20-COMM-D Explicit MSG Write

[gmferg 1]

I have been using explicit MSGs to write parameters to PFlex Drive and 20-COMM-D to setup comms for DNet. These will setup Speed Ref, datalinks, etc. This saves a lot of time when commisioning hundreds of drives for a project. Part of this setup requires that I write to params 13, 25, and 26 of the 20-COMM-D to enable datalinks. Since PFlex 70/700 drives have varying numbers of total params and the 20-COMM-D params appear after the drive params, I need to know how many total params the drive has. I can then add 13, 25, and 26 to this total param count to hit the correct 20-COMM-D params. The following MSG setup is supposed to return the total number of drive parameters only. This works about 80% of the time. The other times, the MSG will either error out or return a number representing total number of drive params + 20-COMM-D params. Is there a more reliable method for retrieving the total param count? Is there a better method for writing directly to 20-COMM-D params?

[Ken Roach 194]

You're on the right track using the DPI Parameter Object (Class 0x93). To allow consistent numbering of the 20-COMM-D Adapter's parameters, they begin at Instance 0x4001 (decimal 16385) for the 20-COMM-D Parameter 1 (DPI Port Number). I haven't done as much experimentation with this as you have, so I am surprised that a read of 0x93/0/0 ever gives anything but the number of Drive Parameters. I wonder if this is associated with a particular state of the adapter. You ought to be able to construct and send a Service 0x4C (Set Parameters Scattered) to put a value into Adapter parameters 13, 25, and 26 (0x400D, 0x4019, and 0x401A). Next you'll send a Set Attribute Single to 0x93 / 0x4000 / 0x02 = 1 to load the Adapter Parameters in RAM into NVRAM, followed by a reset service or just a power cycle of the drive. You are on the right track; I wish I had an MCC full of drives to experiment with.

[gmferg 1]

Thank you for the response. I will do some playing when I'm at the customer's site again. I too wish I had a rack of drives to experiment with.

[gmferg 1]

I logged in to a customer's site with VPN access and did some testing. The following MSG setup is what I finally got to work: As a test, I simply changed the Instance number to match each of the three parameters and initiated the MSG each time. Then I entered the parameter for restart and sent a value of 1. After restart, the new settings were active. Now, I will utilize this on my next large DNet project and abandon the total number of parameters method. Thanks for the help Ken.