The meaning of the red indicator indicates "alarm" condition in both IEC 73 and EN 60204-1.
The instruments that we manufacturer include relays that are tripped at some user defined level. The visual indication of a energized relay is a red LED. The meaning of this relay is determined by the customer during the installation. It may be used to indicated an "alarm" condition, a "go-ahead" condition. or it may not mean either one of these conditions. Unfortunately ,red and green pretty much cover the visible(at least reasonably visible) types of LEDS available. Our instrument is covered under EN61010-1 which I have not reviewed yet on this issue. However, I am assuming (at this moment anyway) that if the LEDs are labled to indicate they are "relay status" indicators, then the red color would be okay. RED is the preferable choice due to its better visibility and lower power requirements. I believe that the intend of the standards is to provide interpretation of an indicator in the absensce of a description of the indicator and that any color is acceptible for an indicator as long as its purpose is clearly displayed. Would the label have to be in country specific language or would a country specific description in the manual be adequate even necessary? Jim Stafford Product Eng HPS
