Annex 7 – Appendix 1 55 no greater than 1 percent of full scale. This is to be carried out for each analyser range calibrated. This table shall also contain other relevant data such as a) Date of calibration b) Span and zero potentiometer readings (where applicable c) Nominal scaled) Reference data of each calibration gas used e) Real and indicated value of each calibration gas used together with the percentage differences f) Calibration pressure of analyser. 3.5. Alternative methods (e.g. computer, electronically controlled range switch) can be used if it is proven to the test agency that these methods give equivalent accuracy.