Many of the terminal boards in the Mark VI use a 24-position pluggable barrier terminal block (179C9123BB). These terminal blocks have the following feat
• Made from a polyester resin material with 130°C (266 °F) rating
• Terminal rating is 300 V, 10 A, UL class C general industry, 0.375 in creepage, 0.250 in strike
• UL and CSA code approved
• Screws finished in zinc clear chromate and contacts in tin
• Each block screw is number labeled 1 through 24 or 25 through 48 in white
• Recommended screw tightening torque is 8 in lbs.
Terminal Board Disconnect Switch (TBSW)
The Mark VI control Terminal Board Disconnect Switch (TBSW) provides individual disconnect switches for each of the 48 customer I/O points on Mark VI control terminal.This facilitates such procedures as continuity checking, isolation for test, and others. Two TBSW assemblies are required for each terminal board, one numbered 1-24, the other numbered 25-48, (GE part numbers 336A4940CHG1 and 336A4940CHG2 respectively).
The TBSW fits and connects into the terminal boards' 24-point pluggable barrier terminal block receptacles.
The TBSW is designed for continuous 5 A rms current at 300 V rms and complies with EN61010-1 clearance specifications. The NEMA power/voltage class rating (A, E, F, G) for the TBSW is dependent on the terminal board the TBSW is mounted upon.
The following table lists the TBSW terminal board applications for the Mark VI control.An OK in the TBSW applications column indicates an approved application of the TBSW with regards to specifications for voltage and current. Those board points that require limiting the terminal board applications are indicated with a Note number.
Simplex DIN-Rail Mounted Terminal Board：
Speed control systems for small turbines require simplified system architecture. Simplex control is used to reduce cost and save space. Compact DIN-rail mounted terminal boards are available instead of the larger T-type terminal boards used on TMR systems.IONet is not used since the D-type terminal boards cable directly into the control chassis to interface with the I/O boards.
In the VME rack, a VCMI board provides two-way communication between the controller and the I/O processor boards. The controller Ethernet port is used to communicate with other system components, such as an operator interface or PLC. Additional PLC I/O can be tied into the system using the controller Genius port. A typical system is illustrated in the following figure. The system is powered by 24 V dc, and uses a low voltage version of the standard VME rack power supply
The board designations and functions along with the corresponding I/O processor boards are listed in the following table. In all cases, the signal conditioning on the DIN-type terminal boards is the same as on the T-type boards, and the I/O specifications described apply. However, the number of inputs and outputs, and the grounding provisions differ, and the boards do not support TMR. Permanently mounted high-density Euro-block terminal blocks are used to save space. The blocks have terminals accepting wire sizes up to one #12 wire, or two #14 wires. The typical wire size used is #18 AWG.