Multichannel Systems USB-ME64-128-256-Systems Manual - Manual (Page 21)

Troubleshooting
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5.3.5 Rear Panel
5.3.6 Digital In / Out
A Digital IN / OUT for 16 digital in- and output bits is available (68-pin MCS standard connector).
The Digital IN / OUT connection accepts or generates standard TTL signals. TTL stands for
Transistor-Transistor Logic. A TTL pulse is defined as a digital signal for communication between
two devices. A voltage between 0 V and 0.8 V is considered as a logical state of 0 (LOW),
and a voltage between 2 V and 5 V means 1 (HIGH).
The Digital OUT allows generating a digital signal with up to 16 bits and read it out, for example,
by using a Signal Divider SD16 from MCS. You can utilize this digital signal to control and
synchronize other devices with the USB-ME256. Bit 0 of the Digital OUT is separated and
available as Lemo connector DIG OUT D0. So if you need only one bit of the digital signal,
you don’t need the additional signal divider SD16. Please read chapter "Pin Layout"
(Digital IN / OUT Connector) in the Appendix for more information.
The Digital IN can be used to record additional information from external devices as a 16-bit
encoded number. The Digital IN is most often used to trigger recordings with a TTL signal from
a stimulator. Therefore, the bits 0, 1, 2 and 3 of the Digital IN are accessible as the Lemo
connectors on the front panel as Digital Trigger Inputs 0 to 3.
The 16 digital input channels are represented as the Digital Data stream, that is, a stream of 16-bit
values, each bit (0 to15) representing one digital input. Standard TTL signals are accepted as input
signals on the digital inputs. Unused input bits, which have an undefined state, should be masked
in the Trigger Detector of MC_Rack.
Warning: A voltage that is higher than +5 Volts or lower than 0 Volts, that is, a negative
voltage, applied to the digital input would destroy the electronics. Make sure that you apply
only TTL pulses (0 to 5 V) to the digital inputs.
5.3.7 Digital Output D0
The Bit 0 of the Digital OUT is also accessible independently from the 68-pin digital IN / OUT
connector. The digital output channel D0 is generally used for synchronizing the USB-ME-System
with a stimulus generator, or with another data acquisition system, for example, an imaging
or a patch clamp system. The DIG OUT D0 generates standard TTL pulses.
5.3.8 Synchronization Out- and Input
If you want to use several USB-ME-Systems in parallel, the SYNC OUT and SYNC IN can be used
to synchronize the individual devices. The SYNC OUT of the first device must be connected to the
SYNC IN of the second, and so on. The cable for connection must have Lemo plugs on both heads.