IS200STCIH6A is a Simplex Contact Input Terminal Board manufactured and designed by General Electric as part of the Mark VIe Series used in Distributed Control Systems. Compact contact input terminal boards for DIN-rail or flat installation are available, such as the Simplex Contact Input (STCI) terminal board. The STCI board can accept 24 contact inputs from external sources that are stimulation with nominal 24, 48, and 125 V dc. The noise suppression on the contact inputs guards against surges and high-frequency noise. With Mark VIe and Mark VIeS systems, the STCI is compatible.
Compatibility
The STCI and PAIC I/O packs are compatible. The I/O pack connects to the D-type connection and uses Ethernet to interact with the controller. There is just support for simplex systems.
IS200STCIH6A Installation
A sheet metal carrier that is mounted on a DIN rail carries the STCI along with a plastic insulator. The STCI plus insulator may instead install to a sheet metal assembly that is subsequently fastened within a cabinet. The terminal block is directly wired to the contact inputs, commonly using #18 AWG wires. Shields should end on a distinct bracket.
Operation
They are scaled for 24, 48, and 125 V dc excitation and have the same function and onboard signal conditioning as those on TBCI. There are three different input excitation ranges: 16 to 32 V dc, 32 to 64 V dc, and 100 to 145 V dc. 50% of the excitation voltage is the threshold voltage. The figure shows the touch sensing circuits. On the first 21 circuits, contact input currents are resistance limited to 2.5 mA, and on circuits 22 through 24, to 10 mA. Using resettable polymer positive temperature coefficient fuses, the 24 V dc supply is current limited to 0.5 A.
On each input close to the signal entrance point, filters decrease high-frequency noise and prevent surges. The I/O processor receives the discrete input voltage signals and converts them to digital signals before sending them to the controller after passing them through optical isolators.