Tacho Set A Failure 及 典型案例分析

一、注意/Note：

如Tacho Set A Failure和 Tacho Set B Failure 同时出现在一个CCU单元，且需要保持30分钟以上运行时，则需使用汽缸油备用电缆。 具体接线方式如下：

Backup lubrication cables must be fitted if both Tacho set A and Tacho set B failure occurred on one CCU, and continued operation is needed for more than 30 minutes. The wiring details as belows: 

用备用电缆将受影响的气缸润滑器连接到ECU A或B的通道J52。（适用于ME-C机型）

Connect affected cylinder lubricator to channel J52 of ECU A or B with the temporary back-up cable.（Suitable for ME-C type Engine）

或者 / Or

拔出故障CCU上的J49插头，然后用临时备用电缆连接非故障CCU上的备用通道J51。(适用于ME-B机型)

Disconnect connector J49 on defect CCU, then connect to the back-up channel J51 on non-defect CCU with the temporary back-up cable.（suitable for ME-B Type engine）

二、 可能原因及故障排除/ Possible Reason and Trouble Shooting

(一）MSA 信号故障/ MSA signal failure：（High failure rate）

1.  MSA探头故障(高故障率)或者MSA探头至TSA-A放大器的电缆故障。假如MSA信号故障，所有的CCU和ECU将触发Tacho Set A failure警报。

MSA Sensor failure（High failure rate）or cabling failure between MSA sensor and TSA-A amplifier. All of the CCU and ECU units will activating the alarm of Tacho Set A failure once the MSA signal failure. 

下图为MSA信号故障的功能测试界面。

The following is the function test interface of MSA signal failure.

2. 通过临时接线来快速判断是否MSA信号故障（无MSA探头备件，亦可使用此方法消除报警）。

Quickly determine whether the MSA signal is faulty by temporary wiring (This method can also be used to eliminate alarms without  MSA sensor spares).

临时接线步骤如下/ Temporary wiring procedure as below: 

(1）脱开TSA-A放大器的J4插头 / Pull out the cable plug J4 from TSA-A amplifier.

(2)  连接编码器A的线芯E和F到J4电缆插座上的B和C。(E和F通常闲置在TSA-A盒中，不连接任何端子插座)

Connect E & F (from Encoder A) to B & C on J4 cable socket. (E & F are normally idle in TSA-A box and not connected to any terminal socket)

(3)  如果临时接线后，Tacho set A Failure 警报消除，则可以确定MSA信号有问题，需要检查接线情况或者换新MSA探头。

If Tacho set A failure alarms are eliminated after the temporary cabling, then we can determine the MSA signal has problem and need to  check cabling condition or renew the MSA sensor .

(二) 硬件故障：角度编码器A探头故障、或TSA-A 放大器故障、或MPC、MPC-10 （CCU\ ECU）故障。（故障率不高）

Angle Encoder A sensor failure, or TSA-A amplifier board failure, or MPC\MPC-10 failure (CCU\ ECU) .（Low failure rate）

1. 如角度编码器A探头故障 或 TSA-A放大器故障，通常所有CCU和ECU都会触发Tacho set A Failure。而如果是MPC、MPC-10故障，则Tacho Set A failure只会单独出现在某个MPC、MPC-10单元。

If the Angle encoder A sensor or the TSA-A amplifier fails, usually all CCU and ECUs will trigger A Tacho set A Failure. If it is a MPC or MPC-10 fault, Tacho Set A failure occurs only on one MPC unit.

2. 假如只有一个CCU或者ECU出现Tacho Set A failure警报，则先检查故障CCU或ECU的J40~J43通道的接线是否有松动或电缆破皮接地等情况。如接线OK，则需换新CCU或者ECU。

If only one CCU or ECU reports Tacho set A failure, check the cabling conditions of J40-J43 on failure CCU or ECU, such as wires loosing connected or grounded and so on. If cabling conditions are OK, then replace the CCU or ECU unit. 

