DS7R Constant Current Research Stimulator

The Digitimer DS7R DC Research Stimulator provides pulse widths of 50 ?�s to 2 ms and outputs a DC current of up to 999 mA at 400 V. It can be used in human and animal research. It's NOT a medical device.

Overview
Specifications
References
Links

FEATURES

NOT a medical device; intended for human research use only.
Pulse lengths range from 50 µs to 2 ms.
From 400V, a steady current output of up to 999mA is possible.
Front panel push button or flexible TTL compatible trigger alternatives are available.
During stimulation, a toggle switch allows the stimulator to run in either +ve, -ve, or alternating polarity.

The DS7R offers up to 999mA constant current, high voltage pulses of brief duration for trans-cutaneous stimulation throughout examination of the electrical activity of nerve and muscle tissue, making it suitable as a general-purpose electrical nerve or muscle stimulator for peripheral stimulation in human research studies. The DS7R is specifically advised for use in human research applications where stimulation of vast muscle groups or deep nerve/nerve roots is possible because to its high voltage, high current, and adjustable pulse duration characteristics.

High Current & Flexible Pulse Duration Options

Based on the DS7AH, a device that has received medical approval, the DS7R Constant Current Research Stimulator is nearly identical. The output current is continually changing between two ranges of 0 to 99.9 mA and 0 to 999 mA, although it varies depending on the pulse durations that are available. The DS7AH permits pulses to last up to 200 µs, whereas the DS7R allows pulses to last up to 2 ms*. The DS7R is NOT medically certified and is only sold for use in human or animal research applications since this higher flexibility is only needed in those settings.

Safe for Human Research Use

The maximum pulse energy the DS7R can deliver has somewhat increased due to the relaxation of the pulse duration constraints. While this exceeds the international standard's (EN60601-2-40) 50mJ restriction for evoked potential stimulators, it is still significantly below the 300mJ limit for electrical stimulators used for therapeutic purposes in humans (EN60601-2-10).

The DS7R has an alternating polarity mode, similar to the DS7A and DS7AH, to prevent polarization of the stimulation site and potentially detrimental electrolytic effects of prolonged stimulation.

An external device, such as Digitimer's DG2A Train/Delay Generator, can trigger the DS7R. Please take a look at new DS8R Biphasic High Voltage Constant Current Stimulator for human research applications needing more flexibility in stimulus parameters and/or external control. Please see DS7A/AH High Voltage Constant Current Stimulators, the DS5 Bipolar Stimulator, or D185 MultiPulse Transcranial Cortical Stimulator for applications that call for a medically approved stimulator.

* The set current amplitude, stimulation frequency, and load impedance/available compliance voltage all affect the actual attainable current.

Specifications

Stimulus Output

CURRENT selected by 10 turn dial and x1/x10 switch.

Dial reading 00.0 to 99.9 giving 0 to 100 mA (99.9 mA) for x1 setting and 0 to 1000 mA (999 mA) for x10 setting.

PULSE DURATION 50, 100, 200, 500, 1000, 2000 microseconds (µs)

PULSE POLARITY Three position toggle switch selects Normal/Reverse/Alternating.

COMPLIANCE Continuously variable from 100V to 400V.

ON/OFF On is up. Off disables output and open circuits terminals.

CONNECTIONS 4 mm shrouded sockets (red and black) on 3/4" centres. Red socket goes positive with reference to

black socket.

Trigger

The Maximum trigger rate is 1,000 pps (1 kHz).

INPUT Electrical via Rear Panel BNC socket:

Triggers: Logic signal (+3 to 15V) +ve edge, TTL compatible (-ve edge by factory change). Minimum Pulse Duration is 5

microseconds.

Front panel: Push button.

Rear panel: 3.5mm mono jack socket for contact closure foot switch (contact closure).

OUTPUT Rear panel BNC, positive TTL pulse, 1 ms (950 ±50µs) wide (can be factory set for a negative pulse).

Indicators

TRIGGER LED - Amber, flashes for each trigger received.

POLARITY LED – Green, two LEDs indicate the polarity of the next output pulse.

TOO-FAST LED – Amber, Lit when trigger frequency exceeds 100Hz in Alternating Polarity Mode. Results in stimulus

output being disabled and FAULT condition (see below).

OUT OF COMPLIANCE LED - Amber, lit when selected current not delivered.

FAULT LED - Amber, illuminated on (i) sensed over-current internally (ii) over-current to the subject or (iii) Trigger

frequency “Too-fast” in alternating polarity mode. The unit is latched in this condition until reset by the Output On/Off

switch being placed in the OFF position.

POWER ON LED - Green, illuminated for power on

Dimensions

Size: 255 x 100 x 225 mm (d x h x w).

270 x 110 x 225 mm (d x h x w) - over controls and feet.

Weight: 2.1 kg (approx.).

Other

Power: 100 - 120V or 200 - 240V @ 47-63 Hz. Rating: <30 VA

Case Material UL94 V-0 Flame Retardant. Case Screw: 2.5mm Hex/Allen key compatible

ACCESSORIES

Supplied

Mains (Power) lead
Operator’s Manual

Reductions in motoneuron excitability during sustained isometric contractions are dependent on stimulus and contraction intensity.
Brownstein, C. G., Espeit, L., Royer, N., & ??�
(2021). Journal of Neurophysiology.
Reliability and agreement of a dynamic quadriceps incremental test for the assessment of neuromuscular function.
Varesco, G., Royer, N., Singh, B., Parent, A., F?�asson, L., Lapole, T., ??� Rozand, V.
(2021). Journal of Electromyography and Kinesiology, 56.
Influence of voluntary contraction level, test stimulus intensity and normalization procedures on the evaluation of short-interval intracortical inhibition.
Neige, C., Grospr??tre, S., Martin, A., & Lebon, F.
(2020). Brain Sciences, 10(7), 1??�16.

You can also visit site of the manufacturer.