D188 & D189 Remote Electrode Selectors

D188 & D189 Remote Electrode Selectors

£2,200.00 exc. VAT

Manufacturer's Net List Price

FEATURES

  • Rapid switching (<1ms) between up to eight pairs of electrodes.
  • D188 and NEW D189 are offered for different voltage sources.
  • Digital switching or virtual front panel software control.
  • No visual or audible cues of switching (optional LED indicators).
  • Designed for safety in human research studies.

Description

DESCRIPTION

The D188 Remote Electrode Selector and the new D189 Low Voltage Electrode Selector allow you to direct an electrical stimulus of up to 1A from a single stimulator to one of up to eight pairs of electrodes.  The D188 is intended for applications where the stimulator voltage might exceed 100V (e.g. DS5, DS7A, DSAH, DS7R or DS8R), while the D189 is intended for use with stimulators that do not generate more than 100V (e.g. DS2A, DS3, DS4).

Both the D188 and D189 are supplied with “virtual front panel” software compatible with WindowsTM 7 and higher, which permits manual switching between stimulation sites via a key-press or mouse click.  However, the remote electrode selectors were predominantly designed for situations where stimulation delivery needs to be rapidly switched between sites under remote, digital control.  With switching times of 1ms, the D188 and D189 Electrode Selectors can be used for demanding stimulation applications involving multi-location stimulation in studies of pain, cognitive behaviour or sensory perception.  An example of a typical stimulation system incorporating the D188 is given in the diagram below.

D188 Electrode Switcher Digitimer

Multiple control methods
Precisely timed remote control is possible through the use of TTL compatible digital lines from your data acquisition system. One to one control requires eight digital inputs, however, the D188/D189 Remote Electrode Selectors can also operate in a multiplexed mode where only four digital inputs are required.  Alternatively, a USB connection to the host computer allows software control of the D188/D189 via a DLL-based API, which can be accessed using your preferred software (C, C++, Visual Basic, C# etc). The D188 and D189 are recognized and controllable as serial devices within LINUX operating systems, although our virtual front panel software is not LINUX compatible.

Designed for research applications

The D188 and D189 are silent in operation and the software control panel allows the operator to toggle the LED indicator lights on and off. As a result, the subject of stimulation is not provided with any audible or visual cues of stimulus delivery. The D188 and D189 Electrode Selectors are not medical devices and use is restricted to research applications, however, they have been designed to meet certain aspects of IEC 60601-1 relating to safety in human use.

The D188 and D189 are not supplied with any stimulator input or electrode connection cables, however, it is possible to purchase additional plugs and cables to suit your requirements.  These allow direct connection to our complete range of isolated stimulators. We also offer output extension cables in order to increase the distance between the stimulating electrode and the D188/D189 output sockets.

Multiple Stimulator Connection Options

Recommended Connection via D185-HB4 Output Adaptor Cable
For direct connection to a D185-HB4 Output Extension Cable, the D188-09 (200cm) or D188-10 (50cm) 1.5mm cables can be connected between the D188/D189 Electrode Selector and the D185-HB4.

Read more

DOWNLOADS

D188/D189 Remote Electrode Selector
Product Datasheet

D188/D189 Remote Electrode Selector
Accessory Cable Datasheet

D188/D189 Remote Electrode Selector
Digital Control Schematic

D188 Remote Electrode Selector
Application Note

Use of the DS5 Bipolar Constant Current Stimulator
with the D188 Remote Electrode Selector.

D188/D189 Remote Electrode Selector
Operator’s Manual

D188/D189 Control Software v3
for Windows x86/x64

PUBLICATIONS

DOWNLOAD BROCHURE

Digitimer-Life-Science-Brochure-1

ACCESSORIES

Supplied

  • Remote Electrode Selector.
  • Power Supply with adaptor plates for European, North American and UK plugs.
  • USB Cable, 2m long.
  • Digital Communication Cable (15-way “D” to bare wires), 1m long (D188-08).
  • Virtual Front Panel Software, supplied on USB stick.
  • Operator’s Manual

Recommended

FAQs

If I wanted to stimulate at more than 8 different sites, is is possible to use more than one D188?
In order to use more than one D188 and a single stimulator, it will be necessary for the user to connect the stimulus source, in parallel, to the COM inputs of each D188. In this case, our D185-HB1 output adaptor cable would be a suitable alternative to our D185-HB4. Alternatively, the stimulus source can be connected to a single D188 and one output channel of that unit used to pass the stimulus to a second D188. In this way, multiple D188’s can be “daisy chained” to one stimulator.
For our surface stim paradigm, the longest pulse we use is 500 usec (with a 2500 usec recovery phase). So if we assume a 3000 usec (3 ms) total pulse time, at 100 Hz we could conceivably do 3 channels with this setup, correct? Or, if we go down to 2 ms total pulse duration, including recovery, we could easily do 4 channels at 100 Hz. At lower frequency, we could then go to more channels, i.e., at 50 Hz, we could do 8 channels with 2 ms total pulse duration. Is my thinking correct here?
If we allow 3ms for each stimulation pulse and a 1ms gap between them to allow the D188 to switch, then this give a total time of 12ms. This should mean each site can be stimulated ~83Hz. With the pulse duration reduced to 2ms and retaining the 1ms interval, this increases to 111Hz. It is important that as well as the total time spent stimulating, they also allow for the D188 relays to fully switch channels. The 1ms may be a little conservative, but they could experiment with timings to get an idea of how fast they can do this with their particular control method.
Do you have any hardware recommendations in respect of digital control solutions?
The D188 accepts standard TTL logic pulses which can be provided by an array of commercially available data acquistion/control hardware.  Products from Cambridge Electronic Design, National Instruments, Labjack and many others have all been used to control the D188 for a variety of applications including psychological testing and pain scoring.
I see that the D188 comes with Windows compatible control software, are you able to supply drivers or software for alternative operating systems like Linux or iOS?
Digitimer only develops for the Windows environment, so unless you are able to run a Windows emulation, we would suggest that you configure the settings of the D188 using a Windows PC. As the settings are persistent, the D188 can then be controlled with digital inputs from a data acquisition interface rather than via the USB connection.
I want to stimulate two locations in quick succession. How quickly can channels be switched using TTL/digital control?
It is important to appreciate that the electrode switching process is not instantaneous. It takes several hundred microseconds for the D188 to switch channels in response to a change in the TTL state of the digital inputs. We recommend that stimulus delivery and digital switching protocols are devised which allow for at least a 1ms pause in stimulation following a digital input state change.  If this pause is not adhered to, stimulation may occur in multiple channels during the 1ms transition period.

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    Additional information

    Option

    D188 Remote Electrode Selector (for >100V), D189 Low Voltage Electrode Selector (for <100V)