Yes, all Sealevel relay racks allow an external power source to be connected to the V+ and Ground terminals. However, you need to take steps…
Do I need to add pull-up or pull-down resistors to my Sealevel inputs?
No. Sealevel optically isolated and dry contact inputs are current-mode inputs, which do not require external pull-up (or pull-down) resistors to be added for…
Can I guarantee that my Sealevel Digital I/O TTL adapter outputs always power on at zero volts?
Yes, many of our TTL products can be modified to always power on with an off-state of zero volts (TTL “low”). All of our standard…
Are Sealevel optically-isolated inputs active high or active low?
It depends on how the input is wired to your application. An input is triggered when the input terminal and local common terminal of…
What is the difference between SeaLINK 820x and 820xFX digital I/O adapters?
Sealevel strives to minimize the impact of component obsolescence to our customers. When a component is discontinued by a vendor, Sealevels goal is to…
Why are solid-state relay modules different colors?
The color is used to identify the type. The open-standard color scheme was developed by Opto 22 in 1978 to help identify the four basic…
What wire colors are used for RS-485 on a SeaI/O module?
We assume that you want to use a standard (CAT5/6 EIA/TIA-568B) Ethernet patch cable to connect to the RJ45 pass-through connector on the side…
Why does my Sealevel Digital I/O TTL adapter have 5 volts present after system power on?
TTL I/O devices are commonly used to control solid-state relay modules that interface a variety of input and output devices. An important consideration in these…
What is the default power up condition of a Sealevel TTL Digital I/O product?
All Sealevel TTL Digital I/O products are configured to power up in input mode by default. This ensures that no outputs are inadvertently activated.…