1.2.4.1.1 Observe each display menu and alarming of DEH.
1.2.4.1.2 Print the fault diagnosis records. Check the abnormal conditions in the printed records.
1.2.4.1.3 Check the indicator of DEH cabinet, module, power, controller, operating station and engineer station. Take notes.
1.2.4.1.4 Back up the DEH configuration software. Record all of the set parameters.
1.2.4.2 Maintenance after system has been shut down
1.2.4.2.1 Visual inspections should meet the following requirements:
1) The appearance should be complete and in good condition. The directions of switches should be clearly marked. Name plate and signboard should be complete and correct, and the figures are clear.
2) The operation in the journey scope of control devices should be free, even and no blockage.
3) The position transmitter should be installed correctly and fixed firmly.
Fastenings should have no looseness. Movable parts should be free and reliable.
4) The wire connection should be correct, firm and no looseness. The connection between plug and plug socket should be reliable.
1.2.4.2.2 The maintenance, tests and management for the hardware and software of DEH control system should be carried out according to Chapter 4 and Chapter 5
1.2.4.2.3 Maintenance and calibration of measuring and process control instruments should be carried out according to Chapter 5 and Chapter 5.
1.2.4.2.4 The maintenance and quality requirements of control circuit and measuring pipe should be carried out according to Chapter 5
1.2.4.2.5 The performance inspections for power parts: step by step test the output voltage after energized. Each testing data should meet the requirements of the manufacturer manual. The power switches, indicators of all the modules should work normally.
1.2.4.2.6 Inspection and tests for the interfaces of DEH system and outside system. The communicating interfaces between DEH system and outside system should be correct and valid. They can share the information. The real-time characteristic of data transmission should meet the design requirements. Inspections and tests include:
1) Inspections of DEH system and bypass interface: step by step inspect the locking logic deactivated and activated by the bypass. It should meet the design requirements.
2) Inspections of DEH system and coordination control system interface: by the method of forced signal, check hard connection exchange signal and communication exchange signal between DEH and coordination system should be correct.
3) Inspections of DEH system and MIS system interface: check to ensure that the data transmitted from DEH to MIS should be correct. The real-time characteristic should meet the requirements.
1.2.4.2.7 Inspections of DEH system monitoring, operation, alarming, print and emergency SOE functions: check these functions to ensure they meet the requirements according to Chapter 4.
1.2.4.3 Requirements for Outside Signal Connection
I/A Series system installation and outside signals connections should be treated meticulously. They should be rationally designed and arranged. Requirements for cable installation: if there is cable chute, cabling slot and pipes, when install and
layout wires, the atmosphere conditions and electrical noise conditions should be considered. There are specific requirements for cables when considering the atmosphere conditions, such as temperature, moisture and corrosion during installation.
1.2.4.3.1 Modulating Signal Cable
The cable should adopt double twisted wire screen cable. All of the screen layer should electrically insulate with other screen layer. Make the screen layer grounding in the cabinet. The public bus bar in the cabinet is suitable for the onsite signal screen layer grounding after this connection.
1.2.4.3.2 Digital Signal Connection
Don not install the DC or AC onsite contact points in one cable. If the cable only has DC signals, the cable can choose not only twist pair total shielded wire cable, but also the cable only with total screen wire.
1.2.4.3.3 Input Signals of Thermocouple
The thermocouple input signal cable requires the special cable or the conducting line metal in the extending cable should be the same or similar with the thermocouple. This can reduce the potential difference produced during the connection of different metals. During the thermocouple signal is being transmitted, there can not be breakpoints, switches and connection points on the conducting line. All of the thermocouple signals should be shielded. Screen layers should be insulated.
1.2.4.3.4 Input Signals of Thermal resistance
The resistance of each conducting line connected with thermal resistance should be the same. The cable resistance values from the site to the cabinet should meet the limit of input template.
1.2.4.4 Inspection and commissioning
Before the device on-site activation, inspection on the following parts needs to be conducted:
1.2.4.4.1 Inspection of wiring
The wiring of this device has four modes:
1.2.4.4.1.1 The wirings between cabinets or internal wirings of the cabinets should be checked one by one according to manufacturer internal wiring diagram and tighten the loose terminals.
