Operator's Manual
DS7A - Constant Current Stimulator
stimulation pathway is too high for the stimulator to overcome.
12. * A FAULT is indicated by an amber LED. When lit this indicates that the unit has detected a
possible internal fault and should not be used. This LED will also illuminate if the DS7A is triggered
“too fast” (i.e. <10ms repetition interval) in Alternating Polarity Mode. NB: As a test, this indicator
will illuminate at power-on for a few seconds. If the Output Enable Switch (9) is ON, it
must
be
switched into the OFF position to reset the circuitry before use of the unit.
13. Green LED, lit to confirm that the next output pulse will be Normal polarity.
14. Three position Polarity Control toggle switch. Left for Normal, Centre for Alternating and Right for
Reverse.
15. Green LED, lit to confirm that the next output pulse will be Reverse polarity.
16. Amber LED, lit to warn the operator that the trigger frequency exceeds 100Hz (i.e <10ms repetition
interval. This only applies when the stimulator is set to alternating polarity mode.
Notes on Front Panel Controls
1. With the Output Enable switch [9] in the “ON” (upward) position:
i.
The FAULT lamp [12] will be on at POWER-ON;
ii. The FAULT lamp [12] will come on if a Fault is detected;
iii. The FAULT lamp [12] will NOT go off;
iv. The Output Enable switch [9] must be placed in the “OFF/reset” (downward) position until it
does go off;
2. With the Output Enable switch [9] in “OFF/reset” (downward) position:
i.
The FAULT lamp [12] will be on for ~5 seconds at POWER-ON;
ii. The FAULT lamp [12] will be on for ~1 second if a transient FAULT is detected;
iii. The FAULT lamp [12] will stay on if a PERMANENT fault is detected.
3. When the FAULT lamp [12] is on, no stimuli will be presented to the subject;
4. As a precaution against inadvertent triggering of stimuli to the subject, the Output Enable switch [9]
should be placed in the “OFF/reset” (downward) position when stimuli are not required.
It is a good habit to place the Output Enable switch [9] in the “OFF/reset” (downward) position
before Power-off, so that it is in the “OFF/reset” (downward) position at Power-on. The FAULT lamp
[12] will then automatically extinguish after about 5 seconds. (unless there is an internal fault
detected);
Digitimer Ltd.
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File Ref: N:\Docs\Company\Manuals\DS7A\Issue-14\DS7A-iss14.odt
Last Revised: February 1, 2017