3. 假如所有的CCU和ECU都出现了Tacho set A failure。首先确认Encoder A探头的机械安装及机械定时是否异常。其次，电气方面检查，比如Encoder A探头到TSA-A放大器箱和ECS控制箱的所有接线情况(包括电源电压)。

If all CCUs and ECUs report Tacho Set A failure. Firstly  checking whether the mechnical installation and basic mechnical timing conditions of the Encoder A are abnormal. Sencondly, checking the Electrical conditions, such as cabling conditions from Encoder A probe to TSA-A amplifier and ECS cabinets（including Power voltage）. 

(1) 机械安装方面：主要检查探头螺栓及固定支架等零件是否松动破损。 

About the mechnical installation: mainly check whether the fixing bolts and brackets of the Encoder A sensor are loosing or damaged. 

   

(2) 机械定时方面：盘正车至TSA-A放大器的LED灯刚亮，检查此时的飞轮角度是否为0±0.5度（尽可能无限接近0度）。如定时角度偏差大，则需按照本公众号文章《ME电喷主机角度编码器之自由端布置1》中的调整步骤进行重新调整。 

Regarding the basic mechnical timing: comfirm by ahead turnning the engine until the LED light of TSA-A amplifier is just light up, then checking the crank angle which should be 0±0.5 degrees (as close to 0 degree as possible). If the timing angle deviation is too large, It needs to be re-adjusted according to the adjustment steps in this public number article 'ME电喷主机角度编码器之自由端布置1'.

（3）电气情况方面： 主要检查是否有接线松动？线芯是否破损接地？电缆屏蔽是否良好接地？电源电压是否正常等？

Electrical conditions: mainly check whether the wiring is loose？The wire core is damaged and grounded？The cable shielding is well grounded？The power voltage is normal？

更多接线方面的规范要求及常见电缆故障，请见本公众号文章《Wiring specifications and precautions for ME Engine.》

For more Wiring specifications and common cable faults, please see the article 'Wiring specifications and precautions for ME Engine'

（4）通过盘车查看CCU的J40~J43通道的变化来快速定位故障信号点。通常情况下，J40~J43通道的变化规律如下：

check the change status of the J40~J43 Channels in CCU can help us to quickly locate the fault signal. Normally, the change rules of J40~J43 are as follows:

J40 J41	盘车一圈，True/False 变化两次。 Ture/False changed twice per revolution.
J42 J43	盘车一圈，True/False一直交替变化。  Ture/False changed multiple times per revolution (360).

(5) 如角度编码器系统为飞轮端布置，则需按照本公众号文章《MAN电喷主机Tacho系统之飞轮端布置》中的“零部件认识与安装调整”内容进行检查与评估。

三、功能测试\ Function Test

如下情况下，建议在MOP上进行一次功能测试，并确保测试顺利通过。

In the following cases, it is recommended to perform a functional test on MOP, and ensure that the test passes successful. 

（一）角度编码器A探头换新或重新调整机械定时。

Angle Tacho A sensor replaced or the basic mechnical timing re-adjusted. 

（二）MSA探头换新或者重新调整机械定时。

MSA sensor replaced or the basic mechnical timing re-adjusted. 

（三）TSA放大器换新或者内部接线重新布置。

TSA amplifier replaced or internal wires rearranged. 

功能测试更多详情，请见本公众号文章《ME电喷主机角度编码器之自由端布置1》中的“角度编码器的功能测”内容。

For more function test details, please sea the 'Function test for Tacho' in the article <ME电喷主机角度编码器之自由端布置1>

四、案例分享/ Typical case sharing

(一) 故障描述/ Failure Description 

1. 某轮配备主机机型5S50ME-B9.3，自由端配置的角度编码器系统。主机运行时,所有CCU同时触发警报：Tacho set A failure, Tacho Alignment Err 和Delta Tacho B too big 。如下图所示：

One vessel equiped the Mian Engine type of 5S50ME-B9.3, and the tacho system is amounted at the Fore side. The alarms of Tacho set A failure \ Tacho Alignment Err and Delta Tacho B too big were activated on all CCU units when Main Engine was running. More details as follows：

2. 功能测试结果不稳定，有时能通过，有时不能。

The results of function tests are erratic, sometimes passed and sometimes not passed.