Minor change.
digraph slaveconf {
size="7,9"
center=1
ratio=fill
enter_mbox_sync [shape=point,label=""]
enter_fmmu [shape=point,label=""]
enter_sdo_conf [shape=point,label=""]
enter_mapping [shape=point,label=""]
enter_pdo_sync [shape=point,label=""]
enter_saveop [shape=point,label=""]
start -> init [weight=10]
init -> init
init -> error
init -> enter_mbox_sync
init -> clear_fmmus [label="Has FMMUs", weight=10]
clear_fmmus -> clear_fmmus
clear_fmmus -> error
clear_fmmus -> enter_mbox_sync [weight=10]
enter_mbox_sync -> end [label="INIT req."]
enter_mbox_sync -> preop [label="No mailboxes"]
enter_mbox_sync -> mbox_sync [label="Has mailboxes", weight=10]
mbox_sync -> mbox_sync
mbox_sync -> error
mbox_sync -> preop [weight=10]
preop -> preop
preop -> error
preop -> end [label="PREOP req."]
preop -> enter_sdo_conf [weight=10]
enter_sdo_conf -> enter_saveop [label="No configuration"]
enter_sdo_conf -> enter_mapping [label="No SDO configs"]
enter_sdo_conf -> sdo_conf [label="SDO configs", weight=10]
sdo_conf -> sdo_conf
sdo_conf -> error
sdo_conf -> enter_mapping [weight=10]
enter_mapping -> mapping [label="CoE supported", weight=10]
enter_mapping -> enter_pdo_sync
mapping -> mapping
mapping -> error
mapping -> enter_pdo_sync [weight=10]
enter_pdo_sync -> pdo_sync [label="PDO SMs", weight=10]
enter_pdo_sync -> enter_fmmu
pdo_sync -> pdo_sync
pdo_sync -> error
pdo_sync -> enter_fmmu [weight=10]
enter_fmmu -> enter_saveop
enter_fmmu -> fmmu [label="FMMUs to configure", weight=10]
fmmu -> fmmu
fmmu -> error
fmmu -> enter_saveop [weight=10]
enter_saveop -> saveop
saveop -> saveop
saveop -> error
saveop -> end [label="SAVEOP req."]
saveop -> op [weight=10]
op -> op
op -> error
op -> end [weight=10]
}