Filter
Top Products
HYDRA
Service Manual
4-16
3. Verify that Hydra is still in the total measuring mode. If not, press the TOTAL
button. Reset the totalizer count shown on the display by pressing the SHIFT and
TOTAL(ZERO) buttons.
The Hydra display should now show a value of 0.
4. Connect the output of the signal generator to the
∑ and J terminals.
5. Program the signal generator to output a 1.5V rms sine signal at 10 Hz.
The Hydra display should now show the totalizing value incrementing at a 10 count
per second rate.
4-18. Dedicated Alarm Output Test
The Dedicated Alarm Output Test verifies that Alarm Outputs 0 through 3 are
functioning properly. Because this test is dependent on voltage readings the Accuracy
Verification Test for channel 0 and the Channel Integrity Test for channels 1 through 3
should be performed if voltage readings are suspect.
1. Switch OFF power to the instrument and disconnect all high voltage inputs.
2. Remove the eight-terminal Alarm Output connector from the rear of Hydra and all
external connections to it. Connect short wires (to be used as test leads) to the [J]
and 0 through 3 terminals. Leave the other ends of the wires unconnected at this
time. Reinstall the connector.
3. Remove the Input Module from the rear of Hydra. Open the Input Module and
jumper the H (high) terminal of channels 1, 2, and 3 together. Connect a test lead to
the H of channel 1. Also jumper the L (low) terminals of channel 1, 2, and 3
together. Connect a second test lead to the L of channel 1. Reinstall the Input
Module into Hydra. Refer to Figure 4-3.
4. Switch power ON.
5. Using a digital multimeter (DMM), verify that alarm outputs 0 through 3 are in the
OFF or HIGH state. Perform this test by connecting the low or common of the
multimeter to the ground test lead and the high of the multimeter to the alarm output.
Verify a voltage greater than +3.8V dc.
6. Connect a cable from the Output VA HI and LO connectors of the 5700A to the VΩ
and COM connectors on the front panel of Hydra. Then jumper the Hydra VΩ
terminal to the H (high) test lead of the Input Module and the COM terminal to the L
(low) test lead.
7. On Hydra, select the VDC function, 3V range, and assign a HI alarm limit of
+1.0000 for channels 0 through 3. Set up all other channels (4-20) to the OFF
function. Select a scan interval of 5 seconds.
8. Set the 5700A to output +0.9900 volts.
9. Press SCAN. Hydra should scan channels 0 through 3 every 5 seconds.
10. Using a digital multimeter, again verify that alarm outputs 0 through 3 are in the
OFF or HIGH state.
11. Set the 5700A to output +1.1000 volts. Verify that the alarm outputs 0 through 3 are
in the ON or LOW state (measure less than +0.8V dc).