Meter made by Siemens went round (6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

Meter made by Siemens went round S (=Siemens, i.e. SI unit) + PEED (=went, weed) + O (=round, i.e. pictorially); colloquially, the speedo is the speedometer of a car