MP3300iec

One common cause of the CPU load being higher than expected is caused by using a custom Function Block that uses a large structure connected as a VAR_INPUT instead of a VAR_IN_OUT.

When a variable is declared as a VAR_INPUT, the MPiec Controller copies the entire contents of the structure into the Function Block every scan. Other programming languages refer to this technique as “Passing by Value.”  In this situation, the Function Block does not have the ability to alter the contents of the original data. When declaring a variable as VAR_IN_OUT, the MPiec Controller passes a pointer to the original location of the variable rather than a copy of the data. Other programming languages refer to this technique as “Passing by Reference.” The pointer is an internal 32 bit value, which is significantly more efficient than copying the entire contents every scan. This method also gives the Function Block the ability to alter the contents of the structure variable.

To show this example in practice, the attached document shows two scenarios. The first scenario scans a Function Block with a large structure as a VAR_INPUT and results in a high CPU load. The other scenario shows the same structure as a VAR_IN_OUT and has no impact on the CPU load.

The large structure is an array of an array creating 500,000 LREAL’s. There is nothing else in the program, the custom Function Blocks have no code.

Yaskawa motion systems use lithium batteries for mainly two different functions: maintaining Absolute encoder data and preserving CPU non-volatile memory.

The encoder battery used with the ServoPacks (JZSP-BA01) is required if a multi-turn absolute encoder is needed because it holds the multi-turn encoder data when the drive power is down. Therefore, when setting the drive to use the absolute encoder as an incremental encoder or a single-turn absolute encoder, the encoder battery is not needed.  The encoder battery power can be applied via the battery case on the ABS encoder cable (CN2), or through the I/O connector (CN1, for example Sigma7 ML-III ServoPack, pins 14[+] & 15[-]).

Figure1

When using an absolute encoder without the encoder battery case, the battery can be connected to through CN1 connector on the ServoPack:

Figure2

Figure3

The Absolute Encoder Current Draw specification is:

• 20 μA when ServoPack is powered off
• 3 μA when ServoPack is powered on (w/o diode in place)

To determine the worst case battery life, divide the A-hour rating of the battery by the Sum of the current of all encoders when powered off.

For example, assume 16.5 A-hr battery and 16 Encoders are connected: 16.5 A-hr / (.000020 A * 16) = 51500 hours or 5.8 years

For installing and replacing the battery in the ServoPack, refer to:

• YASKAWA SIGMA-7 AC Servo Drives and Motors Technical Supplement (YAI-KAEPS80000123F)
• YASKAWA AC Servo Drives Sigma-V Series Product Catalog (YEA-KAEPS80000042)

The other type of batteries is used for the MP controllers. These batteries (JZSP-BA01) provide a backup power for the CPU non-volatile memory, preserving the SRAM data when CPU power is down. This data includes the retained variables, the alarm history, the absolute encoder offset and the real-time clock data. The SRAM can last for one hour without the battery connected. This battery must be replaced while power is supplied, within 2 weeks of when the BAT indicator first lights. For the MP2600, the SRAM battery power can be applied through the battery connector (CN14), or through the I/O connector (CN13 pins 7[+] & 32[-]).

Figure4 

For installing and replacing the battery in the CPU, refer to:

• YASKAWA MP3200iec Machine Controller Hardware Manual (YAI-SIA-IEC-5)
• YASKAWA MP2600iec Hardware Manual (YEA-SIA-IEC-6)

More references on the encoder usage in Yaskawa motion systems:

• The absolute encoder battery back-up techniques
• Material Safety Data Sheet (MSDS) for Toshiba ER3V and ER6V batteries
• A.810 Absolute Encoder Battery Life and Replacement
• MP940 Dip switch settings, battery and PC cable

If the Vipa Ethernet coupler was previously configured and then modules are added or changed, you must perform an online save through its web page before they will function correctly.  If the new configuration is not saved, the Vipa Ethernet coupler will flash the SF and MS red LED’s when the controller connects.  The I/O status variable in the MotionWorks IEC project will show a status of 0x1000 (connected) or 0x320 (deleted configuration) but the I/O will not update.

To save the configuration on the Vipa Ethernet coupler:

Open the Vipa web page by typing the IP address into the browser’s address bar.

Note:  Disconnect or stop any MPiec controller Ethernet connection to the Vipa bus coupler.

Navigate to the Configuration tab and press the Save button.

After saving the configuration, the Vipa Ethernet coupler must be powered down for at least 20 seconds, and then powered back up.  If the power is short cycled, the Vipa Ethernet coupler will not power up.

See attached document for a screen shot of the web page’s Configuration tab

The controller counts all configured axes and any axes it discovers when the CNFG switch is on. To avoid adding discovered axes to this count, set the CNFG switch to off before the controller is powered on, or disconnect the additional axes.

There is an error in older firmware versions that cause analog output channels with a negative offset to only output the maximum voltage. Use firmware version 3.1.1.1 for all MP2300 type controllers and firmware version 3.5.0 and higher for all other controllers to correct the issue. The 3.5.0 release will be available in April 2018.  Please contact customer support with help in resolving this issue before then.