Martin (1992: 525):
Affect has been included to cover what Halliday (1978: 33) refers to as the "degree of emotional charge" in a relationship between participants.
 To be clear, this is not to be confused with the system of the same name in appraisal: attitude (interpersonal semantics).
 More accurately, Halliday (1978: 33) is actually citing Pearce's summary of related schemata:
A number of other, more or less related, schemata have been proposed; see especially Ellis 1965, 1966; Gregory 1967. John Pearce summarises these as follows (Doughty et al. 1972, 186-6):
…Tenor…refers to the relationship between participants…not merely variation in formality…but…such questions as the permanence or otherwise of the relationship and the degree of emotional charge in it.
 This has become the system of sociometric rôle in Halliday & Matthiessen (2014: 33):
tenor – who is taking part in the situation: (i) the rôles played by those taking part in the socio-semiotic activity – (1) institutional rôles, (2) status rôles (power, either equal or unequal), (3) contact rôles (familiarity, ranging from strangers to intimates) and (4) sociometric rôles (affect, either neutral or charged, positively or negatively); and (ii) the values that the interactants imbue the domain with (either neutral or loaded, positively or negatively).