IS230STCIH2A

IS230STCIH2A is a Contact Input Terminal Module manufactured and designed by General Electric as part of the Mark VIe Series used in GE Distributed Control Systems. The STCI board is a compact contact input terminal board designed for DIN-rail or flat mounting. The STCI board accepts 24 contact inputs that are supplied with a nominal 24, 48, and 125 V DC excitation from an external source. The contact inputs have noise suppression to protect against surge and high-frequency noise. In the Mark VIe systems, the PDIA I/O pack works with the STCI. The I/O pack plugs into the D-type connector and communicates with the controller over Ethernet. Only simplex systems are supported.

INSTALLATION:

The STCI plus a plastic insulator mounts on a sheet metal carrier that then mounts on a DIN rail. Optionally the STCI plus insulator mounts on a sheet metal assembly that then bolts in a cabinet. The contact inputs are wired directly to the terminal block, typically using #18 AWG wires. Shields should be terminated on a separate bracket. Two types of Euro-block terminal blocks are available:

OPERATION:

The function and on-board signal conditioning are the same as those on TBCI, they are scaled for 24, 48, and 125 V dc excitation. The input excitation range is 16 to 32 V dc, 32 to 64 V dc, and 100 to 145 V dc respectively. The threshold voltage is 50% of the excitation voltage. The contact sensing circuits are shown in the figure. Contact input currents are resistance limited to 2.5 mA on the first 21 circuits, and 10 mA on circuits 22 through 24. The 24 V dc supply is currently limited to 0.5 A using polymer positive temperature coefficient fuses that can be reset. Filters reduce high-frequency noise and suppress surge on each input near the point of signal entry. The discrete input voltage signals go to the I/O processor which passes them through optical isolators, converts them to digital signals, and transfers them to the controller.