1.2.4.4.1.2 Inspection of cables: all the cables should be complete without damage, the two ends of signal wires inside the cable should be conducted, the insulations between the wires and between the wire and the cable screen layer should be adequate. If not, replace the cable. Check if all the empty residual cores and the screen layers of all the cables are grounded in the control panel according to the requirements and if the grounding is adequate. The empty residual core and the other end of the screen layer should be insulated with the ground.
1.2.4.4.1.3 Check if the wiring of each cable is correct.
1.2.4.4.1.4 Check if the wirings of all the external signals are correct according to the cabinet wiring terminal diagram.
1.2.4.4.1.5 Check if all the welding points of welded wiring inside the cabinet are reliable and check if there is any loose welding.
1.2.4.4.2 Inspection of the transmitter and the external signals
The control and monitoring parameters of the I/A Series control system are sent to the device after being detected by the transmitter, and the operation of the transmitter can directly influence the reliability of the system operation. Therefore, it is required to inspect the calibrated transmitter strictly according to the measurement range on the signal lists before activation.
All the external inspections described here mainly means the inspection if the onsite binary signal state consistent with the actual phenomenon. Click the button which represent the actual onsite condition and simulate certain state to verify the I/O binary.
1.2.4.4.3 Inspection of power supply and grounding wire
Before energization of I/A Series device, thoroughly inspect the installation and wiring of power supply and the grounding wire.
Following are the required equipment:
Multimeter: it is used to measuring the voltage and current;
Grounding resistance measurement tester: it is used to measuring the grounding pole resistance to ground;
Connection tester: it is used to indicating is the connection is correct;
Power supply monitor: it is used to recording the AC/DC voltage, current, temperature, humidity, radio wave frequency and the close/open state of the node.
1.2.4.4.3.1 Inspection of the grounding pole
The impedance of the grounding pole should be tested before the device has been energized or once a year. There are lots of testing methods to test the impedance of grounding pole. The grounding resistance tester is used to test the impedance, and the impedance of the grounding resistance should be less than 5Ω. If not, check the grounding wiring and the connection between the grounding pole and the power grid.
1.2.4.4.3.2 Measurement of electric grade
Power supply measurement includes: current, voltage and impedance testing;
Current test: use ammeter to measure and record the related current valid value;
Voltage test: use the multimeter to measure the AC magnitude of voltage from the power input end L－N、L－G、N－G part.
Impedance test: measure the input impedance of equipment connected with grounding wire or the zero line, and the smaller the impedance, the safer would be to the equipment and personnel.
1.2.4.4.3.3 Screen layer verification
The screen layer verification can be carried out in the cabinet. If the device is not energized, disassemble the DC grounding lead to carry out the following three tests:
Measure the resistance value between the cabinet and the insulation common grounding connection and the value should be less than 1Ω. If it is more than 1Ω, check the related connection and the system connection.
Measure the impedance between the cabinet support and the DC grounding
busbar and the value should be more than 1 megaohm;
If the measurement of the second step is less than 1 megohm, disconnect the common grounding wires of the other cabinets and the measuring cabinet. Then measure it again until find out the errors.
The possible reasons for the above problems may due to the short-circuit connection between the screen layer and the grounding, or the installation is inadequate or the connection is damaged. It also may be due to the different reference position of the input and output signals which are connected with the I/A Series system.
It is better to carry out the screen layer verification before the device has been energizated or during shutdown maintenance. During calibration, cut off the power supply of the device and it is not allowed to carry out these inspections when the devices controls the unit.
1.2.4.5 System function inspection
Before the activation of the I/A Series device, carry out the energization test via DEH simulation program to check if the I/A Series device hardware and software have any fault and if the system function can be normally operated, and this is one of the most effective measures to ensure the normal activation of the device.
Servo plate and the corresponding valve LVDT should meet certain linear relation so that the control system can normally control the CV and ICV valves. Calibrate the valves under the following conditions:
Before unit startup;
After the replacement of servo plate and the LVDT;
After normal maintenance;
Valve LVDT has been disassembled.
1.2.5 DEH System Function Test