Command set has changed

This article is for a Legato pump that works properly, but has stopped responding to pump chain commands from a PC.

To resolve the issue:

From Pump Terminal, try sending the command:

Cmd ultra

And see if that fixes the issue.

What has happened is that the pump has switched to a different command set – these  pumps support several command sets, so that they can work with legacy PC programs that were written for older pumps. The first thing the pump does when it receives a command from the PC is to check what command set it is working in. If a second command arrives while the pump Is still checking the command set, it can get overwritten.

The way to solve this is to issue the ‘nvram off’ command before anything else each time the pump is turned on. This will prevent the pump from writing the flow rate to the NVRAM (and potentially overwriting the command set setting by accident). Since that information can be set in Labview, there is no benefit to storing it on the pump. Additionally, PC software can sometimes send the commands over at too high a frequency, damaging the NVRAM. The ‘nvram off’ is not saved, so it needs to be issued each time the pump is turned on for use with Labview or any other automation software.

If your pump is running firmware 3.0.6 or newer, you can alternately use the command:

nvram none

This command IS saved, so you only need to issue it once. It also does a better job of protecting the nvram from unexpected write commands.

Special Notes:

You will need to have Pump Terminal installed.