Terminal board FAQ

common problem

1. Whether it is terminal block or relay, there are a large number of line contacts, the wiring process is complex, the duration is long, and the failure rate is high.

2. Different signal forms of different control instruments lead to different wiring methods. For example, the power line of the transformer and transmission instrument that needs distribution should be introduced from the distribution device, and the loop power supply transmitter is directly connected to the input side. Some are voltage signals or current signals, so it is difficult to find out the direction of the line without the drawing.

3. At present, the function of branching device and relay module used in DCS and PLC modules on the market is generally simple, and a large number of lead wires are needed, as shown in Fig. 3 and Fig. 4. In order to solve the uncertainty of contact type (normally open and normally closed), the module with dry contact output generally leads out the two contact points at the same time, occupying precious cabinet space. The analog signals are all introduced into the template in the form of wire dividers, whose function is only wire splitting.

4. At present, DCS / PLC and other automation systems use a large number of loop power supply forms, and there is no external power distribution device for the transformation and transmission instrument, so the problem of meter stop and meter removal is difficult to solve. In daily maintenance, the method of wire removal is generally used to cut off the power supply, which is not convenient, but also easy to contact other live connection points or misconnected during recovery.

5. In the process of maintenance, the detection of current signal must adopt the method of disconnection string ammeter, which interrupts the normal measurement process. If the circuit is in the automatic state, it is very easy to cause misoperation and production accident.

6. The common screw type terminal is easy to be affected by the personal habits of the installation personnel, which does not compress, resulting in poor contact.

7. Many devices are public power supply insurance, which is easy to cause multiple circuit power failure due to individual fault. When a single circuit is protected, the number of contacts is also increased by using insurance terminals.