Content right column
EP = Extended Precision
When upgraded with the hardware option EP (Extended Precision), the CMC 156 test set becomes an ideal instrument for the testing of energy meters. Due to the extremely high accuracy of the EP option, it is possible to test energy meters of class 0.2S, according to IEC687 (PTB certified), without an additional reference meter.
This extremely high level of accuracy also makes the CMC 156 EP ideal for relay manufacturers in their development or type testing. The main difference from a standard CMC 156 is an additional automatic range switching in the current amplifiers, ensuring an increased accuracy over the entire testing range.