Eaton MTL F809F Plus DTM Operating Instructions



MTL F809F Plus DTM Operating Instructions

In the on-site maintenance of the Foundation Fieldbus system, the value of the MTL F809F Plus diagnostic module is not just to "look at a few voltage values", but to integrate the system power supply, segment noise, equipment signal amplitude, retransmission rate, and alarm limits into a set of DTM interfaces. Many on-site faults are manifested as "communication is sometimes good and sometimes bad", "occasional disconnection of a certain device", "DCS alarm but on-site equipment is normal". If only a multimeter and handheld device are used to troubleshoot point by point, the efficiency is very low. The function of F809F Plus DTM is to convert these hidden faults into comparable, exportable, and printable diagnostic data. If the on-site engineer can clarify the three-layer relationship between DTM upload/download logic, system TB, segment TB, and device TB, troubleshooting will be much faster.

DTM launch and data consistency

F809F Plus DTM runs in FDT framework or DCS asset management environment, and may not generate shortcuts in the start menu after installation. The device directory needs to be refreshed before it can be seen. DTM performs automatic upload when switching from offline to online, updating device and instance datasets while retaining the working dataset that the user is currently modifying. Manually uploading is different, as it synchronizes both the instance dataset and the working dataset to the data in the F809F device. If a download is in progress, both automatic and manual uploads will be ignored. The most common problem on site is that engineers change the alarm limit in DTM, but do not click "Apply" when they see the pencil symbol, and then download the old template from the DCS engineering station to overwrite the on-site values. Therefore, after modifying the limit value, it should be confirmed whether the status area displays "Device" or "Data set", whether the pencil symbol disappears, and if necessary, manually upload it before making a comparison.

The diagnostic interface is divided into two tabs: "Diagnosis" and "Configure/Set up". The former only displays measurement values and status icons, while the latter allows modification of low low, low, high, and high high alarm limits. There is only an upper limit to noise, because the lower the noise, the better. The navigation tree will propagate lower level faults upwards: device faults will be displayed as segment faults, and segment faults will be displayed as module faults. If a certain icon alarms but the segment parameter page displays normally, the device nodes under that segment should be expanded, as the problem often lies at the device layer. The monitoring section is marked with a check mark, while the unmonitored section is not marked with a check mark; The unscanned segment can remain in its final state, or it can be set to null using 'Set Non scanning Segment Values to null'.

System TB: Power, Temperature, and Latch Alarm

The TB system corresponds to the Fieldbus power carrier and the F809F Plus module itself. The diagnostic page displays the Power feed A/B voltage and module temperature. The default operating range of power supply A/B is usually 19.2V to 30V. The low low, low, high, and high limit values must be set in ascending order, with the high limit being at least 1V higher than the low limit and an alarm delay of about 0.5V. F809F internally rounds the input value to one decimal place, while DTM may not be rounded to the whole. Therefore, when inputting 23.34V, a pencil symbol may always be displayed. It is best to directly input a one decimal value such as 23.4V. The default high limit and high high limit for module temperature are 65 ℃. In practice, they should be adjusted based on the maximum operating temperature of the power module and the normal temperature inside the cabinet. They are usually set at the lower of the maximum allowable temperature of the power supply or the normal temperature plus 10 ℃.

The system TB is also responsible for monitoring segment selection, non scanning segment emptying, and alarm locking. Default monitoring of 8 segments; If only partial segments are used on site, unused segments should be scanned and left empty to avoid noise or voltage alarm interference in the empty segments. When troubleshooting a certain section, you can temporarily check only that section and restore all active sections after the problem is resolved. Alarm latch is used to capture intermittent alarms: once an alarm occurs, even if the problem disappears, the message remains until "Latching Alarm Acknowledge" is clicked. This is very useful for unmanned stations, but it will increase the workload of confirmation and needs to be set according to the maintenance system.

