Using the Computer Interface	5
Service Requests (IEEE-488 Only and Status Registers

A measurement is triggered while the input is greater than +3 V. A method for using DTR (pin 4) and an external switch to trigger a measurement is shown in Figure 5-2.

•Send the IEEE-488 GET interface message (IEEE-488 Operations).

Table 5-3. Trigger Type

Type

1

2

3

4

5

Trigger

Internal

External

External

External

External

Rear Trigger

Disabled

Disabled

Disabled

Enabled

Enabled

Settling Delay

—

Off

On

Off

On

Table 5-4. RS-232 and IEEE-488 Reading Transfer Rates

Readings per Second

RATE

Slow

Medium

Fast

Internal Trigger Operation

(Trigger 1)

2.5

4.5

4.5

Internal Trigger Operation

(Trigger 4)

1.5

2.4

3.8

DTR (PIN 4)

RX (PIN 2) TRIGGER TO ∝ P

aam20f.eps

Figure 5-2. External Trigger Using Receive Pin (RX) of RS-232 Interface

Service Requests (IEEE-488 Only and Status Registers

Service requests let a meter on the IEEE-488 bus get the attention of the host. Service requests are sent over the service request (SRQ) bus line.

Note

If the meter is in the remote state without front panel lockout (i.e., REMS), a service request can be sent from the front panel by pressing U.

If more than one instrument on the bus is capable of sending service requests, the host can determine which instrument made the request by taking a "serial poll." Each instrument on

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