2620A, 2625A
Users Manual
6-16
Digital Output Test
1. Ensure that communication parameters (i.e., transmission mode, baud rate, parity,
and echo mode) on the Hydra Series II and the host are properly configured to send
and receive serial data. Refer to Chapter 4.
2. Switch OFF power to the instrument and disconnect all high voltage inputs.
3. Remove the Digital I/O ten terminal connector from the rear of the instrument and
all external connections to it. Connect short wires (to be used as test leads) to the
ground (J) and 0 through 7 terminals. Leave the other wire ends unconnected at this
time. Reinstall the connector.
4. Switch power ON to both Hydra Series II and the host. Verify that Hydra Series II is
not scanning. If Hydra Series II is scanning, press SCAN to turn scanning off, then
cycle power off-on again.
5. Using a digital multimeter (DMM), verify that all digital outputs (0-7) are in the
OFF or HIGH state. This is done by connecting the low or common of the
multimeter to the ground test lead and the high of the multimeter to the digital output
and verifying a voltage greater than +3.8V dc.
6. Using either a terminal or a computer running a terminal emulation program, set up
Hydra Series II to turn Digital Outputs ON (LOW state). In sequence send the
following commands to Hydra Series II and measure that the correct Digital Output
line transitioned LOW measures less than +0.8V dc.
DO_LEVEL 0,0 <CR>
Assure output 0 measures a LOW state.
DO_LEVEL 1,0 <CR>
Assure output 1 measures a LOW state.
DO_LEVEL 2,0 <CR>
Assure output 2 measures a LOW state.
Repeat the command for all eight outputs.
7. Set up Hydra Series II to turn Digital Outputs OFF (HIGH state).
In sequence send the following commands to Hydra Series II and measure that the
correct Digital Output line transitioned HIGH measures greater than +3.8V dc.
DO_LEVEL 0,1 <CR>
Assure output 0 measures a HIGH state.
DO_LEVEL 1,1 <<CR>>
Assure output 1 measures a HIGH state.
Repeat the command for all eight outputs.
Digital Input Test
1. Perform the DIGITAL OUTPUT TEST steps 1 through 5.
2. Using either a terminal or a computer running a terminal emulation program, set up
Hydra Series II to read the Digital Input lines.
Send the following command to Hydra Series II:
DIO_LEVELS? <CR>