The wizard for system TB includes resetting the retransmission counter, deleting historical data, setting date and time, and optimizing power alarm limits. Reset retry counters "can reset all segments and devices, specified segments and their devices, only specified segments, or a specific device on a specified segment. Resetting the measurement processor can restore the fault state, but it will delete device and segment tag data. Before operation, it must be backed up and re downloaded. Alarm Limit Optimization only adjusts the low and high limits of the power supply, without changing the low and high limits; If the new value is not in order with the existing low/high/high limits, the wizard will reject or request a re-entry. If you want to set the high limit higher than the current high limit, you should manually change the high limit first.

Segment TB: Voltage, Noise, Signal Amplitude, and Number of Devices

Duan TB is the core of on-site troubleshooting. The default low limit for segment voltage is 18V and the high limit is 32V, which should be adjusted according to the actual fieldbus power data sheet. Check the power carrier output, distribution, and wiring for low voltage alarm; High voltage warning for power module and load.

Noise is divided into three levels: low frequency from 25Hz to 3.8kHz, in band from 5kHz to 55kHz, and high frequency from 90kHz to 350kHz. Each level is further divided into average and peak values. The default pre alarm/warning limit for average noise is low-frequency 150/150mV, in band 75/75mV, high-frequency 150/150mV; the default peak value is 65535mV, which is equivalent to disabling to avoid false alarms in the factory state. The typical average noise level on site is below 20mV, with peak values typically below 50 to 60mV. Peaks resembling "spikes" may be caused by lightning strikes, equipment start stop, welding, or temporary short circuits, and short-term disturbances may not necessarily affect the bus; If the average noise continues to rise, it indicates the presence of permanent noise sources such as frequency converters, poor shielding, or parallel AC cables. Therefore, the average noise limit should be stricter than the peak limit.

The troubleshooting sequence for noise alarms is very fixed: check whether the shielding layer of each on-site device is cut short and wrapped properly, and do not have multiple grounding points; Check the shielding connections and grounding inside the on-site junction box, intermediate junction box, and marshalling cabinet; Confirm that the AC power cable is not close to the Fieldbus cable; Confirm terminal fastening; High frequency noise also needs to be checked for welding operations, frequency converter grounding, and nearby high-power radio stations. Attention should also be paid to the grounding of the 5W ERP radio, welding, and frequency converter within a range of 1.5m for in band noise. The short to shield alarm "Short to shield+/- ve" may be caused by the addition of a handheld communicator. If Emerson 475 is used on site, the maximum number of devices should be increased by 1 to avoid false alarms; Otherwise, check for shielding cutting, grounding, floating power supply, and water ingress in cables/junction boxes/equipment.

The default low limit of the device signal amplitude is 150mV, the high limit is 1200mV, the alarm delay is 10mV, and the high limit is at least 20mV higher than the low limit. IEC 61158-2 specifies a range of 750 to 1000mV under testing conditions, but the actual range on site can be from 550 to 1200mV. After debugging, it is recommended to set the low limit of the device to 75% of the current value and the high limit to 125% to make the alarm more realistic while retaining margin. If only one device has a low signal, check the branch cable, branch connector, water inlet, and the device itself; If multiple or all devices are low, check if there are more than two terminals, water ingress, or mainline issues on the segment.

The default low limit for the live list of devices is 0, and the high limit is 32, which is equivalent to no alarm. Connecting a handheld communicator will increase the number of devices. If you do not want to alarm, you can increase the high limit by 1. When DCS itself can detect equipment loss, F809F may repeatedly report a low number of devices, and the default limit value can be retained. The segment retransmission rate is equal to the number of retransmissions divided by the total number of Pass Token requests in LAS, calculated based on the past calendar month; The segment retransmission count can be reset separately, but it will not reset the device retransmission. Resetting the segment count does not affect the retransmission rate, as the retransmission rate is calculated based on the total number of device retransmissions, making it easier to observe newly occurring retransmissions.

The segment diagnosis also provides a "Graph Overview" radar chart, with green areas indicating safe zones and black lines indicating measured values. The black line entering the outer yellow area indicates exceeding the high limit, the outer blue area indicates exceeding the high limit, the inner blue area indicates below the low limit, and the inner yellow area indicates below the low limit. This chart is suitable for quickly determining whether a certain segment is voltage, noise, signal amplitude, or retransmission rate deviation, but it cannot replace checking each parameter item by item.

Device TB: Address LAS、 Signal and retransmission

The device node displays the device address, device tag, signal level, number of retransmissions, and retransmission rate. Addresses 16 to 247 are permanent addresses, 248 to 251 are temporary addresses, and 252 to 255 are used for temporary devices or handheld devices. The devices currently serving as LAS will be labeled with [LAS] after their names, and the backup Link Master cannot be identified solely through bus observation, so the navigation tree will not be marked separately. The typical signal level of the device is between 550 and 1200mV, and retransmission refers to the number of times the device fails to return the Pass Token in a timely manner after LAS sends it and tries again; The retransmission rate is the number of retransmissions divided by the total number of PT requests in LAS.

The default high pre alarm limit for device retransmission rate is about 0.1%, which is approximately equal to one retransmission per hour. The calculation of retransmission rate is divided into three stages: from 1 to 5000 PTs, the displayed value approaches the actual value from low to avoid initial false alarms; The accuracy gradually improves with 5000 to 100000 PT; After exceeding 100000 PTs, use moving average to suppress occasional events and respond to changes in communication performance. If a single device retransmits high on site, check the branch lines, connectors, water inlet, and the device itself; If multiple or all devices retransmit high, check if there is only one terminal on the segment or if the terminal has failed, and check the connection between the trunk cable, host, and trunk junction box.

In equipment alarms, if the signal low/low warning only affects one device, focus on checking branch lines and water damage; If multiple devices are affected, check the number of terminals and the segment for water ingress. If there is only one high pre alarm/alarm for retransmission, check the device communication; If there are multiple units, check the terminal and trunk lines. The retransmission rate alarm is a key indicator of the health of device communication, and should be compared with historical values during operation, not just absolute values. The device node can reset the retransmission and retransmission rate of the device using "Reset Retransmissions Count"; If the alarm has been locked and caused by retransmission, the alarm can be confirmed after reset. If there are no other alarms on the segment, it will be cleared.

Alarm limit optimization and maintenance strategy

The "Alarm Limits Optimization" wizard for segment TB can adjust the power low/high limit, noise high limit, device signal amplitude low/high limit, and select whether the device increases or decreases to trigger an alarm. After selecting the power supply model, the wizard provides low/high limits according to the model, such as F101 and F801, which are approximately 21.3 to 24.2V, F102, F6xx, F802, 918 * 1, which are approximately 27.7 to 30.2V, and 918 * 2, which are approximately 18.5 to 22.5V. For non list models, select custom and enter according to the data table. The signal amplitude is adjusted by the current value ± percentage. Only when the calculated low limit is higher than the current low limit and the high limit is lower than the current high limit, will it be accepted. Otherwise, the old value will be retained. The noise high limit is set according to the actual average value, and remains unchanged if the actual value exceeds the threshold listed in the table. All limits must be kept low ≤ low<high ≤ high high, with high being at least 1V (voltage) or 20mV (signal) higher than low.

Daily maintenance suggestion: After commissioning, manually upload first, then run alarm limit optimization, and finally upload once from the DCS engineering station to avoid template coverage; Use 'Private Print' as the debugging report, grouped by parameters and limits with the NE107 symbol; Compare the current value with the exported XML using 'Compare' to track whether the alarm limit has been changed; The trend function is completed by the FDT framework or asset management system and is not within DTM. For unmanned stations, enable latch alarms and confirm them regularly; For the segment being investigated, only scan that segment temporarily, and restore all active segments after completion to avoid missed monitoring.